Wednesday, April 29, 2009

WHO raises alert level to Phase 5 - there will be a pandemic.

WHO link to Video of press conference

Press conference video file for direct downloading

There will be a pandemic -- the question is

how severe?  Dr. Chan says WHO is now

mobilizing every resource - financial

resources from donor countries and the World

Bank, vaccine and drug manufacturers,

governments - in order to ramp up

preparedness and response.  The time to act

is now.

The WHO Statement:


Statement by WHO Director-General, Dr Margaret Chan
29 April 2009

Swine influenza


Ladies and gentlemen,

Based on assessment of all available information, and following several expert consultations, I have decided to raise the current level of influenza pandemic alert from phase 4 to phase 5.

Influenza pandemics must be taken seriously precisely because of their capacity to spread rapidly to every country in the world.

On the positive side, the world is better prepared for an influenza pandemic than at any time in history.

Preparedness measures undertaken because of the threat from H5N1 avian influenza were an investment, and we are now benefitting from this investment.

For the first time in history, we can track the evolution of a pandemic in real-time.

I thank countries who are making the results of their investigations publicly available. This helps us understand the disease.

I am impressed by the work being done by affected countries as they deal with the current outbreaks.

I also want to thank the governments of the USA and Canada for their support to WHO, and to Mexico.

Let me remind you. New diseases are, by definition, poorly understood. Influenza viruses are notorious for their rapid mutation and unpredictable behaviour.

WHO and health authorities in affected countries will not have all the answers immediately, but we will get them.

WHO will be tracking the pandemic at the epidemiological, clinical, and virological levels.

The results of these ongoing assessments will be issued as public health advice, and made publicly available.

All countries should immediately activate their pandemic preparedness plans. Countries should remain on high alert for unusual outbreaks of influenza-like illness and severe pneumonia.

At this stage, effective and essential measures include heightened surveillance, early detection and treatment of cases, and infection control in all health facilities.

This change to a higher phase of alert is a signal to governments, to ministries of health and other ministries, to the pharmaceutical industry and the business community that certain actions should now be undertaken with increased urgency, and at an accelerated pace.

I have reached out to donor countries, to UNITAID, to the GAVI Alliance, the World Bank and others to mobilize resources.

I have reached out to companies manufacturing antiviral drugs to assess capacity and all options for ramping up production.

I have also reached out to influenza vaccine manufacturers that can contribute to the production of a pandemic vaccine.

The biggest question, right now, is this: how severe will the pandemic be, especially now at the start?

It is possible that the full clinical spectrum of this disease goes from mild illness to severe disease. We need to continue to monitor the evolution of the situation to get the specific information and data we need to answer this question.

From past experience, we also know that influenza may cause mild disease in affluent countries, but more severe disease, with higher mortality, in developing countries.

No matter what the situation is, the international community should treat this as a window of opportunity to ramp up preparedness and response.

Above all, this is an opportunity for global solidarity as we look for responses and solutions that benefit all countries, all of humanity. After all, it really is all of humanity that is under threat during a pandemic.

As I have said, we do not have all the answers right now, but we will get them.

Thank you.



April 29, 2009 in Governance/Management | Permalink | Comments (0) | TrackBack (0)

AAAS Policy Alert

For those of you who try to stay current on science policy, I am a member of AAAS and receive its policy alerts. I encourage all of you to join and subscribe to Science.  Here is today's policy alert:

AAAS Policy Alert -- April 29, 2009 


President Addresses National Academies

President Obama addressed the Annual Meeting of the National Academy of Sciences on April 27 and called for a renewed commitment to basic scientific research and education. During his speech he stated that his goal would be to increase our nation's share of federal investment in research and development (R&D) to 3 percent of gross domestic product (GDP). In recent years, the share has hovered around 2.6 percent of GDP. Furthermore, Obama announced the membership of the President's Council of Advisors for Science and Technology (PCAST). Members include past AAAS President Shirley Ann Jackson of RPI, as well as former Board member Rosina Bierbaum and current AAAS Treasurer David Shaw. They join former AAAS President John Holdren who is both the U.S. President's science advisor and co-chair of PCAST.

Budget News

The House and Senate have nominated the conferees to resolve the differences between their respective versions of the FY 2010 budget resolution. House members include: Budget Committee Chairman John Spratt (D-SC), Ranking Member Paul Ryan (R-WI), and Reps. Allen Boyd (D-FL), Rosa DeLauro (D-CT) and Jeb Hensarling (R-TX). Senate members include Budget Committee Chair Kent Conrad (D-ND), Ranking Member Judd Gregg (R-NH) and Sen. Patty Murray (D-WA). The conferees met today (April 27) to begin deliberating over a consensus document.

Other Congressional News

Congressional Climate Change Update. The House Energy and Commerce Committee held four days of hearings on the American Clean Energy and Security Act, with much debate on the merits of moving ahead on the climate and energy package. Subcommittee markup of the bill has been pushed back to next week, with details such as how to allocate permits to emit greenhouse gases and how the revenues will be used yet to be determined. Meanwhile Senate Environment and Public Works Chairwoman Barbara Boxer (D-CA) announced the formation of five working groups to find compromises in several areas of concern: regional issues, cost containment, targets and timetables, market oversight and coal research and technology. The Senate Foreign Relations Committee heard from Todd Stern, special envoy for climate change at the State Department, who testified on the diplomatic cost of inaction on climate change and emphasized the need for all countries - developed and developing - to engage in negotiations with "common but differentiated responsibilities." Stern is leading the first session of the Major Economies Forum on Energy and Climate on April 27-28, a White House initiative to develop a dialogue among major developed and developing economies on climate change.

New Bill Promotes Science Envoys. Last week, Senator Richard Lugar (R-IN) introduced legislation (S. 838) that recognizes the importance of international scientific cooperation and the work of organizations such as AAAS and the National Academies in this area. The legislation tasks the State Department to appoint Science Envoys to represent our nation and promote international collaboration.

Executive Branch

Presidential Memo on Scientific Integrity. OSTP issued a Presidential Memo on scientific integrity in the April 23 Federal Register and requests public comments on six principles for maintaining and protecting the responsible use of science in decision-making. The memo builds upon a March 9, 2009 memorandum from the President that called on OSTP to issue a set of recommendations within 120 days. OSTP has launched a blog on the subject and is seeking comments on the selection of scientists to serve in the executive branch, peer-review of science used in policy-making, access to scientific data used in policy-making, and whistleblower protection. Comments are due May 13, 2009.

NIH Stem Cell Guidelines Now Open for Comment. The NIH Guidelines for Human Stem Cell Research are now open for public comment until May 26.

NCI Director Speaks on Cancer Plan. National Cancer Institute Director John Niederhuber recently spoke of his institute's plans in the wake of President Obama's cited goal of doubling funds for cancer research. Included would be a boost in the NCI payline to fund more meritorious research grants, as well as more grants to first-time investigators and new faculty researchers. There will also be a focus on personalized cancer care.

EPA Examines Ocean Acidification. On April 14, EPA issued a Federal Register notice requesting information on ocean acidification, the changing of ocean chemistry from increases in carbon dioxide that affects coral reefs and other marine organisms. In response to a lawsuit by the Center for Biological Diversity, EPA is trying to determine whether changes are needed to the water quality criteria under the Clean Water Act. Comments are due June 15, 2009.

Toxics Reporting Tightened. As mandated in the 2009 omnibus appropriations bill, EPA finalized changes to reporting requirements under the Toxics Release Inventory that will take effect July 1. The final rules restore more stringent reporting requirements than those from a Bush-era rule that raised the pollution threshold for reporting. In 2006, AAAS submitted comments stating that the increased threshold would "threaten the ability of researchers to identify and understand potential threats to the environment and public health in a scientifically rigorous manner."

FDA Widens Access to "Morning-After" Pill. The Food and Drug Administration will now allow 17-year-olds to purchase the Plan B "morning-after" pill without a prescription, following a recent federal court order that it do so. The decision has been labeled a "triumph of science over politics" because of widespread concern that the previous administration overruled scientific advice on making the pill available over the counter, leading the FDA's top women's health official, Susan Wood, to resign in protest in 2005.

Nation's First CTO: Clarification. Last week's Policy Alert reported on the President's selection of Aneesh Chopra to be the nation's first chief technology officer. It has since been reported that the CTO will also be one of the associate directors of the Office of Science and Technology Policy (OSTP) concerned with overall technology policy and innovation strategies across federal departments. Chopra's position (which is subject to Senate confirmation) should not be confused with that of Vivek Kundra, recently named Chief Information Officer, who is located in the Office of Management and Budget (OMB), overseeing day-to-day information technology spending and interagency operations.

Elsewhere

Climate Risk Report Released. Led by the Heinz Center and CERES, a coalition of insurance, government, environmental, and investment organizations released a report, Resilient Coasts: A Blueprint for Action that listed steps the nation can take to drastically reduce rising coastal hazard risks and their associated economic impacts.

Texas School Board Chairman Up for Confirmation. Texas State Board of Education Chairman Don McLeroy, a vocal opponent of teaching evolution, is up for Senate confirmation by the state Senate, and during a recent hearing some members of the Senate Nominations Committee expressed dissatisfaction with McLeroy's performance. One state senator said McLeroy has "created a hornet's nest" and noted that 15 bills filed during this legislative session would strip powers from the state school board. Even if McLeroy is not confirmed as chairman, he will still remain a member of the board. In other news, the Institute for Creation Research is now suing in U.S. District Court over the Texas Higher Education Coordinating Board's decision to deny its request to offer a master's degree in science education.

Animal Rights Activists Charged. Two animal rights activists have been arraigned on charges of conspiracy, stalking and other crimes, including attempted fire-bombing, against UCLA scientists engaged in animal research.



Publisher: Alan I. Leshner
Editor: Joanne Carney
Contributors: Erin Heath, Earl Lane, Steve Nelson, Al Teich, Kasey White

NOTE: The AAAS Policy Alert is a newsletter provided to AAAS Members to inform them of developments in science and technology policy that may be of interest.  Information in the Policy Alert is gathered from published news reports, unpublished documents, and personal communications.  Although the information contained in this newsletter is regarded as reliable, it is provided only for the convenience and  private use of our members.  Comments and suggestions regarding the Policy Alert are welcome.  Please write to alert@aaas.org.



April 29, 2009 in Climate Change, Energy, Governance/Management, Legislation, Physical Science, Science, Social Science, Sustainability, Toxic and Hazardous Substances, US, Water Resources | Permalink | TrackBack (0)

How this virus developed and why it may be a killer

The Mexican swine flu virus is a swine influenza A/H1N1 virus hybridized (mixed) with human and bird viruses.  We have some immunity to human flu and to some strains of swine influenza A/H1N1;  We don't have immunity to bird flu, which is why that virus is so virulent - with a kill ratio of almost 50% -- and why so much pandemic planning and preparedness focused on bird flu.

New Scientist reports:

This type of virus emerged in the US in 1998 and has since become endemic on hog farms across North America. Equipped with a suite of pig, bird and human genes, it was also evolving rapidly.  Flu infects many animals, including waterfowl, pigs and humans. Birds and people rarely catch flu viruses adapted to another host, but they can pass flu to pigs, which also have their own strains.If a pig catches two kinds of flu at once it can act as a mixing vessel, and hybrids can emerge with genes from both viruses. This is what happened in the US in 1998. Until then, American pigs had regular winter flu, much like people, caused by a mutated virus from the great human pandemic of 1918, which killed pigs as well as at least 50 million people worldwide. This virus was a member of the H1N1 family - with H and N being the virus's surface proteins haemagglutinin and neuraminidase.  Over decades, H1N1 evolved in pigs into a mild, purely swine flu, and became genetically fairly stable. In 1976, there was an outbreak of swine H1N1 in people at a military camp [Fort Dix] in New Jersey, with one death. The virus did not spread efficiently, though, and soon fizzled out.

But in 1998, says Richard Webby of St Jude's Children's Research Hospital in Memphis, Tennessee, swine H1N1 hybridised with human and bird viruses, resulting in "triple reassortants" that surfaced in Minnesota, Iowa and Texas. The viruses initially had human surface proteins and swine internal proteins, with the exception of three genes that make RNA polymerase, the crucial enzyme the virus uses to replicate in its host. Two were from bird flu and one from human flu. Researchers believe that the bird polymerase allows the virus to replicate faster than those with the human or swine versions, making it more virulent.

By 1999, these viruses comprised the dominant flu strain in North American pigs and, unlike the swine virus they replaced, they were actively evolving. There are many versions with different pig or human surface proteins, including one, like the Mexican flu spreading now, with H1 and N1 from the original swine virus. All these viruses still contained the same "cassette" of internal genes, including the avian and human polymerase genes, reports Amy Vincent of the US Department of Agriculture (USDA) in Ames, Iowa (Advances in Virus Research, vol 72, p 127). "They are why the swine versions of this virus easily outcompete those that don't have them," says Webby.

But the viruses have been actively switching surface proteins to evade the pigs' immunity. There are now so many kinds of pig flu that it is no longer seasonal. One in five US pig producers actually makes their own vaccines, says Vincent, as the vaccine industry cannot keep up with the changes. This rapid evolution posed the "potential for pandemic influenza emergence in North America", Vincent said last year. Webby, too, warned in 2004 that pigs in the US are "an increasingly important reservoir of viruses with human pandemic potential". One in five US pig workers has been found to have antibodies to swine flu, showing they have been infected, but most people have no immunity to these viruses.

The virus's rapid evolution created the potential for a pandemic to emerge in North America.  Our immune response to flu, which makes the difference between mild and potentially lethal disease, is mainly to the H surface protein. The Mexican virus carries the swine version, so the antibodies we carry to human H1N1 viruses will not recognise it. That's why the CDC warned last year that swine H1N1 would "represent a pandemic threat" if it started circulating in humans. The avian polymerase genes are especially worrying, as similar genes are what make H5N1 bird flu lethal in mammals and what made the 1918 human pandemic virus so lethal in people. "We can't yet tell what impact they will have on pathogenicity in humans," says Webby. It appears the threat has now resulted in the Mexican flu. "The triple reassortant in pigs seems to be the precursor," Robert Webster, also at St Jude's, told New Scientist.

While researchers focused on livestock problems could see the threat developing, it is not one that medical researchers focused on human flu viruses seemed to have been aware of. "It was confusing when we looked up the gene sequences in the database," says Wendy Barclay of Imperial College London, who has been studying swine flu from the recent US cases. "The polymerase gene sequences are bird and human, yet they were reported in viruses from pigs."

So where did the Mexican virus originate? The Veratect Corporation based in Kirkland, Washington, monitors world press and government reports to provide early disease warnings for clients, including the CDC. Their first inkling of the disease was a 2 April report of a surge in respiratory disease in a town called La Gloria, east of Mexico City, which resulted in the deaths of three young children. Only on 16 April - after Easter week, when millions of Mexicans travel to visit relatives - reports surfaced elsewhere in the country.

Local reports in La Gloria blamed pig farms in nearby Perote owned by Granjas Carroll, a subsidiary of US hog giant Smithfield Foods. The farms produce nearly a million pigs a year. Smithfield Foods, in a statement, insists there are "no clinical signs or symptoms" of swine flu in its pigs or workers in Mexico. That is unsurprising, as the company says it "routinely administers influenza virus vaccination to swine herds and conducts monthly tests for the presence of swine influenza." The company would not tell New Scientist any more about recent tests. USDA researchers say that while vaccination keeps pigs from getting sick, it does not block infection or shedding of the virus.

All the evidence suggests that swine flu was a disaster waiting to happen. But it got little research attention, perhaps because it caused mild infections in people which didn't spread. Now one swine flu virus has stopped being so well-behaved.

This leads us to the policy question: why should humans keep pigs?  Like other meat, pigs consume an extraordinary amount of resources to provide nutrition.  Maybe the ancient Israelites had an insight that we have lacked -- there may be more wisdom in the Torah and its laws than we knew.  Perhaps it is time, or past time, for our eating habits to evolve lest an even more virulent strain of swine flu develop.  Assuming that this pandemic passes without too many deaths, we may need to rethink whether it is good to keep large quantities of pigs.  For now, the virulent bird flu does not seem easily communicable.  Let's keep it that way. 

April 29, 2009 in Agriculture, Asia, Australia, Biodiversity, Current Affairs, Economics, EU, Food and Drink, Governance/Management, International, North America, Religion, Sustainability, US | Permalink | TrackBack (0)

WHO Update 5 - April 29th

29 April 2009 -- The situation continues to evolve rapidly. As of 18:00 GMT, 29 April 2009, nine countries have officially reported 148 cases of swine influenza A/H1N1 infection. The United States Government has reported 91 laboratory confirmed human cases, with one death. Mexico has reported 26 confirmed human cases of infection including seven deaths.

The following countries have reported laboratory confirmed cases with no deaths - Austria (1), Canada (13), Germany (3), Israel (2), New Zealand (3), Spain (4) and the United Kingdom (5).

April 29, 2009 in Governance/Management | Permalink | TrackBack (0)

Its time to undertake all of the community mitigation efforts: we have a PSI category 4 pandemic at least and WHO is set to declare the pandemic to be stage 5

Even a day makes a difference!  WHO is now considering increasing its phase to Phase 5.  The US now has a death rate that exceeds 1%, so the Pandemic Severity Index in the US is a Category 4 severity, especially given the death rate in Mexico which appears to be in excess of 2% and thus a Category 5 severity.  So NOW would be the time to begin all of those community mitigation efforts in every affected state....and at least most of them throughout the US.  For the details about what we should do and why, see this reposting from yesterday.  Secondguessing the CDC  But suffice it to say, we need to isolate the ill, quarentine those in close contact with them at home, close schools and deliver instruction on line, reduce business meetings and encourage telework, cancel large gatherings, and in general promote social distancing.  My guess is that it will take another dozen deaths and the spread to another 15 states before the CDC issues these recommendations.   

April 29, 2009 in Governance/Management | Permalink | Comments (0) | TrackBack (0)

Tuesday, April 28, 2009

Bush Administration Midnight ESA Consultation Rule Revoked

  FWS Press Release:

Salazar and Locke Restore Scientific Consultations under the Endangered
             Species Act to Protect Species and their Habitats

WASHINGTON, D.C. – Secretary of Commerce Gary Locke and Secretary of the Interior Ken Salazar today announced that the two departments are revoking an eleventh-hour Bush administration rule that undermined Endangered Species Act (ESA) protections. Their decision requires federal agencies to once again consult with federal wildlife experts at the U.S. Fish and Wildlife Service and the National Oceanic and Atmospheric Administration – the two agencies that administer the ESA – before taking any action that
may affect threatened or endangered species.

“By rolling back this 11th hour regulation, we are ensuring that threatened and endangered species continue to receive the full protection of the law,” Salazar said. “Because science must serve as the foundation for decisions we make, federal agencies proposing to take actions that might affect threatened and endangered species will once again have to consult with biologists at the two departments.”

“For decades, the Endangered Species Act has protected threatened species and their habitats,” said Commerce Secretary Gary Locke. “Our decision affirms the Administration’s commitment to using sound science to promote conservation and protect the environment.”

April 28, 2009 in Biodiversity, Governance/Management, Physical Science, US | Permalink | Comments (0) | TrackBack (0)

Findlaw environmental case summaries March 2009

Table of Contents - March 16-29th

ENVIRONMENTAL LAW CASES

• Trout Unlimited v. Lohn
• Natural Resources Def. Coun. v. EPA

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U.S. 9th Circuit Court of Appeals, March 16, 2009
Trout Unlimited v. Lohn, No. 07-35623
In a challenge to a National Marine Fisheries Service (NMFS) regulation distinguishing between natural and hatchery-spawned salmon and steelhead when determining the level of protection each species should receive under the Endangered Species Act, the majority of District Court's rulings are affirmed where NMFS decisions were not arbitrary, but reversed where summary judgment to Plaintiff was erroneous. Read more...

U.S. D.C. Circuit Court of Appeals, March 20, 2009
Natural Resources Def. Coun. v. EPA, No. 07-1151
Petitioner's petition for review of EPA air quality regulations is denied, where: 1) Petitioner failed to object to the EPA's definition of "natural event" during the rulemaking process; and 2) the preamble to the regulations was not a final agency action, and thus was not reviewable under the Clean Air Act. Read more...

Table of Contents - March 9 - 15th

ENVIRONMENTAL LAW CASES

• Am. Bird Conservancy v. Kempthorne
• Dallas v. Hall
• Hempstead County Hunting Club v. Southwestern Electric Power
• Washington v. Chu
• Delaware Dept. of Natural Res. & Envt'l. Ctrl. v. FERC
• Eastern Niagara Pub. Pwr. Alliance & Pub. Pwr. Coal. v. FERC
• State of California v. Allstate Ins. Co.
• People v. Tri-Union Seafoods, LLC

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U.S. 3rd Circuit Court of Appeals, March 11, 2009
Am. Bird Conservancy v. Kempthorne, No. 07-4609
In an action involving environmental rulemaking, dismissal of plaintiff's complaint for lack of subject matter jurisdiction is affirmed where the challenge to the denial by the Fish and Wildlife Service to undertake an emergency rulemaking listing the red knot species of bird endangered, is rendered moot by the publication of the warranted but precluded by higher priority listing in the periodic Candidate Notice of Review. Read more...

U.S. 5th Circuit Court of Appeals, March 12, 2009
Dallas v. Hall, No. 08-10890
In an action by a city against the Fish & Wildlife Service based on the agency's establishment of a conservation easement on the city's land, summary judgment for Defendant is affirmed, where the FWS considered a reasonable range of alternatives before creating the easement, and was not required to consider the impact on a potential water source. Read more...

U.S. 8th Circuit Court of Appeals, March 12, 2009
Hempstead County Hunting Club v. Southwestern Electric Power , No. 08-2613
In an environmental action, appeal of a denial of a preliminary injunction to halt preconstruction activities for defendant's failure to obtain the permit required by the Clean Air Act is dismissed as moot where defendant has since received the Clean Air Act permit and lawfully begun construction at the site. Read more...

U.S. 9th Circuit Court of Appeals, March 10, 2009
Washington v. Chu, No. 06-35227
In an action by the state of Washington against the Department of Energy for violation of hazardous waste management regulations, summary judgment for Plaintiff is affirmed, where the Washington Hazardous Waste Management Act plainly exempts designated nuclear waste from the storage and land-disposal prohibitions "with respect to WIPP" only. Read more...

U.S. D.C. Circuit Court of Appeals, March 13, 2009
Delaware Dept. of Natural Res. & Envt'l. Ctrl. v. FERC, No. 07-1007
Petitioner state agency's petition for review of FERC's approval of an application to operate a natural gas site is dismissed, where Petitioner lacked standing to challenge the order because it was expressly conditioned on Petitioner's approval. Read more...

U.S. D.C. Circuit Court of Appeals, March 13, 2009
Eastern Niagara Pub. Pwr. Alliance & Pub. Pwr. Coal. v. FERC, No. 07-1472
Petitioner's petition for review of the Federal Energy Regulatory Commission's (FERC) approval of a state agency's license to operate a power project is denied, where FERC's decision to issue the license was reasonable and reasonably explained. Read more...

Supreme Court of California, March 09, 2009
State of California v. Allstate Ins. Co. , No. S149988
In an action arising from efforts to obtain insurance coverage for property damage liability imposed in a federal lawsuit as a result of discharges from a hazardous waste disposal facility, grant of defendant's motion for summary judgment is reversed where: 1) triable issues of fact exist as to whether the 1969 overflow fell within the meaning of the absolute pollution exclusion for watercourses contained in the insurance policy; 2) evidence the State should have known flooding was likely is insufficient to prove as an undisputed fact that the waste discharge in 1978 due to flooding was expected and therefore nonaccidental; and 3) there is a triable issue as to whether the cost of repairing the property damage from the 1969 and 1978 discharges can be quantitatively divided among the various causes of contamination. Read more...

California Appellate Districts, March 11, 2009
People v. Tri-Union Seafoods, LLC, No. A116792
In an action involving food warnings, trial court's ruling for the defendant is affirmed where substantial evidence supports the trial courts finding that methylmercury is naturally occurring in canned tuna and thus defendants and other tuna companies are exempt from the warning requirements of Proposition 65. Read more...

Table of Contents - March 2 - 8th

ENVIRONMENTAL LAW CASES

• Summers v. Earth Island Inst.
• Martex Farms, S.E. v. US EPA
• Izaak Walton League of Am., Inc. v. Kimball
• Latino Issues Forum v. EPA

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U.S. Supreme Court, March 03, 2009

Summers v. Earth Island Inst., No. 07-463
In an action challenging Forest Service regulations exempting certain land management activities from the agency's review process, an injunction against the regulations is reversed where Plaintiffs lacked standing to challenge the regulations absent a live dispute over a concrete application of those regulations. Read more...

U.S. 1st Circuit Court of Appeals, March 05, 2009
Martex Farms, S.E. v. US EPA, No. 08-1311
Final decision and order of the Environmental Appeals Board holding plaintiff liable for violations of the Federal Insecticide, Fungicide, and Rodenticide Act is affirmed where: 1) there is no legal basis for plaintiff's argument that the EPA's enforcement action amounted to selective prosecution; 2) plaintiff's claim that it was deprived of a full and fair opportunity to present its case fails as the denial of its motion to depose four witnesses was justified; and 3) there is no evidence that there is any basis for reversal as to the substantive violations committed by plaintiff. Read more...

U.S. 8th Circuit Court of Appeals, March 06, 2009
Izaak Walton League of Am., Inc. v. Kimball , No. 07-3689
In an action involving the Boundary Waters Canoe Area Wilderness Act, district court's grant of defendant's motion for summary judgment is affirmed where: 1) plaintiff's claims that the Forest Service violated the Act are time barred by the six year statute of limitations in the Act; and 2) there is no appellate jurisdiction over the appeal of the district court's order remanding the matter to the Forest Service to prepare an environmental impact statement assessing the sound impact of the proposed snowmobile trail. Read more...

U.S. 9th Circuit Court of Appeals, March 05, 2009
Latino Issues Forum v. EPA, No. 06-71907
In a petition for review of the EPA's approval of a state air-pollutant reduction program, the petition is denied where the EPA acted lawfully under 42 U.S.C. section 7509(d)(2) by not requiring implementation of "all feasible measures" into the program. Read more...

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April 28, 2009 in Air Quality, Cases, Energy, Environmental Assessment, Forests/Timber, Governance/Management, Land Use, Law, Science, Sustainability, Toxic and Hazardous Substances, US | Permalink | TrackBack (0)

Findlaw environmental case summaries - March 30 - April 3

Table of Contents

ENVIRONMENTAL LAW CASES

• Entergy Corp. v. Riverkeeper, Inc.
• New Jersey Dept. of Envtl. Prot. v. US Nuclear Regulatory Comm'n
• Columbia Venture LLC v. S.C. Wildlife Fed.
• Center for Biological Diversity v. Marina Pt. Dev. Co.

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U.S. Supreme Court, April 01, 2009
Entergy Corp. v. Riverkeeper, Inc., No. 07-588
In a petition for review of EPA national performance standards for cooling water intake structures, the grant of the petition is reversed, where the EPA permissibly relied on cost-benefit analysis in setting the national performance standards and in providing for cost-benefit variances from those standards. Read more...

U.S. 3rd Circuit Court of Appeals, March 31, 2009
New Jersey Dept. of Envtl. Prot. v. US Nuclear Regulatory Comm'n, No. 07-2271
Petition for review of an Nuclear Regulatory Commission decision denying NJ Dept. of Environmental Protection request to intervene in relicensing proceedings for the Oyster Creek Nuclear Generating Station is denied where in reviewing the application to relicense the nuclear power facility, the Commission is not required to make an environmental impact analysis of a hypothetical terrorist attack on the facility as the relicensing of Oyster Creek does not have a reasonably close causal relationship with the environmental effects that would be caused by a terrorist attack. The NRC also already addressed the environmental impact of such an attack in its Generic Environmental Impact Statement and site-specific Supplemental Environmental Impact Statement. Read more...

U.S. 4th Circuit Court of Appeals, April 03, 2009
Columbia Venture LLC v. S.C. Wildlife Fed., No. 05-2398
In a challenge to a FEMA decision regarding certain base flood elevation determinations, the District Court's order vacating those determinations is reversed, where Plaintiffs failed to show that they were prejudiced by FEMA's failure to timely publish notice of the decision in the Federal Register. Read more.

U.S. 9th Circuit Court of Appeals, March 30, 2009
Center for Biological Diversity v. Marina Pt. Dev. Co., No. 06-56193
In an action under the Clean Water Act (CWA) and Endangered Species Act (ESA), judgment for Plaintiffs is reversed, where: 1) Plaintiffs did not give sufficiently specific notice of intent to sue under the CWA; and 2) the ESA action was moot because the species at issue had been delisted during the pendency of the appeal. Award of attorney's fees to Plaintiffs is affirmed, where the mootness of the ESA action did not affect the fee award. Read more...

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April 28, 2009 in Air Quality, Biodiversity, Cases, Governance/Management, Sustainability, US, Water Quality | Permalink | TrackBack (0)

Bending over backwards: Waxman and Markey grant Republicans another day of hearings on climate change bill

Listing the 40 days of hearings that have already been held, Waxman and Market nevertheless agree to hold another day of hearings on May 1, 2009.  The list is a good beginning for a legislative history on the bill. hearings list I I just hope that the quality of witnesses is better than Newt Gingrich saying that he's still not sure that global warming is caused by humans.

April 28, 2009 in Air Quality, Climate Change, Current Affairs, Energy, Governance/Management, Legislation, Sustainability, US | Permalink | Comments (0) | TrackBack (0)

Monday, April 27, 2009

CDC Guidance regarding Swine Flu

US Count at 40 cases in California, Kansas, NYC, Ohio, and Texas as of 11 am PST

Here's the latest from CDC:

Swine Flu website last updated April 27, 2009 1:00 PM ET

U.S. Human Cases of Swine Flu Infection
(As of April 27, 2009 1:00 PM ET)
State # of laboratory
confirmed cases
California 7 cases
Kansas 2 cases
New York City 28 cases
Ohio 1 case
Texas 2 cases
TOTAL COUNT 40 cases
International Human Cases of Swine Flu Infection
See: World Health OrganizationExternal Web Site Policy.

Human cases of swine influenza A (H1N1) virus infection have been identified in the United States. Human cases of swine influenza A (H1N1) virus infection also have been identified internationally. The current U.S. case count is provided below.

An investigation and response effort surrounding the outbreak of swine flu is ongoing.

CDC is working very closely with officials in states where human cases of swine influenza A (H1N1) have been identified, as well as with health officials in Mexico, Canada and the World Health Organization. This includes deploying staff domestically and internationally to provide guidance and technical support.

CDC activated its Emergency Operations Center to coordinate the agency's response to this emerging health threat and yesterday the Secretary of the Department Homeland Security, Janet Napolitano, declared a public health emergency in the United States. This will allow funds to be released to support the public health response. CDC's goals during this public health emergency are to reduce transmission and illness severity, and provide information to assist health care providers, public health officials and the public in addressing the challenges posed by this newly identified influenza virus. To this end, CDC has issued a number of interim guidance documents in the past 24 hours. In addition, CDC's Division of the Strategic National Stockpile (SNS) is releasing one-quarter of its antiviral drugs, personal protective equipment, and respiratory protection devices to help states respond to the outbreak. Laboratory testing has found the swine influenza A (H1N1) virus susceptible to the prescription antiviral drugs oseltamivir and zanamivir. This is a rapidly evolving situation and CDC will provide updated guidance and new information as it becomes available.

April 27, 2009 in Governance/Management | Permalink | Comments (0) | TrackBack (0)

Day late and a dollar short on swine flu response

Reasonably intelligent people could tell on Saturday morning that the appropriate pandemic level was Phase 4 (or even 5), that people should be advised not to travel to Mexico, California, and Texas, and I would argue that travel be stopped.  And I can understand not saying anything until consultation occurred and measures were in place.  But it appears to me that WHO, CDC, and the White House, were a day or two late in treating this situation as a genuine pandemic risk.  I hope that we will not live (or die) to regret that delay.  Obviously, the cat may have already been out of the bag as WHO argues, but I still think that closing borders would have been wise.  Now, today WHO raised the level to phase 4, but says that closing the borders will no longer do any good given the spread to the U.S. and Canada.  Apparently there are other countries reporting influenza like illnesses not yet confirmed as swine flu.  But absent a spread outside North America, I still think that it make sense to close borders, even if only to delay the spread across these large countries.

Here's WHO's statement after the second meeting of the Emergency Committee today:


Statement by WHO Director-General, Dr Margaret Chan
27 April 2009

Swine influenza


The Emergency Committee, established in compliance with the International Health Regulations (2005), held its second meeting on 27 April 2009.

The Committee considered available data on confirmed outbreaks of A/H1N1 swine influenza in the United States of America, Mexico, and Canada. The Committee also considered reports of possible spread to additional countries.

On the advice of the Committee, the WHO Director-General decided on the following.

The Director-General has raised the level of influenza pandemic alert from the current phase 3 to phase 4.

The change to a higher phase of pandemic alert indicates that the likelihood of a pandemic has increased, but not that a pandemic is inevitable.

As further information becomes available, WHO may decide to either revert to phase 3 or raise the level of alert to another phase.

This decision was based primarily on epidemiological data demonstrating human-to-human transmission and the ability of the virus to cause community-level outbreaks.

Given the widespread presence of the virus, the Director-General considered that containment of the outbreak is not feasible. The current focus should be on mitigation measures.

The Director-General recommended not to close borders and not to restrict international travel. It was considered prudent for people who are ill to delay international travel and for people developing symptoms following international travel to seek medical attention.

The Director-General considered that production of seasonal influenza vaccine should continue at this time, subject to re-evaluation as the situation evolves. WHO will facilitate the process needed to develop a vaccine effective against A/H1N1 virus.

The Director-General stressed that all measures should conform with the purpose and scope of the International Health Regulations.

April 27, 2009 in Governance/Management | Permalink | TrackBack (0)

Saturday, April 25, 2009

CDC Health Advisory

This is an official CDC Health Advisory CDC Link Distributed via Health Alert Network April 25, 2009, 3:00 EST (03:00 PM EDT) CDCHAN-000281-2009-04-25-ALT-N Investigation and Interim Recommendations: Swine Influenza (H1N1) CDC, in collaboration with public health officials in California and Texas, is investigating cases of febrile respiratory illness caused by swine influenza (H1N1) viruses. As of 11 AM (EDT) April 25, 2009, 8 laboratory confirmed cases of Swine Influenza infection have been confirmed in the United States. Four cases have been reported in San Diego County, California. Two cases have been reported in Imperial County California. Two cases have been reported in Guadalupe County, Texas. Of the 8 persons with available data, illness onsets occurred March 28-April 14, 2009. Age range was 7-54 y.o. Cases are 63% male. The viruses contain a unique combination of gene segments that have not been reported previously among swine or human influenza viruses in the U.S. or elsewhere. At this time, CDC recommends the use of oseltamivir or zanamivir for the treatment of infection with swine influenza viruses. The H1N1 viruses are resistant to amantadine and rimantadine but not to oseltamivir or zanamivir. It is not anticipated that the seasonal influenza vaccine will provide protection against the swine flu H1N1 viruses. CDC has also been working closely with public health officials in Mexico, Canada and the World Health Organization (WHO). Mexican public health authorities have reported increased levels of respiratory disease, including reports of severe pneumonia cases and deaths, in recent weeks. CDC is assisting public health authorities in Mexico by testing specimens and providing epidemiological support. As of 11:00 AM (EDT) April 25, 2009, 7 specimens from Mexico at CDC have tested positive for the same strain of swine influenza A (H1N1) as identified in U.S. cases. However, no clear data are available to assess the link between the increased disease reports in Mexico and the confirmation of swine influenza in a small number of specimens. WHO is monitoring international cases. Further information on international cases may be found at: http://www.who.int/csr/don/2009_04_24/en/index.html Clinicians should consider swine influenza infection in the differential diagnosis of patients with febrile respiratory illness and who 1) live in San Diego or Imperial counties, California, or Guadalupe County, Texas, or traveled to these counties or 2) who traveled recently to Mexico or were in contact with persons who had febrile respiratory illness and were in one of the three U.S. counties or Mexico during the 7 days preceding their illness onset. Patients who meet these criteria should be tested for influenza, and specimens positive for influenza should be sent to public health laboratories for further characterization. Clinicians who suspect swine influenza virus infections in humans should obtain a nasopharyngeal swab from the patient, place the swab in a viral transport medium, refrigerate the specimen, and then contact their state or local health department to facilitate transport and timely diagnosis at a state public health laboratory. CDC requests that state public health laboratories promptly send all influenza A specimens that cannot be subtyped to the CDC, Influenza Division, Virus Surveillance and Diagnostics Branch Laboratory. Persons with febrile respiratory illness should stay home from work or school to avoid spreading infections (including influenza and other respiratory illnesses) to others in their communities. In addition, frequent hand washing can lessen the spread of respiratory illness. CDC has not recommended that people avoid travel to affected areas at this time. Recommendations found at http://wwwn.cdc.gov/travel/contentSwineFluUS.aspx will help travelers reduce risk of infection and stay healthy. Clinical guidance on laboratory safety, case definitions, infection control and information for the public are available at:http://www.cdc.gov/swineflu/investigation.htm. • Swine Influenza A (H1N1) Virus Biosafety Guidelines for Laboratory Workers: http://www.cdc.gov/swineflu/guidelines_labworkers.htm • Interim Guidance for Infection Control for Care of Patients with Confirmed or Suspected Swine Influenza A (H1N1) Virus Infection in a Healthcare Setting: http://www.cdc.gov/swineflu/guidelines_infection_control.htm • Interim Guidance on Case Definitions for Swine Influenza A (H1N1) Human Case Investigations: http://www.cdc.gov/swineflu/casedef_swineflu.htm Morbidity and Mortality Weekly Reports Dispatch (April 24) provide detailed information about the initial cases at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0424a1.htm For more information about swine flu: http://www.cdc.gov/swineflu
Additional information is also available by calling 1-800-CDC-INFO (1-800-232-4636) ____________________________________________________________________________________ Categories of Health Alert messages: Health Alert conveys the highest level of importance; warrants immediate action or attention. Health Advisory provides important information for a specific incident or situation; may not require immediate action. Health Update provides updated information regarding an incident or situation; unlikely to require immediate action. ##This Message was distributed to State and Local Health Officers, Public Information Officers, Epidemiologists and HAN Coordinators as well as Clinician organizations##

April 25, 2009 in Current Affairs, Governance/Management, International, North America, Physical Science, Sustainability, US | Permalink | Comments (0) | TrackBack (0)

Local flu preparedness planning

As of 4:30 pm PDT, 11 cases of H1N1 swine flu have been confirmed in the US -- now including Kansas.

U.S. Human Cases of Swine Flu Infection
State # of laboratory
confirmed cases
California 7 cases
Texas 2 cases
Kansas 2 cases
TOTAL COUNT 11 cases
International Human Cases of Swine Flu Infection
See: World Health OrganizationExternal Web Site Policy.
As of April 25th, 2009 7:30 p.m. EDT


Oregon Flu Plan 

Marion County Pandemic Flu Resource Page

Marion County Family Preparedness Brochure

April 25, 2009 in Current Affairs, Governance/Management, International, North America, Physical Science, US | Permalink | Comments (0) | TrackBack (0)

Swine Flu with Pandemic Potential Hits US and Mexico: Previous Study indicated that the only way to delay spread of an epidemic is to contain the local epidemics and to prevent international travel

WHO warned today that it may be too late to prevent the spread of the swine flu that has been reported in three places in Mexico as well as California and Texas.  WHO Swine Flu Home page WHO Swine flu fact sheet  Mexico is currently conducting health screening of international air travelers.  However, that precaution, according to the Caley study published on this blog two years ago with respect to the pandemic flu threat, will be ineffective at even delaying the spread of the flu. 

The most recent news from WHO on the Stage 3 pandemic alert is WHO link.

Experts at WHO and elsewhere believe that the world is now closer to another influenza pandemic than at any time since 1968, when the last of the previous century's three pandemics occurred. WHO uses a series of six phases of pandemic alert as a system for informing the world of the seriousness of the threat and of the need to launch progressively more intense preparedness activities.  The designation of phases, including decisions on when to move from one phase to another, is made by the Director-General of WHO.  Each phase of alert coincides with a series of recommended activities to be undertaken by WHO, the international community, governments, and industry. Changes from one phase to another are triggered by several factors, which include the epidemiological behaviour of the disease and the characteristics of circulating viruses.  The world is presently in phase 3: a new influenza virus subtype is causing disease in humans, but is not yet spreading efficiently and sustainably among humans.

WHO reported this after today's Emergency Committee meeting:  

In response to cases of swine influenza A(H1N1), reported in Mexico and the United States of America, the Director-General convened a meeting of the Emergency Committee to assess the situation and advise her on appropriate responses. The establishment of the Committee, which is composed of international experts in a variety of disciplines, is in compliance with the International Health Regulations (2005). The first meeting of the Emergency Committee was held on Saturday 25 April 2009.  After reviewing available data on the current situation, Committee members identified a number of gaps in knowledge about the clinical features, epidemiology, and virology of reported cases and the appropriate responses. The Committee advised that answers to several specific questions were needed to facilitate its work. The Committee nevertheless agreed that the current situation constitutes a public health emergency of international concern.  Based on this advice, the Director-General has determined that the current events constitute a public health emergency of international concern, under the Regulations.

Concerning public health measures, in line with the Regulations the Director-General is recommending, on the advice of the Committee, that all countries intensify surveillance for unusual outbreaks of influenza-like illness and severe pneumonia.  The Committee further agreed that more information is needed before a decision could be made concerning the appropriateness of the current phase 3.

WHO currently considers this phase 3 of a pandemic. You might want to read the Global Influenza Preparedness Plan to see what happens in phase 3 and look at phase 4 and 5, which is probably where we are heading.  WHO Global Influenza Plan

From my research, the only effective measure is to contain the local epidemic and prevent international travel, especally air travel.  The occurrence of the same flu in California and Texas suggests that the Mexico flu has already escaped to the US.  Now, internal travel restrictions  within the western US and Mexico as well as international travel probably need to be implemented.  To quote the conclusion of the Caley study:

The delay until an epidemic of pandemic strain influenza is imported into an at-risk country is largely determined by the course of the epidemic in the source region and the number of travelers attempting to enter the at-risk country, and is little affected by non-pharmaceutical interventions targeting these travelers. Short of preventing international travel altogether, eradicating a nascent pandemic in the source region appears to be the only reliable method of preventing country-to-country spread of a pandemic strain of influenza.

The US and Mexico have not even advised people not to travel to Mexico, California, and Texas, much less prevented travel:

CDC has NOT recommended that people avoid travel to Mexico at this time. If you are planning travel to Mexico, follow these recommendations to reduce your risk of infection and help you stay healthy. CDC travel recommendations

In my judgment, it is irresponsible to travel into or out of these areas at this time.  I also believe the governments need to respond more strongly to what is obviously a virulent strain of communicable flu.  But, if they're doing what they are supposed to in phase 3, I admit they are probably busy.

WHO press release yesterday:

24 April 2009 -- The United States Government has reported seven confirmed human cases of Swine Influenza A/H1N1 in the USA (five in California and two in Texas) and nine suspect cases. All seven confirmed cases had mild Influenza-Like Illness (ILI), with only one requiring brief hospitalization. No deaths have been reported. The Government of Mexico has reported three separate events. In the Federal District of Mexico, surveillance began picking up cases of ILI starting 18 March. The number of cases has risen steadily through April and as of 23 April there are now more than 854 cases of pneumonia from the capital. Of those, 59 have died. In San Luis Potosi, in central Mexico, 24 cases of ILI, with three deaths, have been reported. And from Mexicali, near the border with the United States, four cases of ILI, with no deaths, have been reported.Of the Mexican cases, 18 have been laboratory confirmed in Canada as Swine Influenza A/H1N1, while 12 of those are genetically identical to the Swine Influenza A/H1N1 viruses from California.The majority of these cases have occurred in otherwise healthy young adults. Influenza normally affects the very young and the very old, but these age groups have not been heavily affected in Mexico. Because there are human cases associated with an animal influenza virus, and because of the geographical spread of multiple community outbreaks, plus the somewhat unusual age groups affected, these events are of high concern. The Swine Influenza A/H1N1 viruses characterized in this outbreak have not been previously detected in pigs or humans. The viruses so far characterized have been sensitive to oseltamivir, but resistant to both amantadine and rimantadine.

The World Health Organization has been in constant contact with the health authorities in the United States, Mexico and Canada in order to better understand the risk which these ILI events pose. WHO (and PAHO) is sending missions of experts to Mexico to work with health authorities there. It is helping its Member States to increase field epidemiology activities, laboratory diagnosis and clinical management. Moreover, WHO's partners in the Global Alert and Response Network have been alerted and are ready to assist as requested by the Member States.  WHO acknowledges the United States and Mexico for their proactive reporting and their collaboration with WHO and will continue to work with Member States to further characterize the outbreak.

CDC Information: CDC link - Human Swine Influenza Investigation

April 25, 2009 1:00 p.m. ET

Human cases of swine influenza A (H1N1) virus infection have been identified in the U.S. in San Diego County and Imperial County, California as well as in San Antonio, Texas. Internationally, human cases of swine influenza A (H1N1) virus infection have been identified in Mexico.

U.S. Human Cases of Swine Flu Infection
State # of laboratory
confirmed cases
California 6 cases
Texas 2 cases
International Human Cases of Swine Flu Infection
See: World Health OrganizationExternal Web Site Policy.
As of April 25th, 2009 11:00 a.m. ET

Investigations are ongoing to determine the source of the infection and whether additional people have been infected with similar swine influenza viruses.

CDC is working very closely with state and local officials in California, Texas, as well as with health officials in Mexico, Canada and the World Health Organization. On April 24th, CDC deployed 7 epidemiologists to San Diego County, California and Imperial County, California and 1 senior medical officer to Texas to provide guidance and technical support for the ongoing epidemiologic field investigations. CDC has also deployed to Mexico 1 medical officer and 1 senior expert who are part of a global team that is responding to the outbreak of respiratory illnesses in Mexico.

Influenza is thought to spread mainly person-to-person through coughing or sneezing of infected people. There are many things you can to do preventing getting and spreading influenza:

There are everyday actions people can take to stay healthy.

  • Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
  • Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hands cleaners are also effective.
  • Avoid touching your eyes, nose or mouth. Germs spread that way.

Try to avoid close contact with sick people.

  • Influenza is thought to spread mainly person-to-person through coughing or sneezing of infected people.
  • If you get sick, CDC recommends that you stay home from work or school and limit contact with others to keep from infecting them.

Topics on this page:

General Information

Swine Flu and You
What is swine flu? Are there human infections with swine flu in the U.S.? …

Swine Flu Video Podcast
Dr. Joe Bresee, with the CDC Influenza Division, describes swine flu - its signs and symptoms, how it's transmitted, medicines to treat it, steps people can take to protect themselves from it, and what people should do if they become ill.

Key Facts about Swine Influenza (Swine Flu)
How does swine flu spread? Can people catch swine flu from eating pork? …

Swine Influenza in Pigs and People
Brochure

Information in Spanish
Datos importantes sobre la influenza porcina…

Summary Guidance

CDC has provided the following interim guidance for this investigation.

Residents of California and Texas

CDC has identified human cases of swine influenza A (H1N1) virus infection in people in these areas. CDC is working with local and state health agencies to investigate these cases. We have determined that this virus is contagious and is spreading from human to human. However, at this time, we have not determined how easily the virus spreads between people. As with any infectious disease, we are recommending precautionary measures for people residing in these areas.

  • Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
  • Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hands cleaners are also effective.
  • Try to avoid close contact with sick people.
  • If you get sick, CDC recommends that you stay home from work or school and limit contact with others to keep from infecting them.
  • Avoid touching your eyes, nose or mouth. Germs spread that way.

There is no vaccine available at this time, so it is important for people living in these areas to take steps to prevent spreading the virus to others. If people are ill, they should attempt to stay at home and limit contact with others. Healthy residents living in these areas should take everyday preventive actions.

People who live in these areas who develop an illness with fever and respiratory symptoms, such as cough and runny nose, and possibly other symptoms, such as body aches, nausea, or vomiting or diarrhea, should contact their health care provider. Their health care provider will determine whether influenza testing is needed.

Clinicians

Clinicians should consider the possibility of swine influenza virus infections in patients presenting with febrile respiratory illness who:

  1. Live in San Diego County or Imperial County, California or San Antonio, Texas or
  2. Have traveled to San Diego and/or Imperial County, California or San Antonio, Texas or
  3. Have been in contact with ill persons from these areas in the 7 days prior to their illness onset.

If swine flu is suspected, clinicians should obtain a respiratory swab for swine influenza testing and place it in a refrigerator (not a freezer). Once collected, the clinician should contact their state or local health department to facilitate transport and timely diagnosis at a state public health laboratory.

State Public Health Laboratories

Laboratories should send all unsubtypable influenza A specimens as soon as possible to the Viral Surveillance and Diagnostic Branch of the CDC’s Influenza Division for further diagnostic testing.

Public Health /Animal Health Officials

Officials should conduct thorough case and contact investigations to determine the source of the swine influenza virus, extent of community illness and the need for timely control measures.

Guidance Documents

Swine Influenza A (H1N1) Virus Biosafety Guidelines for Laboratory Workers Apr 24, 2009
This guidance is for laboratory workers who may be processing or performing diagnostic testing on clinical specimens from patients with suspected swine influenza A (H1N1) virus infection, or performing viral isolation.

Interim Guidance for Infection Control for Care of Patients with Confirmed or Suspected Swine Influenza A (H1N1) Virus Infection in a Healthcare Setting Apr 24, 2009

Interim Guidance on Case Definitions for Swine Influenza A (H1N1) Human Case Investigations Apr 24, 2009
This document provides interim guidance for state and local health departments conducting investigations of human cases of swine influenza A (H1N1) virus.  The following case definitions are for the purpose of investigations of suspected, probable, and confirmed cases of swine influenza A (H1N1) virus infection.

Travel Notices

Outbreak Notice: Swine Influenza in the United States
April 25, 2009 12 p.m. ET

Travel Health Precaution: Swine Influenza and Severe Cases of Respiratory Illness in Mexico
April 25, 2009 12 p.m. ET

Transcripts

Unedited Transcript of CDC Briefing on Public Health Investigation of Human Cases of Swine Influenza
April 24, 2009 2:30 p.m. ET

CDC Briefing on Public Health Investigation of Human Cases of Swine Influenza
April 23, 2009 press briefing…

Reports & Publications

Update: Swine Influenza A (H1N1) Infections --- California and Texas, April 2009
Morbidity and Mortality Weekly Report (MMWR) April 24, 2009 / Vol. 58 / Dispatch;1-3

Swine Influenza A (H1N1) Infection in Two Children – Southern California, March—April 2009
Morbidity and Mortality Weekly Report (MMWR) April 21, 2009 / Vol. 58 / Dispatch

Related Links

WHO - Influenza-Like Illness in the United States and MexicoExternal Web Site Policy.

Past Updates

Caley study:

Bird Flu Blues: Source Country Suppression is the Only Viable Means to Prevent the International Transmission of Pandemic Strains

Peter Caley , Niels Becker, and David Philp of the National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia have modelled the impacts of various pandemic preparedness efforts on the timing of international spread of pandemic strains.  The bottom line is that "[s]hort of preventing international travel altogether, eradicating a nascent pandemic in the source region appears to be the only reliable method of preventing country-to-country spread of a pandemic strain of influenza."PLoSOne link The entire article is available courtesy of a Creative Commons license:

Background

The time delay between the start of an influenza pandemic and its subsequent initiation in other countries is highly relevant to preparedness planning. We quantify the distribution of this random time in terms of the separate components of this delay, and assess how the delay may be extended by non-pharmaceutical interventions.

Methods and Findings

The model constructed for this time delay accounts for: (i) epidemic growth in the source region, (ii) the delay until an infected individual from the source region seeks to travel to an at-risk country, (iii) the chance that infected travelers are detected by screening at exit and entry borders, (iv) the possibility of in-flight transmission, (v) the chance that an infected arrival might not initiate an epidemic, and (vi) the delay until infection in the at-risk country gathers momentum. Efforts that reduce the disease reproduction number in the source region below two and severe travel restrictions are most effective for delaying a local epidemic, and under favourable circumstances, could add several months to the delay. On the other hand, the model predicts that border screening for symptomatic infection, wearing a protective mask during travel, promoting early presentation of cases arising among arriving passengers and moderate reduction in travel volumes increase the delay only by a matter of days or weeks. Elevated in-flight transmission reduces the delay only minimally.

Conclusions

The delay until an epidemic of pandemic strain influenza is imported into an at-risk country is largely determined by the course of the epidemic in the source region and the number of travelers attempting to enter the at-risk country, and is little affected by non-pharmaceutical interventions targeting these travelers. Short of preventing international travel altogether, eradicating a nascent pandemic in the source region appears to be the only reliable method of preventing country-to-country spread of a pandemic strain of influenza.

Introduction

The emergence of a pandemic strain of influenza is considered inevitable [1]. Provided the emerged strain is not too virulent, it may be possible to eliminate a nascent influenza pandemic in the source region via various combinations of targeted antiviral prophylaxis, pre-vaccination, social distancing and quarantine [2], [3]. If early elimination in the source region is not achieved, then any delay in a local epidemic that a country can effect will be highly valued. To this end, countries may consider introducing non-pharmaceutical interventions such as border screening, promoting early presentation of cases among arriving passengers, requiring the use of personal protective equipment during travels (e.g. the wearing of masks), and reducing traveler numbers. While the case for believing that measures such as these can not stop the importation of an epidemic from overseas has been argued strongly, whether it be SARS or influenza [4][6], the extent to which such interventions delay a local epidemic is currently not well quantified, and hence of considerable interest.

In this paper we demonstrate how the delay to importation of an epidemic of pandemic strain influenza may be quantified in terms of the growing infection incidence in the source region, traveler volumes, border screening measures, travel duration, in-flight transmission and the delay until an infected arrival initiates a chain of transmission that gathers momentum. We also investigate how the delay is affected by the reproduction number of the emerged strain, early presentation of cases among arriving passengers, and reducing traveler numbers. As noted in previous simulation modeling [7], many aspects of this delay have a significant chance component, making the delay a random variable. Therefore, the way to quantify the delay is to specify its probability distribution, which we call the delay-distribution.

Some issues of the delay distribution, such as the natural delay arising in the absence of intervention and the effect that reducing traveler numbers has on this delay has been studied previously [6][8]. Specifically, if the originating source is not specified, and homogeneous mixing of the worlds population is assumed, then the most likely time to the initial cases arising in the United States is about 50 days assuming R             0 = 2.0 [7]. The additional delay arising from travel restrictions appears minimal until a>99% reduction in traveler numbers [6][8].

This paper adds to previous work [5][8] by simultaneously including a wider range of epidemiological factors and possible interventions, such as elevated in-flight transmission, flight duration, the effect of wearing of mask during flight, early presentation of cases among travelers, and quarantining all passengers from a flight with a detected case at arrival.

Methods

General

Consider a region in which a new pandemic strain of influenza has emerged, and a region currently free from the infection. We refer to these as the source region and the at-risk country, respectively. Travel between these countries is predominantly via commercial air travel and/or rapid transport which could potentially be subject to border screening and other interventions. We restrict our discussion to air travel. The aim is to assess the effects that a variety of non-pharmaceutical border control measures have, individually and in combination, on the time it takes before the epidemic takes off in the at-risk country. An epidemic is said to have “taken off” when it reaches 20 current infectious cases, after which its growth is highly predictable (i.e. nearly deterministic) and the probability of fade-out by chance is very low, if intervention is not enhanced. The source country of origin will undoubtedly have a large impact on the natural delay until importation of an epidemic, although this is difficult to quantify [7]. An alternative is to fix the originating city, for example a highly connected city such as Hong Kong [6], with the obvious effect that results are highly dependent on the choice. We adopt no specific source region, but assume that the number of international travelers originating from it is reasonably small (see Methods), suggestive of a rural or semi-rural source region [2]. It is further assumed that the current heightened surveillance for pandemic influenza is continued and that a nascent pandemic with human-to-human transmission is identified and the pandemic is declared when there are 10 concurrent cases in the source region.

For an epidemic to take off in an at-risk country, a series of events need to occur. First, the epidemic needs to get underway in the source region. Second, an intending traveler needs to be infected shortly before departure. Third, the infected traveler must actually travel and successfully disembark in the at-risk country. Fourth, the infected traveler, or fellow travelers infected during the flight, must initiate an epidemic in the at-risk country with the infectiousness that remains upon arrival. Finally, the epidemic needs to reach a sufficient number of cases to begin predictable exponential growth.

Infected travelers

International spread of the emerged pandemic strain of influenza may occur when a recently infected person travels. By ‘recently infected’ we mean that their travel is scheduled to occur within ten days of being infected. We assume that the number of individuals traveling from the source region to the at-risk country each day is known. The probability that a randomly selected traveler is a recently-infected person is taken to be equal to the prevalence of recently-infected people in the source region on that day. The incidence of infection in the source region is assumed to grow exponentially initially, with the rate of exponential growth determined by the disease reproduction number (the mean number of cases a single infective generates by direct contact) and the serial interval (the average interval from infection of one individual to when their contacts are infected) (Figure 1A).

thumbnail
Figure 1.  

The process through which a pandemic is imported. (A) The prevalence in the source region, which determines the probability that a randomly selected traveler is infected at scheduled departure. (B)–(D) Density functions of the time since infection during the early stages of the epidemic in the source region for infected travelers (B) before and (C) after departure screening, and (D) after arrival screening for clinical symptoms. In (B), the step illustrates the probabilistic removal of travelers who have completed their incubation period. In (D), the distribution of time since infection in (C) will have shifted to the right by an amount equal to the flight duration, and cases incubated in-flight may be detected by symptomatic screening, as will those symptomatic cases that were not detected previously. Screening sensitivity for this illustration is 60% on both departure and arrival. (E) Upon entering the community undetected, an infected traveler may initiate a minor (inconsequential) or major epidemic, depending on the characteristics of the disease and public health policy.

doi:10.1371/journal.pone.0000143.g001

The time since infection of a recently-infected traveler is a key component of the calculations, because it affects the chance of positive border screening, the chance of in-flight transmission and the infectivity remaining upon arrival in the at-risk country. The time since infection at the time of scheduled departure is random and the dependence of its probability distribution on the exponential growth rate of infection is illustrated by Figure 1B (see also Supporting Information). The higher the epidemic growth rate in the source region, the greater the probability than an infected traveler will have been infected more recently.

Traveler screening at departure

It is assumed that individuals detected by departure screening are prevented from traveling. To be detected by screening an infected traveler must be symptomatic and positively screened. An individual is assumed to become symptomatic 48 hours after being infected (cf. [3] who use 1.9 days). The probability of being symptomatic when presenting for departure screening is computed from the curve in Figure 1B. The distribution of the time since infection immediately after departure screening, given that the infected traveler was not detected, is given by the curve in Figure 1C. It contains an adjustment for the probability of being detected at departure.

In-flight transmission

The instantaneous rate at which susceptible contacts are infected depends on the time since infection, and is described by an infectiousness function ([9], page 45). We use a peaked infectiousness function, motivated by viral shedding and household transmission data [2], which has a serial interval of 2.6 days. The basic reproduction number (R                0), namely the reproduction number when there is no intervention in place and every contacted individual is susceptible, is given by the area under the infectiousness function. However, our concern is with the effective reproduction number R that holds when various interventions are in place. We obtain any R by simply multiplying the infectiousness function by the appropriate constant (to make the area under the curve equal to R). This keeps the serial interval the same. In the absence of suitable data we assume for most scenarios that the aircrafts ventilation and filtration systems are functioning properly, and that infected travelers transmit the infection at the same rate during a flight as they would while mixing in the community. We examine the sensitivity of this assumption by increasing the in-flight transmission by as much as 10-fold (as could potentially happen if air-circulation and filtration systems malfunction, e.g. see [10]). The in-flight transmission rate is set to zero under the optimistic scenario that all travelers wear 100% effective masks during transit. In terms of a sensitivity analysis this illustrates what would be achievable in a best-case scenario. The number of offspring that an infected traveler infects during a flight is a random variable, taken to have a Poisson distribution with a mean equal to the area under the infectiousness function over to the flight duration.

Traveler screening at arrival

Travelers infected during flights of less than 12 hours duration are asymptomatic at arrival and will not be detected by screening. The probability that an arriving traveler who was infected in the source region is detected on arrival is computed from the distribution of the time since infection on arrival. This distribution is obtained from the curve in Figure 1C by shifting it to the right by an amount equal to the duration of the flight. The distribution of the time since infection for an individual infected in the source region, who passes through arrival screening undetected has a further adjustment for the chance of being detected at arrival (Figure 1D). This curve shows that an infected traveler who escapes detection at departure and arrival is highly likely to enter the at-risk country with most, or all, of their infectious period remaining.

Authorities are assumed to implement one of two control options when detecting an infected traveler by arrival screening. Under option one (individual-based removal), all passengers who test negative are released immediately and only passengers who test positive are isolated. Under the second option (flight-based quarantining), authorities prevent all passengers from dispersing into the community until the last person has been screened from that flight. Should any one passenger be detected as infected then all passengers will be quarantined, as previously recommended [5].

Transmission chains initiated by infected arrivals

Transmission chains can be initiated in the at-risk country by infected travelers who mix within the community upon arrival. Suppose now that a flight arrives with one, or more, infected passengers who mix within the community. We classify these infected arrivals into those who are ‘pre-symptomatic’ and those who are ‘symptomatic’ at entry. It is assumed that the ‘symptomatic’ infected arrivals do not recognize their symptoms as pandemic influenza and will not present to medical authorities. In other words, they spend the remainder of their infectious period mixing in the community. On the other hand, the ‘pre-symptomatic’ infected arrivals, including all individuals infected during flight, are assumed to mix freely in the community only from entry until they present to medical authorities after some delay following the onset of symptoms.

Probability that an undetected infected traveler initiates a major epidemic

Not all infected travelers entering the community initiate a ‘major’ epidemic, even when the reproduction number (R) exceeds one. Quite generally, the distribution of the size of an epidemic initiated by an infected arrival is bimodal, with distinct peaks corresponding to a major epidemic and a minor outbreak (Figure 1E). In the latter event the outbreak simply fades out by chance despite there being ample susceptibles in the population for ongoing transmission [11]. The number of cases in an outbreak that fades out is typically very small compared to an epidemic.

The probability that a typical infective generates a local epidemic is computed by using a branching process approximation [12] for the initial stages of the epidemic, and equating ‘epidemic’ with the event that the branching process does not become extinct. This calculation is well known (e.g. [13], page 473), but is modified here to allow for the fact that the process is initiated by a random number of infected arrivals and some of them have spent a random part of their infectious period before arriving in the at-risk country. The distribution for the random number of individuals infected by an infected individual when all their contacts are with susceptible individuals is needed for the calculation. The lack of data prevents a definitive conclusion for the most appropriate offspring distribution for influenza transmission [14], and we use a Poisson distribution with a mean equal to R, discounted for individuals who spent only some of their infectious period mixing in the at-risk country. A Poisson offspring distribution is appropriate when the area under the infectiousness function is non-random (i.e. all individuals have the same infection ‘potential’). We assume that R is the same in the source region and the at-risk country. For an undetected infected traveler and all their in-flight offspring to fail to initiate an epidemic on arrival, all of the chains of transmission they initiate must fail to become large epidemics (see Supporting Information).

The delay until an epidemic gathers momentum in the at-risk country

We calculate the probability distribution of D, the total delay until an epidemic gathers momentum by noting that it is given by D = D                1+D                2, where D                1 is the time until an epidemic is first initiated and D                2 is the time from initiation until the local epidemic gathers momentum. For an epidemic to be first initiated in the at-risk country on day d, it must have not been initiated on all previous days. Hence the probability distribution of the time delay (D                1) until the epidemic is first initiated in the at-risk country following identification in the source region is described by:

                                  
where pd                 denotes the probability that the epidemic is initiated on day d , and                                    denotes the probability that the epidemic is not initiated on day d (see Supporting Information for calculation of pd                ).

Once successfully initiated, an epidemic may initially hover around a handful of cases before reaching a sufficient number of cases for its growth to become essentially predictable. As mentioned, 20 concurrent cases is our criterion for an epidemic to have gathered momentum. We determine the distribution of D                2, the time to this occurrence, from 10,000 stochastic simulations and approximate this empirical distribution by a shifted gamma distribution. Our criterion of 20 concurrent cases is conservatively high, as results from the theory of branching processes shows that the probability of a minor epidemic (and hence no take-off) starting from 20 concurrent cases is about 3×10−8 when R = 1.5, and even smaller for higher values of R. Finally, the distribution of the total delay (D = D                1+D                2) from the pandemic being identified in the source region until 20 cases in the at-risk country was calculated by the convolution of the distributions of D                1 and D                2.

Parameter values

For the illustrative purposes, we chose values of 1.5, 2.5 and 3.5 for R, which encompass estimates proposed for previous pandemics [2], [3], [15]. The number of people within the infected source region was assumed reasonably small (5 million), and there was one flight per day traveling from the source region to the at-risk country carrying 400, 100 or 10 passengers. A higher number of travelers affects the delay only marginally, assuming the epidemic takes off in the source region (see Results). We assume a typical travel duration between attempted departure and possible arrival of 12 hours, but also examine the effect of varying this from 0–48 hours. The time to presentation following symptom onset is varied from ‘immediately’ to ‘never presenting’, with a time of 6 hours considered likely in the presence of an education campaign. The sensitivity of symptomatic screening is varied from 0–100%, with results presented for 0, 50 and 100% sensitivity.

Results

Evading traveler screening

The probability that a recently infected traveler evades screening is substantial even if screening reliably detects symptomatic travelers (Figure 2A), because the typical travel duration is shorter than the 2-day incubation period. In addition, during the early stages of the epidemic a high R in the source region acts to increase the probability that an infected traveler has been infected quite recently and hence will escape detection due to being asymptomatic during their travels (Figure 2A). For example, assuming 100% sensitivity for detecting symptomatic infection, we calculate that during the early stages of the epidemic the proportion of infected travelers that evade both departure and arrival screening after 12 hours of travel is 0.26, 0.45 and 0.59 for disease reproduction numbers 1.5, 2.5 and 3.5, respectively.

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Figure 2.  

Effects of border screening and early presentation. (A) The effects of screening sensitivity andon the probability of escaping detection on both departure and arrival during a 12 hour transit. (B) The effects of screening sensitivity and travel duration on the probability than an infected traveler escapes detection during transit and initiates an epidemic after arrival (assuming no other symptomatic individuals on the same flight are identified). R = 3.5 with no early presentation. (C) The effects of R and the time from symptom onset to presentation on the probability that an infected traveler, having entered the wider community following arrival, will initiate an epidemic. There is no screening.

doi:10.1371/journal.pone.0000143.g002

As the duration of travel approaches the disease incubation period, effective symptomatic screening substantially reduces the likelihood that a traveler evades screening and initiates an epidemic (Figure 2B). Reducing the time from the onset of symptoms to presentation (and subsequent isolation) for each infected arrival also reduces the probability that a major epidemic is initiated, however the best case scenario of infected travelers and all their in-flight offspring presenting immediately following the onset of symptoms still poses a substantial risk of epidemic initiation arising from pre-symptomatic transmission (Figure 1C).

The time until an epidemic gathers momentum in the at-risk country

The delay contains a fairly substantial natural component, primarily due to the time it takes to increase the number of infectives in the source region sufficiently to make the chance of a recently infected traveler appreciable (Figure 3A), and the time (D                2) it takes for a local epidemic in the at-risk country to gather momentum following successful seeding (Figure 4A). In the absence of any interventions, the number of infected individuals who successfully enter the community of the at-risk country initially increases exponentially (Figure 3A). With individual-based removal of infected travelers, the number of individuals entering the at-risk country undetected by screening is proportionately reduced over the course of the epidemic (Figure 3A). With flight-based quarantining, the number of infected individuals entering the at-risk country undetected is dramatically reduced over the course of the epidemic, even for relatively insensitive screening (Figure 3A). With flight-based quarantining, the number of infected passengers slipping through undetected is bimodal, with the first peak occurring when the number of infected travelers attempting to travel is still in single figures.

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Figure 3.  

Components of delay until initiation and effects of border screening. (A) The number of infected people successfully arriving and entering the community of an at-risk country (KA                      ) on each day following the identification of an outbreak of pandemic type strain influenza, assuming a source region population of 5 million, 400 intending travelers per day, R = 1.5, and three levels of symptomatic screening (solid line = nil, dashed line = 50% sensitivity with individual-based removal, dotted line = 50% sensitivity with flight-based quarantining). (B) Corresponding daily probability of initiation (pd                      ) as a function of time since pandemic identified. (C) Distribution of the delay time until the initiation (D                      1) of an epidemic in an at-risk country by an infected traveler from a source region.

doi:10.1371/journal.pone.0000143.g003
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Figure 4.  

Components of the delay in at-risk country following initiation. (A) Results of 10,000 simulations (bars) and fitted shifted-Gamma distribution of delay time (D                      2) until 20 concurrent cases occur in the at-risk country, given that an epidemic has been initiated, andequals 1.5 with a serial interval of 2.6 days. (B) The total delay distribution until there are 20 concurrent cases in the at-risk country from when a pandemic type strain of influenza outbreak is identified in a source region with a population of 5 million, 400 intending travelers day−1, an R of 1.5, and three levels of symptomatic screening (solid line = nil, dashed line = 50% sensitivity with individual removal, dotted line = 50% sensitivity with flight-based quarantining).

doi:10.1371/journal.pone.0000143.g004

Without screening, the daily probability that an epidemic is initiated (pd                ) increases, and becomes near certain once the number of infected travelers arriving undetected exceeds about 10 (Figure 3B, solid line). With screening and individual-based removal of infected individuals, pd                 follows a similar pattern only reduced somewhat. With screening in combination with flight-based quarantining, this probability is changed dramatically. After an initial rise it dips, to become essentially zero during the height of the epidemic in the source region (Figure 3B, dotted line). This arises because once a flight has several infected travelers, the probability that at least one is detected approaches one (even if screening is imperfect), and all passengers on such a flight are quarantined. Once the epidemic starts to wane in the source region (assuming the unlikely event of the pandemic strain is restricted to the source region), the probability of initiation rises once again. The corresponding distribution of D                1, the delay until the epidemic is first initiated in the at-risk country, is bi-modal in the presence of screening (Figure 3C).

Although flight-based quarantining is effective in preventing the entry of infected travelers during the height of the epidemic, a substantial cumulative risk of initiation has already occurred before this from the handful of infectives that have slipped through undetected (Figure 3B). Hence, whilst the effect of border screening, particularly in conjunction with flight-based quarantining, on the daily probability of initiation is dramatic, its effect on the delay to initiation is much less pronounced (Figure 3C). Border screening, even with perfect sensitivity for detecting symptomatic cases, tends to increase D                1, the time to an epidemic being initiated, by a matter of days to weeks. The time (D                2) from initiation (the arrival of the index case) to an epidemic reaching 20 concurrent cases within the at-risk country is adequately modeled using a shifted Gamma distribution (Figure 4A). The convolution of this right-skewed Gamma distribution with the left-skewed delay-distribution of D                1 (Figure 3C) yields the distribution for D, the total delay until the epidemic reaches 20 cases in the at-risk country (Figure 4B). The distribution of D is approximately symmetrical. The effect of border screening on the total delay D is quite modest, though sensitive to how screening is implemented. For example, with R = 1.5 and 400 travelers per day, 100% sensitive screening with individual-based removal increases the median delay from 57 to 60 days (Figure 4B). Flight-based quarantining would extend the median delay to 70 days. In general, the added delay arising from flight-based quarantining is about four-fold that arising from individual-based removal.

The natural component of the delay is highly sensitive to the disease reproduction number (Figure 5A). For example, with 400 passengers per day departing the source country and in the absence of any interventions, the median delay ranges from a low of 17 days for R = 3.5 to 57 days for R = 1.5 (Table 1). The delay is less sensitive to the number of intending travelers, with little appreciable increase in the median delay occurring until traveler numbers become very low (Figure 5B). For example, if R = 1.5, with no other border control measures, decreasing the number of intending travelers departing the source region from 400 to 100 per day increases the median total delay D from 57 to 66 days. A further decrease in the number of intending travelers to 10 per day increases the median delay to 83 days (Table 1).

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Figure 5.  

Effects of interventions on the total delay D. (A) The effects of R on delay-distribution. (B) The effects of daily traveler number on the median delay for different values of R. (C) The effects of the time from symptom incubation until presentation and isolation (tSP                      ) on the delay-distribution. (D) Additive effects of implementing 100% sensitive border screening (individual removal), the wearing of masks during transit, immediate presentation following symptom onset, and flight-based quarantining on the median delay, assuming 400 travelers per day attempting to depart the source region.

doi:10.1371/journal.pone.0000143.g005
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Table 1. Summary measures of the expected time until an epidemic of pandemic strain influenza in an at-risk country reaches 20 cases, for three values of R and three values for the number of intending travelers when the source region contains 5 million people.
doi:10.1371/journal.pone.0000143.t001

The delay is quite insensitive to the rate of transmission in-flight. For example, with R = 1.5, a 12-hour flight, 400 travelers per day and no other interventions, preventing in-flight transmission altogether increases the median delay from 57 to 58 days. Conversely, doubling the rate of in-flight transmission reduces the median delay from 57 to 56 days. A 10-fold increase in the rate of transmission in-flight only decreases the median delay from 57 to 53 days. Encouraging the early presentation of cases among travelers following the onset of symptoms has a limited effect on the delay distribution (Figure 5C). For example, for R = 1.5, 400 intending travelers per day and no other interventions, reducing the time to presentation from ‘never presenting’ to 6 hours increases the median delay from 57 to 61 days. Immediate presentation at symptom onset only increases the median delay a further day in this scenario.

In general, the additional delay achieved by introducing non-pharmaceutical border control measures is generally small in comparison with the natural delay (Figure 5D). For the scenario with R = 1.5 and 400 intending travelers per day, a combination of 100% flight-based quarantining, 100% compliance with mask wearing during travel and immediate presentation at symptom onset extends the estimated median delay from 57 to 79 days (Figure 5D). This added delay diminishes in absolute terms as R increases. For example, if the same interventions are applied with R = 3.5, the median delay is extended from 17 to just 20 days (Figure 5D). The one exception to this generalisation is when travel numbers are reduced dramatically. The added delay achieved when a drastic reduction in travel numbers is combined with other border control measures appears to be greater than adding the delays each achieves on its own. For example, if R = 1.5, and we reduce the number of intending travelers from 400 to 10 per day, implement 100% flight-based quarantining, implement compulsory mask wearing during travel and presentation at 6 hours following symptom onset then there is a substantial probability (0.74) that the pandemic strain will never be imported (assuming the epidemic is confined to the source country). The estimated quartile delay (the median in this case is undefined) to the start of a major epidemic in an at-risk country is extended from 50 to 125 days. Again, the added delay decreases rapidly as R increases, and if the above interventions were applied with R = 3.5, the estimated median delay is extended from 17 to 26 days, and the importation of the epidemic is certain (Figure 5D).

Discussion

We have formulated a model of the importation of an infectious disease from a source region to an at-risk country that permits a comprehensive analysis of the effect of border control measures. Our results are most relevant to the early stage of a pandemic when most cases are contained within a single source region. Once the pandemic has spread to several countries, models with greater complexity and ability to more realistically model global mixing patterns [6][8] are required. Our model is developed with a pandemic-strain of influenza in mind, but could apply to any emerging infectious disease that is transmitted from person to person. We have assumed a Poisson distribution for the number of secondary infections, which a natural choice when each infected individual has the same infectivity profile. A distribution with a larger variance is appropriate when individuals vary substantially in their infectiousness. Our results are conservative in the sense that they give an upper bound for the probability that an infected traveler manages to initiate an epidemic, compared to an offspring distribution with a greater variance but the same reproduction number [14].

The nature of the next pandemic influenza virus, and particularly its reproduction number, is uncertain. If its reproduction number is low (R<2.0), our results indicate that at-risk countries receiving a reasonably small number of travelers (say 400 per day) from the infected source region can expect a natural delay until importing an epidemic of the order of 2 months. This is quite variable and under favourable conditions it could be 4 months. However, the natural delay decreases rapidly as R increases.

The additional delay from isolating individuals detected by border screening is merely a few days under most plausible scenarios, even if both departure and arrival screening is introduced and screening detects every symptomatic traveler. While the extra delay is more than quadrupled if flights with a detected case(s) are quarantined, the effect remains modest (weeks at most) and it is questionable whether the extra delay achieved warrants the disruption created by such a large number of quarantined passengers.

In-flight transmission is a commonly raised concern in discussions about the importation of an infection, so inclusion of in-flight transmission is an attractive feature of our model. Events of substantial in-flight transmission of influenza have been documented [10], [16] and modeling of indoor airborne infection risks in the absence of air filtration predicts that in-flight transmission risks are elevated [17]. However, it difficult to estimate the infectiousness of influenza in a confined cabin space, as there is undoubtedly substantial under-reporting of influenza cases who travel and fail to generate any offspring during flight. Provided the aircraft ventilation system (including filtration) is operational, it is considered that the actual risk of in-flight transmission is much lower than the perceived risk [18]. Our results indicate that the delay is relatively insensitive to the rate of in-flight transmission, making in-flight transmission less of an issue than commonly believed. A highly elevated transmission rate in-flight will hasten the importation of an epidemic only marginally. Consistent with this, eliminating in-flight transmission by wearing protective masks increases the delay only marginally.

Early presentation by infected arrivals not detected at the borders was found to add only a few days to the delay. To some extent this arises due to our assumption that pre-symptomatic transmission can occur, for which there is some evidence. In contrast, Ferguson et al. [2] assume that the incubation and latent periods are equal, with a mean of 1.5 days. In their model pre-symptomatic transmission is excluded and infectiousness is estimated to spike dramatically immediately following symptom onset and declining rapidly soon afterwards. Under their model assumptions, immediate presentation at onset of symptoms would reduce transmission effectively. However, as presentation occurs some time after onset of symptoms and the bulk of infectivity occurs immediately after onset of symptoms the results on the effect of early presentation of cases are likely, in practical terms, to be similar to those found here. Given the variable nature of influenza symptoms, there is likely to be a difference between the onset of the first symptoms as measured in a clinical trial (e.g. [19]) and the time that a person in the field first suspects that they may be infected with influenza virus. To fully resolve the issue of how effective very early presentation of infected travelers is in delaying a local epidemic we need better knowledge about the infectiousness of individuals before and just after the onset of symptoms.

Of the border control measures available, reducing traveler numbers has the biggest effect on the delay and even then it is necessary to get the number of travelers down to a very low number. An equivalent control measure is to quarantine all arriving passengers with near perfect compliance.

Our results indicate that short of virtually eliminating international travel, border control measures add little to avoiding, or delaying, a local epidemic if an influenza pandemic takes off in a source region. All forms of border control are eventually overwhelmed by the cumulative number of infected travelers that attempt to enter the country. The only way to prevent a local epidemic is to rapidly implement local control measures that bring the effective reproduction number in the local area down below 1, or to achieve rapid elimination in the source region, in agreement with other recent studies [6][8]. Preventing the exponential growth phase of an epidemic in the source region appears to be the only method able to prevent a nascent influenza pandemic reaching at-risk countries.

Supporting Information

Text S1.

Estimating the daily probability of epidemic initiation

(0.08 MB PDF)

Acknowledgments

We thank James Wood, Katie Glass and Belinda Barnes and an anonymous reviewer for helpful comments.

Author Contributions

Conceived and designed the experiments: NB PC. Performed the experiments: PC DP. Analyzed the data: NB PC DP. Contributed reagents/materials/analysis tools: PC DP. Wrote the paper: NB PC.

References

  1. Germann TC, Kadau K, Longini IM, Macken CA. (2006) Mitigation strategies for pandemic influenza in the United States. Proceedings of the National Academy of Science 103: 5935–5940. Find this article online
  2. Ferguson NM, Cummings DAT, Cauchemez S, Fraser C, Riley S, et al. (2005) Strategies for containing an emerging influenza pandemic in Southeast Asia. Nature  437: 209214. Find this article online
  3. Longini IM, Nizam A, Xu S, Ungchusak K, Hanshoaworakul W, et al. (2005) Containing pandemic influenza at the source. Science  309: 1083–1087. Find this article online
  4. John RK St, King A, de Jong D, Bodie-Collins M, Squires SG, et al. (2005) Border screening for SARS. Emerging Infectious Diseases  11: 6–10. Find this article online
  5. Pitman RJ, Cooper BS, Trotter CL, Gay NJ, Edmunds WJ. (2005) Entry screening for severe acute respiratory syndrome (SARS) or influenza: policy evaluation. British Medical Journal 331: 1242–1243. Find this article online
  6. Cooper BS, Pitman RJ, Edmunds WJ, Gay NJ. (2006) Delaying the international spread of pandemic influenza. PloS Medicine  3: e212. Find this article online
  7. Ferguson NM, Cummings DAT, Fraser C, Cajka JC, Cooley PC, et al. (2006) Strategies for mitigating an influenza pandemic. Nature  442: 448–452. Find this article online
  8. Hollingsworth TD, Ferguson NM, Anderson RM. (2006) Will travel restrictions control the international spread of pandemic influenza? Nature Medicine  12: 497–499. Find this article online
  9. Becker NG (1989) Analysis of Infectious Disease Data. London: Chapman and Hall. 
  10. Moser MR, Bender TR, Margolis HS, Noble GR, Kendal AP, et al. (1979) An outbreak of influenza aboard a commercial airline. American Journal of Epidemiology  110: 1–6. Find this article online
  11. Lloyd-Smith JO, Cross PC, Briggs CJ, Daugherty M, Getz WM, et al. (2005) Should be expect population thresholds for wildlife disease? Trends in Ecology and Evolution  20: 511–519. Find this article online
  12. Harris TE (1963) The Theory of Branching Processes. Berlin: Springer. 230 p p. 
  13. Caswell H (2000) Matrix Population Models: Construction, Analysis, and Interpretation. Sunderland, , Massachusetts: Sinauer Associates, Inc. 727 p p.
  14. Lloyd-Smith JO, Schreiber SJ, Kopp PE, Getz WM. (2005) Superspreading and the effect of individual variation on disease emergence. Nature  438: 355–359. Find this article online
  15. Mills CE, Robins JM, Lipsitch M. (2004) Transmissibility of 1918 pandemic influenza. Nature  432: 904–906. Find this article online
  16. Marsden AG. (2003) Influenza outbreak related to air travel. The Medical Journal of Australia  179: 172–173. Find this article online
  17. Liao C, Chang C, Liang H. (2005) A probabilistic transmission dynamic model to assess indoor airborne infection risks. Risk Analysis  25: 1097–1107. Find this article online
  18. Mangili A, Gendreau MA. (2005) Transmission of infectious diseases during commercial air travel. The Lancet  365: 989–996. Find this article online
  19. Hayden FG, Treanor JJ, Fritz RS, Lobo M, Betts RF, et al. (1999) Use of the oral neuraminidase inhibitor oseltamivir in experimental human influenza. Journal of the American Medical Association 282: 1240–1246. Find this article online

January 18, 2007 in Governance/Management, International, Physical Science | Permalink

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Friday, April 17, 2009

Watershed Management

Cool new site: US EPA Watershed Central gives you one-stop shopping for anything related to watershed management: Watershed Central link

April 17, 2009 in Governance/Management, Science, Sustainability, US, Water Quality, Water Resources | Permalink | TrackBack (0)

Call for Entries - 4th International Water Film Festival

If you're traveling this summer, you might want to film something about water and submit your masterpiece to the 4th International Water Film Festival.  Entries are due July 31st.  For more info, visit  Drink Water for Life blog - water film festival.


April 17, 2009 in Agriculture, Biodiversity, Current Affairs, Film, Governance/Management, International, Land Use, Sustainability, Water Quality, Water Resources | Permalink | Comments (0) | TrackBack (0)

EPA to issue endangerment finding

The NY Times reported that U.S. EPA will issue a formal endangerment finding today, declaring carbon dioxide and other heat-trapping gases to be pollutants that threaten public health and welfare.  This will cause EPA to begin the process of regulating these substances from vehicles, require the technology-based New Source Performance Standards (NSPS) for stationary sources to cover greenhouse gases (GHGs), and require Prevention of Significant Deterioration (PSD) and New Source Review (NSR) permits for new and major modifications of large stationary sources to cover GHGs. 

In briefing Congress in advance of the ruling, EPA said the science supporting the endangerment finding was “compelling and overwhelming.” The ruling triggers a 60-day comment period before any proposed regulations governing emissions of greenhouse gases are published.  The endangerment finding is issued somewhat over two years after the Supreme Court in Massachusetts v. EPA ordered EPA to make a determination about whether GHGs are harmful to human health or the environment.  

By issuing the finding, EPA will force Congress to grapple with and enact global warming legislation, or face the prospect that EPA will use the Clean Air Act to regulate GHGs.  The Clean Air Act regulatory structure is far less tailored to GHGs than global warming legislation would be and is arguably far more draconian than global warming legislation proposed to date.

April 17, 2009 in Air Quality, Climate Change, Energy, Governance/Management, Physical Science, Science, Sustainability, US | Permalink | Comments (0) | TrackBack (0)

Saturday, April 11, 2009

65% see current economic crisis as opportunity for sustainability

I was browsing at Worldwatch Institute and saw these results from their poll.  By the way, I voted for reengineering the energy system:

What opportunities for sustainability may emerge in 2009
because of the current economic crisis?

The world could get a respite from surging carbon emissions.
8% (312 votes)
Significant steps will be made to reengineer the energy system in order to create jobs.
32% (1288 votes)
People will buy less stuff, and generally produce less waste.
25% (987 votes)
Opportunities will actually be hindered because bad economic times put the environment low on policymakers’ agendas.
35% (1387 votes)
Total votes: 3974

April 11, 2009 in Climate Change, Economics, Energy, Governance/Management, International, Sustainability | Permalink | TrackBack (0)

Friday, April 3, 2009

Arctic Sea Ice Melting Fast

According to a new report by Wang and Overland in Geophysical Research Letters, the arctic sea ice is melting fast enough that it will be largely gone within 30 years.  The ice is melting so fast because arctic temperatures in the last four years have risen to a level (a 9 degree Fahrenheit increase) which was not expected to occur for another 60 years.  The sea ice reflects sunlight so the planet will heat even faster as the ice melts.  So....perhaps all of those changes that we were expecting in 2010 may be here by 2040, or earlier.

Common Dreams reports:

[Wang and Overland] expect the area covered by summer sea ice to decline from about 2.8 million      square miles normally to 620,000 square miles within 30 years.Last year's summer minimum was 1.8 million square miles in September, second lowest only to 2007 which had a minimum of 1.65 million square miles...Arctic sea ice reached its winter maximum for this year at 5.8 million square miles on Feb. 28. That was 278,000 square miles below the 1979-2000 average making it the fifth lowest on record. The six lowest maximums since 1979 have all occurred in the last six years.  Common Dreams Arctic Sea Ice

April 3, 2009 in Asia, Climate Change, Governance/Management, International, North America, Physical Science, Sustainability | Permalink | Comments (0) | TrackBack (0)