Your Family Physician

When President Obama remarked in his April 29 press conference that closing the US-Mexico border to prevent the spread of swine flu was akin to closing the barn door after the horses had bolted, he was reflecting the opinion of many public health experts.

"Given the widespread presence of the virus across many countries containment is probably not feasible, and efforts need to focus increasingly on mitigation," writes Richard Coker, MBBS, MSc, from the London School of Hygiene and Tropical Medicine's Faculty of Tropical Medicine, at the University of Mahidol, Bankgok, Thailand, in an editorial published online April 30 in the BMJ.

As of April 30 at 11:00 am ET, the CDC listed a total of 141 confirmed cases of the swine influenza A H1N1 strain, with cases in Arizona (4), California (13), Colorado (2), Delaware (4), Illinois (3), Indiana (3) Kansas (2), Kentucky (1), Massachusetts (2), Michigan (2), Minnesota (1), Nebraska (1), Nevada (1), New Jersey (5), New York (50), Ohio (1), South Carolina (16), Texas (28), and Virginia (2).There was also 1 reported death, a child from Mexico visiting relatives in Texas.

The World Health Organization (WHO) said that as of 6:00 am GMT, May 1, a total of 331 cases had been reported from 11 countries, in addition to the United States and Mexico, including Austria, Canada, Germany, Israel, the Netherlands, New Zealand, Spain, Switzerland, and the United Kingdom. The WHO has raised its level of alert to 5 on a scale of 6, indicating that a global pandemic is imminent.

Plans Are One Thing, Implementation Another

Although most industrialized and many developing nations have learned the lessons of the severe acute respiratory distress syndrome (SARS) and avian influenza H5N1 strain epidemics, and have both pandemic contingency plans and stockpiles of antiviral medications in place, developing countries may still be unequipped to contain or treat outbreaks, according to the BMJ editorial and a similar one published online April 28 in The Lancet.

"Analyses of national strategic plans around the world show that although most countries now have plans, many countries, especially developing countries, will struggle to put them into operation," Dr. Coker writes. "This is because they have limited health system resources to call on in the event of a pandemic; they have not stockpiled antiviral drugs in anything like the numbers needed for mitigation purposes (and if they had, they might struggle to mobilize them effectively); and they are unlikely to receive an effective vaccine early (if at all), once it is produced in large amounts."

That concern is echoed by the editors of The Lancet, who write in an editorial that "of particular concern is the ability of low-income and middle-income countries to detect and mitigate the effects of this new virus on their populations. History has shown that developing countries are disproportionately affected by an influenza pandemic."

Unreported Cases

Dr. Coker notes that nearly all of the confirmed cases of influenza A H1N1 — the term now used by the CDC and the WHO to avoid casting aspersions on swine and the pork products industry — are in industrialized countries with good surveillance systems. It raises the question, he says, of whether there aren't more, unreported cases lurking in the background, unreported to public health systems in developing countries.

And it isn't just in less affluent places: New York City Mayor Michael Bloomberg said at a press conference on April 30 that in addition to the laboratory-confirmed cases, there were many more likely cases among students at the St. Francis Preparatory School, where the outbreak first surfaced in the city.

"If we went and tested all of the students at St. Francis, we'd have hundreds of cases. We know what they've got and we'd just be tying up resources," Mr. Bloomberg said.

According to Dr. Coker, developing countries have nowhere near the amount of the antiviral agents oseltamavir (Tamiflu, Roche) or zanamavir (Relenza, GlaxoSmithKline) needed for mitigation efforts, and even if they did, would be hard-pressed to distribute them.

"[A]though many developed countries, including most of Western Europe and the US, have sizeable stockpiles of antiviral drugs, most low and middle income countries have low or non-existent stocks," he writes. "The rapid response stockpile of three million treatments of oseltamivir, and the two million treatments stockpiled by WHO as regional stockpiles for use in developing countries, are intended principally for rapid containment, and they will not go far to support mitigation efforts."

In addition, he cites several studies suggesting that should an effective vaccine become available, developing countries would be unlikely to get it in time or indeed at all.

In an interview with Medscape Infectious Diseases, Georges C. Benjamin, MD, FACP, FACEP (E), executive director of the American Public Health Association, said that public health authorities around the world will need to cooperate to ensure that developing nations have the resources they need in the event of a global pandemic.

"We need to be looking at prepositioning medicine and supplies on a global basis, to be able to aid those countries," he said. "We know what happens when they have drought, we know what happens when they have severe infectious diseases, and now we have to make sure that they have access to clean water, that they have surveillance systems in place for early detection when disease hit those communities, and understand that they may not have clean water available or soap for handwashing in small villages.

"Those are always real challenges," Dr. Benjamin said. "We need to figure out how to empower the leaders in those countries to get the message out, and we ought to be doing that now."

Swine + Avian Influenza = ?

Another issue that Dr. Coker and others have raised is that a new strain of flu could arise from the potential intermingling of swine and avian flu strains.

"Immunity to H1N1 will not offer protection to H5N1 if that also becomes readily transmissible between humans," Dr. Coker writes. "As H1N1 spreads to areas where H5N1 is endemic, do we face an even greater challenge — that of reassortment of these two viruses and the threat of another pandemic?"

In an interview with Medscape Infectious Diseases earlier this week, Neal A. Halsey, MD, professor in the Department of International Health, Bloomberg School of Public Health, Johns Hopkins University in Baltimore, Maryland, notes that swine "are a great mixing bowl, because they are susceptible not only to the swine flu, but also influenza from birds and influenza from humans."

An individual pig can contain several different viruses simultaneously, Dr. Halsey said, and these viruses can mix into new and potentially highly infectious forms.

Dr. Benjamin added that other conditions in developing countries may conspire to exacerbate pandemic influenza when it arrives.

"Two things we have not yet seen: (1) we know that even a mild pandemic that results in people getting severely dehydrated, especially in children, with fever and not enough water to drink can be life-threatening, and (2) is the effect on a population which is heavily impacted by HIV/AIDS or has another automimmue problem. We've not seen that yet, but it's only a matter of time," he said.

Asked whether, given the global economic crisis, public health authorities would be able to coordinate funds and efforts, Dr. Benjamin had a stark and simple answer: "We don't have a choice."

Source : http://www.medscape.com/viewarticle/702227