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UN agency warns of possible resurgence of H5N1

The Food and Agriculture Organization of the United Nations recommended heightened readiness and surveillance due to the possibility of a significant resurgence of highly pathogenic H5N1 avian influenza. A mutant strain of the virus is spreading throughout Asia, according to an agency press release.

“The advance appears to be associated with migratory bird movements,” according to Juan Lubroth, Food and Agriculture Organization (FAO) chief veterinary officer. “Migrations help the virus travel over long distances, so H5N1 has in the past 24 months shown up in poultry or wild birds in countries that had been virus-free for several years. Wild birds may introduce the virus, but peoples’ actions in poultry production and marketing spread it.”

Israel, the Palestinian territories, Bulgaria, Romania, Nepal and Mongolia are the areas affected by the strain, according to the press release. More recently, a variant strain of the virus surfaced in China and Vietnam. According to FAO officials, the strain could circumvent the defense mechanisms of the existing vaccine.

The H5N1 strain has invaded most of northern and central Vietnam, where the virus is endemic. “Circulation of the virus in Vietnam poses a direct threat to Cambodia, Thailand and Malaysia, as well as endangering the Korean peninsula and Japan further afield,” FAO officials said in the release.

“The general departure from the progressive decline observed between 2004 and 2008 could mean that there will be a flare-up of H5N1 this fall and winter, with people unexpectedly finding the virus in their backyard,” Lubroth said in the release. “The countries where H5N1 is still firmly entrenched — Bangladesh, China, Egypt, India, Indonesia and Vietnam — are likely to face the biggest problems, but no country can consider itself safe. Preparedness and surveillance remain essential. This is no time for complacency. No one can let their guard down with H5N1.”

For the time being, enhanced surveillance would appear to be the best course of action. Unfortunately, activity of this virus is occurring in parts of the world where surveillance is generally less than optimal. If there indeed is a mutant H5N1 virus, we know little or nothing about its infectivity or transmissibility at this point. Watchful waiting is the order of the day. We await further information with great interest.

Theodore C. Eickhoff, MD
Infectious Diseases in Children Editorial Board member

This is not entirely unexpected. It reinforces the need for continuing thorough surveillance of human disease and the need for ongoing pandemic planning by public health authorities and health care facilities around the globe. We recognize that most influenza vaccine around the world is still produced in hen's eggs, and whenever we have a large outbreak of avian influenza, there's a potential threat to egg-based production. This reminds us that there is a need to move the production of influenza vaccines away from the technology of the 1940s and 1950s into contemporary cell-based methods. Western Europe, and indeed the entire Western Hemisphere, including North and South America, are still remote from avian influenza. But given what we learned the last time, it's only a matter of time before these migratory birds and other methods of transmission, including the sale of poultry as well as chicken waste (which is used as fertilizer), are transported in commerce to other countries. We were spared that last time in the Western Hemisphere, but avian influenza could penetrate the Western Hemisphere, so we must maintain rigorous public health surveillance mechanisms.

William Schaffner, MD
President, National Foundation for Infectious Diseases

Disclosure: Dr. Schaffner reports no relevant financial disclosures.

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