Avian influenza continues spreading, but global response improves

Europe could join Asia and Africa as a continent where highly pathogenic H5N1 avian influenza is endemic, warns the United Nations Food and Agriculture Organization.

Earlier this year, though, the FAO and World Organization for Animal Health (OIE) stated that global response to H5N1 avian influenza has improved and that countries reported fewer outbreaks in early 2007 than in early 2006—when the virus reached many European countries in wild birds.

The recent FAO warning followed Germany's detection of H5N1 avian influenza in young domestic ducks that did not have clinical signs of infection.

"It seems that a new chapter in the evolution of avian influenza may be unfolding silently in the heart of Europe," said Dr. Joseph Domenech, FAO chief veterinary officer. "If it turns out to be true that the H5N1 virus can persist in apparently healthy domestic duck and geese populations, then countries need to urgently reinforce their monitoring and surveillance schemes in all regions with significant duck and geese production for the presence of H5N1."

The FAO expressed particular concerns about countries bordering the Black Sea. The region has a substantial population of domestic ducks and geese, as well as chickens, and serves as a wintering area for migratory birds. The region also favors traditional open poultry systems with poor separation between domestic and wild birds. All countries bordering the Black Sea have experienced outbreaks of H5N1 avian influenza.

Dr. Domenech stated earlier this year that the overall response to H5N1 avian influenza in poultry has improved substantially during the past three years. Reports of human cases occur only sporadically, apart from a few countries. Nevertheless, the virus continues to spread to new countries.

"Even if bird flu has disappeared from our TV screens, it doesn't mean that the risk is over," Dr. Domenech said.

The OIE stated earlier in the year that most countries have dealt successfully with outbreaks of H5N1 avian influenza. Dr. Bernard Vallat, director general, said countries reported fewer deaths of wild birds from the virus in early 2007.

"Poultry flocks still continue to be infected in some countries," Dr. Vallat said. "That shows the international community needs to keep up its high level of prevention and control measures of the disease in animals."

The OIE stated that the disease remains endemic in at least three countries—Egypt, Indonesia, and Nigeria. The virus spread to Bangladesh, Ghana, Saudi Arabia, and Togo for the first time between February and June of this year. As of Nov. 12, the World Health Organization reported a total of 335 cases of human infection since 2003, with 206 fatalities.

On the subject of vaccination for avian influenza, the Council for Agricultural Science and Technology recently released a special publication and commentary.

The publication, "Avian influenza vaccines: Focusing on H5N1 high pathogenicity avian influenza," covers the science of vaccines for avian influenza, art of controlling avian influenza, and analysis of previous vaccine campaigns.

The full text of CAST Special Publication No. 26 is available by visiting www.cast-science.org or calling (515) 292-2125. A hard copy costs $18 plus shipping, and an electronic download costs $10. The commentary, an excerpt from the publication, is available free on the Web site.