Avian Flu Shows Minor Impact in Mongolia

A pathogenic form of the H5N1 strain of avian flu has been identified in samples taken from wild birds in Mongolia, but the effects of this strain on wild birds in the area has overall been miniscule, according to a team of researchers from the U.S. Wildlife Conservation Society (WCS, New York, NY, USA) who traveled to the area. Positive identification of H5N1 was made by the U.S. Department of Agriculture (USDA, Washington, DC, USA).

The team was responding to reports from the Mongolian Ministry of Food and Agriculture of a recent outbreak of avian influenza in Kovsgol province, near the Russian border. After traveling to the site of the outbreak with representatives of Mongolian scientific, agricultural, and health ministries, the team collected samples of hundreds of wild birds, including the whooper swan, Eurasian wigeon, and herring gull. Overall, around 6,500 apparently healthy birds of 55 species were observed. Around 100 dead birds were found at the site. This small figure suggested to the team that either the virus had little effect on the birds or that very few were actually infected with the H5N1 virus.

The team sent 774 samples to the U.S. Department of Agriculture's poultry research laboratory in Athens (GA, USA) to determine whether the virus was the H5N1 strain. As of August 19, 2005, preliminary tests from one dead whooper swan from Mongolia have shown the presence of the H5N1 strain, while results from 30 live whooper swans living at the same site tested negative for the virus. Samples collected from other live birds at the same sites were also found to be negative.

According to the WCS team, this finding suggests that while the highly pathogenic avian influenza can be carried across long distances, the waterfowl species identified in recent outbreaks appear to be victims rather than effective carriers of the disease.

WCS experts warn that to contain a potential epidemic, prevention activities must include better management practices on farms, especially those that are small and open-air farms, where domestic poultry and waterfowl are allowed to intermingle with wild birds. Officials should monitor wildlife markets where wild and domesticated species are kept in close proximity and risk exposure to a wide range of pathogens.




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