This week a group of international scientists will resume testing for the H5N1 strain of avian influenza while thousands of migratory birds arrive in Mongolia for the summer months. Previous outbreaks in Mongolia have differed from those in other areas, presenting new information, as well as causes for concern.

Since outbreaks of the H5N1 strain of Avian Influenza were discovered in northern Mongolia in 2005, scientists now have different concerns about the large numbers of migratory birds arriving for the summer months

Mongolia has a relatively small number of poultry farms, 13 of which are located in the Ulaanbaatar area. In contrast to other nations, such as China where poultry farms have suffered bird flu outbreaks, Mongolian cases of H5N1 have occurred primarily in wild bird populations.

In August 2005, an international research team including the National Academy of Sciences, the Mongolian Institute of Veterinary Medicine, the State Central Veterinary Laboratory, the Wildlife Conservation Society (WCS), Ministry of Food and Agriculture Veterinary Department, and the Ministry of Health's Center of Communicable Diseases uncovered more than 100 dead birds at Erkhel Lake in Huvsgul province. The presence of the H5N1 virus in these birds was verified by the United States Department of Agriculture (USDA).

While more than 55 healthy bird species were observed in the same region, 27 species were again tested in early 2006. Some of the highest risk species include the ruddy shelduck, herring gull, black-headed gull, bar-headed goose, whooper swan, and Eurasian wigeon. However, testing of these species in 2005 showed very low infection rates. The strain of H5N1 that was found in bar-headed geese in Mongolia has also been identified in countries as far away as Egypt and Nigeria.

In May 2006, while the Central Veterinary Laboratory was monitoring migratory bird populations, another case of H5N1 was found in a wild whooper swan.

B. Batzorig of the Central Veterinary Hospital of the Ministry of Agriculture said that for 2006, the highest risk area has been Bulgan province; however it could only truly be determined by further observation and testing.

“If we find more cases, we will send the birds to Japan for final testing,” he commented. “Some of the high risk bird species will not return until September or October.”

While poultry farms often cull birds that are, or could be infected, scientists state that doing so with wild birds could actually create a larger potential for spreading the disease.

The WCS and United Nation's Food and Agriculture Organization (FAO) stated that, “Control of a wildlife disease through culling is likely only to be successful for diseases with low transmission rates that occur in one species and where the outbreak is contained to a small area. None of these conditions are met with H5N1: a) avian influenza is highly infectious, b) multiple species are being infected, and c) the disease is spread across much of Central and Southeast Asia.”

This week, scientists from the United States Geological Survey, WCS and the FAO will return to Mongolia for continued studies.

In eastern Mongolia the group will attempt to put tracking collars on high risk species in order to attempt to monitor migration patterns. Testing for H5N1 will also resume in previous study areas located in central and western Mongolia.