Jul 25, 2005 (CIDRAP News) – A Russian official has identified the avian influenza virus that has been killing poultry in Siberia as H5N2, a strain that is not dangerous to humans.
But another Russian official reported to the World Organization for Animal Health (OIE) yesterday that the virus had not yet been fully identified. The poultry outbreaks in the Novosibirsk region of southwestern Siberia were first reported last week.
Alexander Shestopalov, an official at the State Scientific Center for Virology and Biotechnology, identified the virus as H5N2, according to a Jul 22 report by Interfax, a Russian news agency.
"This virus is considerably less pathogenic for poultry than H5N1, which is found in Southeast Asia, and is absolutely harmless to humans," Shestopalov was quoted as saying.
But in a report to the OIE yesterday, Dr. Evgueny A. Nepoklonov, head of the Main Veterinary Department at the Ministry of Agriculture and Food in Moscow, said the N, or neuraminidase, number of the virus had not yet been determined. He confirmed that the virus had been "preliminarily" identified as an H5.
Nepoklonov's report, published on the OIE Web site, said outbreaks of avian flu were reported in nine villages in the Novosibirsk region.
He didn't mention how many birds had died, but said the mortality rate was low, from 1% to 2.6%. He told the OIE last week that more than 350 birds had died.
"An epidemiological analysis has shown that the disease started in a flock in contact with wild waterfowl at open water reservoirs," Nepoklonov's report says. "This is proposed as the primary source of the virus. In addition, there is evidence of the disease in wild birds." He also said no outbreaks had occurred at commercial poultry farms.
Shestopalov said the virus came from the Mediterranean region and probably was brought to Novosibirsk by migrating birds, according to the Interfax report.
H5N2 viruses have not been known as harmful to humans. Mexico had a series of outbreaks of highly pathogenic H5N2 in poultry from 1995 to 2003 without any human cases. A small outbreak of the virus occurred at a farm near San Antonio, Tex., in February 2004, with no human cases.
More than 100 people have been infected with H5N1 viruses and more than 50 have died in Southeast Asia since late 2003.
CIDRAP overview "Avian influenza: Agricultural and wildlife considerations"