Russia has identified its first case of bird flu, strains of which can spread to people and can be fatal, the Emergencies Ministry said on Thursday, but the country’s chief veterinarian could not confirm the news.

Viktor Beltsov, a spokesman for the Emergencies Ministry, said bird flu had been detected in poultry in a village in Siberia’s Novosibirsk region. Numerous birds have died…and an investigation showed the presence of the AH5-type bird flu virus,” Beltsov said.

But Sergei Dankvert, chief animal and plant safety officer, said that the death of the birds could have been caused by other factors.

“We cannot say now if something out of the ordinary has occurred. The reason behind the accident could be bad water, feed poisoning, Newcastle disease or bird flu. More investigation is needed,” Dankvert said.

Russia does not produce enough poultry for domestic needs and imports over a million tonnes of poultry meat annually, mainly from the United States, the European Union and Brazil.

Beltsov was not able to give any further details on the AH5 virus. The H5N1 strain of avian influenza has killed at least 50 people in Asia since 2003.

Indonesia confirmed on Wednesday its first deaths from bird flu, saying tests on a father and his two young daughters who died recently showed they had contracted the virus.

The bird flu virus is split into strains such as H5 and H7. Both of these, for example, have the potential to be high or low pathogenic.

Of the H5 strain, there are potentially nine different subtypes such as H5N1, H5N2 and H5N3.

The deadly strain of the virus that has struck Asia is the high pathogenic H5N1 type that can be transmitted to humans.

Other sub-types are considered less dangerous.