Bird flu moves towards Europe
Migratory birds may have caused outbreaks in Russia and Kazakhstan.
The H5NI avian influenza virus has broken out in poultry flocks in Russia and in Kazakhstan, where a suspected human case is also being investigated.
The outbreak hints that the disease is moving towards Europe. Past outbreaks have centred on southeast Asia and, more recently, parts of China. The new incidents risk opening a Eurasian front for the disease, increasing the animal reservoir that could spark a pandemic.
"If we are seeing an expansion in range, that is something we should be concerned about," says Ian Brown, head of avian virology at the UK Veterinary Laboratories Agency in Weybridge, Surrey.
UK Veterinary Laboratories Agency
Over the past three months, more than 6,000 birds have died at Qinghai Lake in China, in the first major outbreak of H5N1 in migratory birds1. This has raised fears that birds might spread the virus worldwide, with eyes in particular on those that will fly from their breeding grounds in Qinghai to destinations across southeast Asia and India later this summer.
Suspicions of avian flu in Russia were first raised in mid-July in Suzdalka, a village in the Novosibirsk region. But officials squashed these fears. On 22 July, Alexander Shestopalov, a virologist with the state scientific centre for virology and biotechnology (Vector), told the Russian news agency Interfax that the virus was a low pathogenic strain called H5N2. "This virus is considerably less pathogenic for poultry than H5N1, which is found in Southeast Asia, and is absolutely harmless to humans," he said.
Russia's formal notification to the World Organization for Animal Health (OIE) on 24 July, however, indicated that they had not yet characterized the virus, and knew only that it was an H5 type.
The report also said that preliminary analysis showed that the disease started in a flock that was in contact with infected wild birds. It then spread to eight nearby villages, killing 350 geese, ducks, turkeys and chickens.
On 29 July, the Russian government announced that the birds had H5N1.
A few days later, a poultry worker from the village of Golubovka in Kazakhstan was admitted to hospital with the symptoms of bird flu. And the government confirmed that H5N1 was the cause of an outbreak that had killed 600 geese in that village, although the test results have not yet been formally notified to OIE. Golubovka has been quarantined.
The World Health Organization has called for samples in Russia and Kazakhstan to be tested at its laboratories.
They hope to sequence the virus and compare it to viruses from Qinghai, as well as those circulating in Southeast Asia. This should help to reveal if and how the disease is changing and spreading.
Simba Chan, an expert on cranes at the Wild Bird Society of Japan in Tokyo, says it is unlikely that the disease has come to Russia from China, as birds do not usually fly in that direction at this time of year.
Brown suggests instead that the new cases might have spread from undeclared poultry outbreaks in nearby China.
But Juan Lubroth, head of infectious diseases for the Food and Agriculture Organization (FAO), says there is still cause for concern over migratory birds. The best thing to do, he says, would be to set up surveillance areas to randomly test wild bird populations. The FAO would need US$20-30 million for such a study, he says.
- Chen H., et al. Nature, 436. 191 - 192 ( 2005).