Virginia turkeys show signs of H5 avian flu exposure

Jul 9, 2007 (CIDRAP News) – A Virginia agriculture official announced today that a turkey flock in Shenandoah County has tested positive for antibodies to a nonlethal H5 avian influenza virus, indicating possible past exposure.

Richard Wilkes, state veterinarian for the Virginia Department of Agriculture and Consumer Services (VDACS), said routine tests conducted 3 days ago, before the apparently healthy birds were scheduled to be slaughtered, were suspicious for antibodies to low-pathogenic avian flu, according to a VDACS press release.

Tests conducted over the weekend at the US Department of Agriculture's (USDA) National Veterinary Services Laboratory in Ames, Iowa, confirmed the presence of the H5 avian flu antibodies, Wilkes said in the press release.

The unidentified farm is west of Mount Jackson, according to an Associated Press (AP) report today. Shenandoah County is in northern Virginia on the West Virginia border.

"So far USDA testing has not identified the actual virus that caused the birds to produce the antibodies," he said, adding that the Ames lab hopes not only to identify the virus, but also to determine its source.

No sick birds
The turkeys did not show any signs of illness before they were tested, and the presence of avian flu antibodies does not pose a health risk to humans, Wilkes said. None of the birds entered or will enter the food chain, he added.

The 54,000-bird flock will be culled as soon as possible and composted on site, Wilkes reported. He said federal and state policies dictate eradication of H5 and H7 viruses because, even when mild, they can mutate into more dangerous forms.

The agriculture department is closely monitoring poultry operations within a 6-mile radius of the affected farm, Wilkes said.

Hobey Bauhan, president of the Virginia Poultry Federation, said a similar strain struck poultry in the Shenandoah Valley in 2002, the AP reported. According to an overview of that outbreak, published in a 2003 issue of Avian Diseases, a low-pathogenic H7N2 virus was implicated. The outbreak affected 197 farms, mostly turkey operations, and led to the culling of more than 4.7 million birds, costing the poultry industry $130 million.

Though no source was definitively established, genetic sequencing determined that the virus was nearly identical to isolates that had been circulating in live bird markets in New York and New Jersey for the previous 8 years.

Germany culls poultry
In other developments, officials in Germany culled 1,200 farm and pet birds after a pet goose tested positive for deadly H5N1 avian flu, Reuters reported today. The goose was on a farm in Thueringen, one of four German states that recently reported finding the virus in swans and other wild birds.

All farm and pet birds were culled within a 3-kilometer radius of the home where the infected pet goose was found, a Thueringen state government spokesman told Reuters. He said the goose had been allowed to wander freely and probably had contact with wild birds.

The number of infected birds in Germany has risen to 43, plus the pet goose, a spokeswoman for the Friedrich-Loeffler animal diseases institute told Reuters. So far the disease has not been found in any farm birds, she said.

Meanwhile, the Jul 5 issue of Eurosurveillance Weekly reported on a genetic analysis of the recent H5N1 findings in European birds. The analysis showed that the viruses identified recently in the Czech Republic and Germany are highly similar, but they differ from those found in the United Kingdom and Hungary.

The strains isolated from domestic birds in the Czech Republic and wild birds in Germany are more closely related to strains found in the Middle East—including Bangladesh, Pakistan, and Azerbaijan—and Russia, the Eurosurveillance report says.

The source of the infection in the Czech Republic birds is still under investigation, the report says. No wild birds in the vicinity have tested positive for the H5N1 virus.

"However, the fact that the outbreaks in domestic poultry coincided with the first reports of cases in wild birds in the EU [European Union] in 2007 is probably more than a coincidence," the report states. "It may indicate that the virus remains present intermittently in wild bird populations within some member states."

The reemergence of H5N1 in European bird populations is a concern, but it is not unexpected, the authors say. Active surveillance so far suggests that H5N1 infection in wild birds is not as widespread or intense as it was in the early spring of 2006. However, the cases are a reminder of the importance of surveillance.

"This provides an essential early warning of the presence of the virus," the report states. "If it is found in birds, it is vital that containment measures are rapidly deployed to control infection to prevent the virus from becoming established in domestic poultry."

See also:

Akey BL. Low-pathogenicity H7N2 avian flu outbreak in Virginia during 2002. Avian Dis 2003;47(3s):1099-103 [Abstract]

Eurosurveillance Weekly report on European H5N1 outbreaks

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