Oregon reports H5N8 virus in backyard poultry
An H5N8 influenza virus has been detected in a backyard poultry flock in southwestern Oregon, the Oregon Department of Agriculture (ODA) reported today, just 3 days after H5N8 and H5N2 viruses were found in wild birds in neighboring Washington.
The virus was found in guinea fowl and chickens from a backyard flock of about 100 birds in the Douglas County town of Winston, the ODA reported. The flock has access to the outdoors, and migratory birds frequent a pond and marsh on the property, the statement said.
The agency said the virus was found quickly because of increased awareness sparked by the avian flu detections in Washington. "This H5N8 virus is the same virus that was found in a Washington captive gyrfalcon," the statement said.
"The virus has not been found in commercial poultry anywhere in the US," the ODA said. "Surveillance for avian influenza is ongoing in commercial poultry operations, live bird markets, and in migratory wild bird populations."
"Steps are being taken to contain the disease and we have not diagnosed avian influenza elsewhere in Oregon's domestic poultry population, but the presence of the virus in migratory waterfowl poses a potential risk to our backyard poultry," said ODA State Veterinarian Brad LeaMaster, DVM, PhD. He didn't specify what the control steps are.
He urged poultry owners to prevent contact between their birds and wild birds, monitor their flocks, and report any sick birds.
In Washington, an H5N8 virus was found in a captive gyrfalcon that had been fed hunter-killed birds, federal and state agencies reported on Dec 16. In addition, an H5N2 virus was found in a wild pintail duck after a waterfowl die-off at Wiser Lake. Both detections were in Whatcom County, which is just across the border from the area of an ongoing H5N2 outbreak on poultry farms in British Columbia.
The US Department of Agriculture said the Washington H5N2 virus is similar to the one circulating in British Columbia. In addition, a bulletin from the US Geological Survey's (USGS's) National Wildlife Health Center this week said the H5N8 and H5N2 isolates both may be related to a highly pathogenic H5N8 virus "previously known to have circulated during 2014 among wild birds and poultry . . . in Asia and Western Europe."
Several H5N8 outbreaks have been reported since early November on poultry farms in Germany, the Netherlands, the United Kingdom, and Italy (see item below). Earlier in the year, South Korea was hit by widespread H5N8 outbreaks in poultry.
No H5N8 or H5N2 infections have ever been reported in humans, according to federal officials.
Dec 19 ODA statement
Dec 16 USGS bulletin
Related Dec 16 CIDRAP News story
Report notes similarities between H5N8 and earlier H5N1 in Europe
The introduction of H5N8 avian flu in Europe in recent weeks is in some ways comparable to the introduction of H5N1 to the continent almost a decade ago, although there are still many unknowns regarding how H5N8 arrived, a report yesterday in Eurosurveillance noted.
From Nov 5 through Dec 16, officials have confirmed nine H5N8 poultry outbreaks in Germany, Italy, the Netherlands, and the United Kingdom, as well as in wild birds in Germany and the Netherlands.
The affected area in Germany is similar to that affected in 2005 by H5N1 as that strain spread across Europe after first being detected in 2005, the report said. Britain and Italy were also affected in 2006 by H5N1 but in different regions than with H5N8, while the Netherlands was not affected at all by H5N1.
The spread of H5N1 from East Asia to Europe about 9 years ago may have occurred via a activities related to poultry production, illegal poultry trade, spillover infections to wild birds, and migratory-bird dispersal, "but no consistent route of infection into poultry holdings within Europe has been identified," the authors wrote. Two-way transmission of H5N8 might likewise occur, they say, and note that recent genetic analyses have shown high similarity between European H5N8 and H5N8 viruses from wild birds in Japan.
The authors conclude, "These similarities may point to common routes of introduction into Europe, although these are not fully understood and the exact sources of infection of the affected indoor poultry holdings have not been identified yet."
Similarly, a report earlier this week from the European Food Safety Authority (EFSA) concluded that the path of H5N8 into Europe has not yet been fully elucidated.
Dec 18 Eurosurveillance report
Dec 15 EFSA report