US authorities today reported finding wild birds in Washington state infected with two different highly pathogenic avian influenza (HPAI) viruses, H5N2 and H5N8, raising questions about possible connections with recent H5N2 outbreaks across the border in Canada and with an Asian H5N8 strain that is now hitting European poultry farms.
In reports to the World Organization for Animal Health (OIE), the US Department of Agriculture (USDA) said H5N2 was found in a wild pintail duck, while H5N8 was found in a captive wild gyrfalcon that was fed on hunter-killed birds. Both birds were in Whatcom County, Washington, which borders the Abbotsford area of British Columbia, the site of recent H5N2 outbreaks in poultry.
Also today, Italy became the fourth European country in the past few weeks to report an H5N8 outbreak in poultry, with an outbreak on a turkey farm, and Germany reported a second poultry H5N8 outbreak at a site distant from its first H5N8 event.
Increased surveillance prompted finds
Both US viruses were detected because of increased surveillance prompted by the Canadian H5N2 outbreaks. The USDA said neither virus has been found in any poultry in the United States.
In a "stakeholder announcement," the USDA said, "There is no immediate public health concern with either of these avian influenza viruses. Both H5N2 and H5N8 viruses have been found in other parts of the world and have not caused any human infection to date."
In its OIE reports, the agency said, "Preliminary analysis suggests this H5N2 is similar to the HPAI identified in the current Canadian outbreak." The report was filed by John Clifford, DVM, deputy director of the Animal and Plant Health Inspection Service (APHIS). The agency filed separate reports on the two detections, but with identical epidemiologic comments.
The report does not comment on whether the H5N8 virus is related to the H5N8 currently circulating in Europe. It says the hemagglutinin component (H5) of the H5N2 virus is related to a virus isolated from a bean goose in Korea this year, while the neuraminidase (N2) component of the H5N2 isolate is similar to that from a virus found in a US green-winged teal in 2007.
The report goes on to say, "Preliminary data suggests that these virus strains (H5N2 and H5N8) may be related with the H5N8 strain potentially representing the progenitor; however further analysis is needed."
The USDA and Washington authorities are working on additional surveillance and testing of birds in northwestern Washington, the agency said. It called on all bird owners, both commercial and noncommercial, to keep their birds separated from wild birds and to report illnesses and unusual deaths to state veterinary authorities or the USDA.
Turkey outbreak in Italy
Italian veterinary authorities, in reporting their H5N8 outbreak to the OIE, said the virus killed 1,219 of 31,985 turkeys on a farm near Venice in northeastern Italy's Veneto province.
The report said culling of the surviving turkeys to control the outbreak would begin today and that other control measures would be applied in a restriction zone around the farm. Officials also said they are sequencing the virus to determine its genotype.
Italy follows Germany, the Netherlands, and the United Kingdom in reporting recent outbreaks of H5N8 in poultry. Germany was the first, with a report of the virus on a turkey farm on Nov 4, and outbreaks were reported on chicken and duck farms in the Netherlands and the UK shortly afterward. At least four farms in the Netherlands have been struck by the virus.
The latest outbreak in Germany involves a turkey farm in the northwestern state of Lower Saxony, according to a Reuters report today. The story gave no information on the number of turkeys affected or on response efforts.
Germany's initial outbreak was on a turkey farm in Mecklenburg-Vorpommern, a northeastern state. The virus also was later found in a wild bird.
The European outbreaks follow a series of widespread outbreaks in South Korea early this year. Authorities suspect that wild birds carried H5N8 from East Asia to Europe. No human H5N8 infections have been reported as yet.
In late November the OIE and the United Nations Food and Agriculture Organization warned that H5N8 represented a serious threat to the poultry industry, especially in less-wealthy European countries.
H5 outbreak in Japan
In other developments, Japan's agriculture ministry reported today that a farm in the country's southwestern prefecture of Miyazaki was hit by a highly pathogenic H5 avian flu virus, according to a separate Reuters story. The story did not specify the virus's full subtype.
Three chickens tested positive for the virus, prompting destruction of all 4,000 chickens on the farm, an official told Reuters. The story said Miyazaki is Japan's top producer of broiler chickens.
Dec 16 US report to OIE on H5N8 in gyrfalcon
Dec 17 US report to OIE on H5N2 in duck
Dec 16 USDA statement to stakeholders
Dec 11 CIDRAP News item on H5N2 outbreaks in British Columbia
Dec 16 Italian report to the OIE
Dec 16 Reuters story on German outbreak
Dec 16 Reuters story on H5 outbreak in Japan
Nov 24 CIDRAP News story about FAO, OIE warning