Avian Flu Scan for Jan 15, 2015

H5N2 in Oregon mallard
;
H5N8 outbreaks in Taiwan
;
H10 in Chinese birds

H5N2 found in wild Oregon mallard

In the latest detection of avian flu in wild and domestic birds in Western states, Oregon officials have confirmed the H5N2 strain in a hunter-killed mallard near Eugene, the Oregon Department of Fish and Wildlife (ODFW) said in a news release yesterday.

The female duck was sampled Dec 20 as part of routine ODFW surveillance. Results of confirmatory testing at the National Veterinary Services Laboratory in Ames, Iowa, were relayed to the ODFW on Jan 13. The mallard, which was shot at the Fern Ridge Wildlife Area, showed no signs of sickness.

The release also said there have been no recent reports of waterfowl die-offs in North America. The last one appears to have been in December. On Dec 17, the US Department of Agriculture (USDA) confirmed that H5N2 was found in northern pintail ducks after a die-off at Wiser Lake in northwestern Washington.

H5N2 has also affected several backyard poultry flocks in Washington in recent weeks and a number of commercial farms across the border in British Columbia since early December.

Another avian flu strain—H5N8—has been confirmed in recent weeks in wild birds in Utah and California, a captive gyrfalcon in Washington, and a backyard flock in southwestern Oregon. That strain was also responsible for a series of outbreaks in Europe since November and in more recent ones in South Korea and Taiwan (see item below).
Jan 14 ODFW news release
Dec 17 USDA press release on avian flu in pintails, gyrfalcon

 

Taiwan reports 4 more H5N8 outbreaks

Taiwan agriculture officials have confirmed 4 new H5N8 avian flu outbreaks on geese farms, bringing to 10 the number of such outbreaks in the past 5 days, according to a report posted today by the World Organization for Animal Health (OIE).

Two of the outbreaks are in Chiayi County, and two are in Yunlin County in the western part of Taiwan. Four of the previous outbreaks have been in Chiayi County, with one each in Yunlin and Pingtung counties, the latter being in the south.

The new outbreaks have affected farms ranging in size from 1,400 to 10,000 geese. From 4 to 3,180 birds have contracted H5N8, with all affected birds dying. The report said plans call for destroying all the birds on the affected farms to prevent disease spread.

All told, 3,298 of 21,600 geese have been infected.
Jan 15 OIE report

 

Study: H10 evolution in China highlights threat to public health

Twelve years of surveillance of H10 avian flu viruses in poultry and migratory birds in southern China—tracing the origins of the H10N8 and H10N6 strains—demonstrate the severe threat to public health posed by the viruses as they reassort in the fertile influenza ecosystem of China, according to findings of a study yesterday in the Journal of Virology.

The researchers, from several Chinese institutions as well as St. Jude Children's Research Hospital in Memphis, Tenn., carried out systematic surveillance at live-poultry markets (LPMs) and sentinel duck farms in six provinces of southern China as well as in uninhabited areas of Poyang Lake and at farms adjacent to the lake from 2002 to 2014.

They say H10 viruses that began appearing at LPMs in Jiangxi in August 2013 originated from over-wintering migratory ducks sharing the Poyang Lake area with domestic ducks, with shared viruses then transferring to LPMs, where they further reassorted with enzootic avian flu strains.

The authors state that they have isolated 124 H10N8 and H10N6 strains from local LPMs. Phylogenetic analysis has shown that H10N8 in chickens was generated through multiple reassortments between H10 and N8 viruses from domestic ducks and enzootic H9N2 viruses in chickens.

H10N8 has caused at least three human cases in recent months, two fatal.

The more recently seen H10N6 variant may have stemmed from the reassortment of the continually present H10 viruses at LPMs with H5N6 viruses, they add. No human cases have been associated with this strain.

The influenza ecosystem of China, explain the authors, is unique in its huge population of aquatic birds and terrestrial poultry and in the multiple subtypes of flu viruses existent in them, the combination of industrial and mixed-animal backyard farming, and the widespread system of LPMs.

They conclude, "All these factors make China a unique influenza epicentre for generating novel viruses with pandemic potential," and that to reduce the emergence of novel viruses and control current enzootic influenza viruses and the potential emergence of pandemic flu in China, "Revolutionary changes to the entire structure of poultry farming practices, LPMs, and the poultry distribution system are needed."
Jan 14 J Virol study abstract

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