Using RRT-PCR analysis and virus isolation to determine the prevalence of avian influenza virus infections in ducks at Minto Flats State Game Refuge, Alaska, during August 2005

摘要: This study describes surveillance for avian influenza viruses (AIV) in the Minto Flats State Game Refuge, high-density waterfowl breeding grounds Alaska. Five hundred paired cloacal samples from dabbling ducks (Northern Pintail, Mallard, Green Wing Teal, and Widgeon) were placed into ethanol viral transport medium (VTM). Additional ethanol-preserved taken. Of samples, 25.6% AIV RNA-positive by real-time RT-PCR. The hemagglutinin (HA) neuraminidase (NA) subtypes determined 38 of first-passage isolates, four isolates could not be definitively subtyped. A virus HA–NA combinations identified: H3N6, H3N8, H4N6, H8N4, H12N5. Differences prevalence infections sex age classes Northern Pintail Mallard detected, but significance these differences is undefined. In 500 molecular screening detected positive birds at a higher rate than isolation (χ2 = 8.35, p 0.0035, df 1); however, 20 recovered PCR-negative ducks. Further research warranted to compare two protocols’ potential estimating true wild birds. Our success during 2005 indicates will valuable site longitudinal project designed gain further insight natural history, evolution, ecology