28.07.2011

In recent years, the H5N1 subtype of avian influenza virus (AIV) has become an important zoonotic pathogen.
The surveillance of AIV in its natural host, the waterfowl, is crucial to monitoring and controlling the disease in poultry and other species. In a new study published recently in the scientific journal Avian diseases, the researchers report the isolation of H5 AIV from cloacal swabs of waterfowl captured in Minnesota and South Dakota. A total of 7260 cloacal samples from waterfowl were screened using matrix gene–directed, real-time reverse transcription-(rRT-PCR) and H5-specific rRT-PCR and found 148 samples to be positive for the H5 subtype. On inoculation of 71 of these samples in embryonated chicken eggs, 25 samples yielded H5 AIV. Eight samples were found to be H5N2, while 15 samples had a mixture of H5N1 and H5N2, one sample had a mixture of H5N1 and H1N1 and the other one had H5N8 and H4N8. Molecular pathotyping confirmed the isolated H5 subtypes to be low pathogenicity avian influenza (Av Dis 55:259-262, 2011).