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Title: Pathogenesis and transmission of H7 and H5 highly pathogenic avian influenza viruses in mallards including the recent intercontinental H5 viruses (H5N8 and H5N2)

Author
item Pantin Jackwood, Mary
item Spackman, Erica
item Kapczynski, Darrell
item Suarez, David
item COSTA-HURTADO, MAR - Orise Fellow
item DEJESUS, ERIC - Orise Fellow
item Shepherd, Eric
item Smith, Diane
item Swayne, David

Submitted to: International Symposium on Avian Influenza
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2015
Publication Date: 4/12/2015
Citation: Pantin Jackwood, M.J., Spackman, E., Kapczynski, D.R., Suarez, D.L., Costa-Hurtado, M., Dejesus, E., Shepherd, E.M., Smith, D.M., Swayne, D.E. 2015. Pathogenesis and transmission of H7 and H5 highly pathogenic avian influenza viruses in mallards including the recent intercontinental H5 viruses (H5N8 and H5N2) [abstract]. 9th International Symposium on Avian Influenza, Athens, Georgia. p. 37.

Interpretive Summary:

Technical Abstract: Highly pathogenic avian influenza viruses (HPAIV’s) remain a threat to poultry worldwide. Avian influenza viruses, including HPAIV, are usually non-pathogenic for ducks and other wild aquatic birds, with the exception of Asian lineage H5N1, and recently H5N8, HPAIVs, which can cause moderate to severe disease in ducks. With the continuous occurrence of HPAI outbreaks in poultry it’s important to address the role of wild birds in the transmission and spread of HPAIV’s. We conducted a study in which we inoculated 2-weeks-old mallard ducks (Anas platyrhynchos) intranasally with 10^6 embryo infective dose 50 (EID50) of one of eleven strains of HPAIV subtypes H5 or H7, including isolates from different years and countries. Pathogenesis (clinical signs, lesions), presence of the viruses in tissues, duration and titer of virus shedding for each virus, transmission to contact birds, and seroconversion to all viruses was evaluated. Although no clinical signs or mortality were observed, ducks became infected with most of the viruses given and transmitted the viruses to contact ducks. Viral shedding occurred by both the oropharyngeal and cloacal routes indicating previous adaptation to poultry. Many of the viruses were still being detected 14 days after inoculation. Viruses that had circulated for longer periods of time in poultry, like the Mexican H5N2 HPAIV, were less infectious for ducks. These results raise concerns about possible spreading of HPAIV’s by infected wild ducks.