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About the Authors:
Antoinette J. Piaggio
* E-mail: [email protected]
Affiliation: National Wildlife Research Center, Wildlife Services, United States Department of Agriculture, Fort Collins, Colorado, United States of America
Susan A. Shriner
Affiliation: National Wildlife Research Center, Wildlife Services, United States Department of Agriculture, Fort Collins, Colorado, United States of America
Kaci K. VanDalen
Affiliation: National Wildlife Research Center, Wildlife Services, United States Department of Agriculture, Fort Collins, Colorado, United States of America
Alan B. Franklin
Affiliation: National Wildlife Research Center, Wildlife Services, United States Department of Agriculture, Fort Collins, Colorado, United States of America
Theodore D. Anderson
Affiliation: National Wildlife Research Center, Wildlife Services, United States Department of Agriculture, Fort Collins, Colorado, United States of America
Sergios-Orestis Kolokotronis
Affiliation: Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America and Department of Biological Sciences, Fordham University, Bronx, New York, United States of America
Introduction
Waterfowl and shorebirds are regarded as natural reservoirs for avian influenza A viruses (AIV) [1], [2]. Many species of waterfowl have the potential to shed high quantities of AIV in their feces, which can then be transmitted to other individuals when these birds congregate in large numbers in aquatic environments [1], [3], [4]. While clinical signs are generally absent in wild bird hosts infected with AIV, these viruses are of interest to agricultural operations because they can cause disease and loss of production in poultry.
Influenza subtypes are defined by the antigenicity of the hemagglutinin (HA) and neuraminidase (NA) envelope proteins [1]. Sixteen HA antigens (H1–H16) and nine NA antigens (N1–N9) have been isolated from at least 12 orders of wild birds [5]–[8]. Two virulence phenotypes have been described for AIV based on their pathogenicity in poultry: low pathogenic avian influenza viruses (LPAIV) and highly pathogenic avian influenza viruses (HPAIV) [6]. To date, only H5 and H7 subtypes have been responsible for HPAIV phenotypes in birds [6]. Since 1997 Southeast Asian strains of HPAIV H5N1 have been responsible for high mortality in domestic poultry, as well as causing severe disease in some wild birds and mammals, including humans [9]. The westward expansion of Asian strain HPAIV H5N1 brought renewed attention to the threat that AIV pose to wildlife, livestock, and human health.
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