Avian Influenza Virus in the Aquatic Environment: Surveillance in Waterfowl Habitat on the Delmarva Peninsula
Christine Densmore1*; Diann Prosser2; Deborah Iwanowicz1; Chris Ottinger1; Luke Iwanowicz1; Larry Hindman3; Shawn McLaughlin4; Cindy Driscoll5; Matt Whitbeck6; Amanda Bessler6
1US Geological Survey, National Fish Health Research Laboratory, Leetown Science Center, Kearneysville, WV, USA; 2US Geological Survey, Patuxent Wildlife Research Center, Laurel, MD, USA; 3Maryland Department of Natural Resources, Cambridge, MD, USA; 4National Oceanic and Atmospheric Administration, Cooperative Oxford Laboratory, Oxford, MD, USA; 5Maryland Department of Natural Resources, Cooperative Oxford Laboratory, Oxford, MD, USA; 6US Fish and Wildlife Service, Chesapeake Marshlands NWR Complex, Cambridge, MD, USA
Biosurveillance for avian influenza viruses (AIV) is an important component of risk assessment for associated disease among wild bird populations, domestic birds, and humans. Avian influenza viruses may persist in aquatic environments apart from avian hosts for a substantial time. Thus, an understanding of the prevalence of AIV among wild bird populations as well as establishment of AIV in other reservoirs within the habitat is critical to the anticipation of potential consequences of the virus' overall presence in the Delmarva Peninsula and elsewhere. The objectives of this pilot study included determining the feasibility and practicality of isolation of AIV from potential environmental reservoirs, including water, pond sediment, and sentinel caged oysters in waterfowl habitat; and comparing findings for detection of AIV from wild aquatic bird populations to the detection of AIV from these environmental reservoirs. Approximately 1000 samples consisting of avian oropharyngeal/cloacal swabs from dabbling duck species, submerged or pond-edge sediment samples collected from high-density waterfowl habitat, or sentinel oyster tissue homogenates were collected in 2013–2014. Additionally, eight 10-L water samples were collected from high-density waterfowl habitat and filter-concentrated for analysis. Extracted RNA from specimens was converted to cDNA and screened for the presence of the avian influenza virus matrix gene via quantitative reverse transcriptase PCR (qRT PCR). Presumptive positive samples underwent repeat testing with qRT-PCR for confirmation. Avian influenza virus matrix gene was detected in approximately 14% of sediment samples, a higher rate as compared to bird-source swabs. One oyster tissue homogenate of the approximately 300 tissue samples collected also tested positive. No avian influenza genetic material was recovered from any of the 8 water samples tested. Results suggest that sampling of environmental reservoirs, particularly pond sediment, from high waterfowl density habitat may be useful in biosurveillance for AIV in this region.
* Presenting author