Role of Nonmigratory Mottled Ducks (Anas fulvigula) as Sentinels for Avian Influenza Surveillance

Abstract

The objective of this study was to evaluate the mottled duck (Anas fulvigula), a nonmigratory dabbling duck, as a sentinel species for avian influenza virus (AIV) surveillance. A total of 235 cloacal swabs from 147 live-captured and 88 hunter-harvested mottled ducks during summer (June-August 2007) and winter (November 2007 to January 2008), respectively, were collected along the upper Texas coast. Samples were screened for AIV using real-time reverse transcription polymerase chain reaction (rRT-PCR); all rRT-PCR-positive samples were processed for virus isolation. Three samples were positive for AIV by AIV-matrix rRT-PCR. One of these samples also was positive for H5 by rRT-PCR, and a low pathogenic H5N2 AIV was isolated. Although isolation of AIVs from mottled ducks during the winter has been reported previously, to the authors' knowledge, this is the first H5 isolate from mottled ducks. Interestingly, this isolation was made during the same season that other H5N2 viruses were obtained from migratory waterfowl on the Texas coast, which suggests AIV transmission among waterfowl on the wintering grounds and the potential role of mottled ducks as a naturally occurring sentinel species for AIV surveillance.