Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2007
Publication Date: 9/20/2007
Citation: Douglas, K.O., Lavoie, M.L., Suarez, D.L., Afonso, C.L., Kim, L.M. 2007. Isolation and genetic characterization of avian influenza viruses and a Newcastle disease virus from wild birds in Barbados: 2003-2004. Avian Diseases. 51(3):781-787. Interpretive Summary: Avian influenza is naturally found in wild bird species like ducks and gulls. The virus normally causes no disease in these species. However, virus from these natural reservoirs of infection can spread to poultry, including chickens and turkeys. To try and better understand when and where wild birds and infected, this study looked at a number of wild bird species in Barbados for evidence of infection with avian influenza. This is the first reported study looking for avian influenza in wild birds from a Caribbean country, and provides a basis for future studies. Two avian influenza viruses were identified in blue wing teal, a duck species. Blue wing teal are known to be commonly infected with avian influenza. This study confirms that avian influenza is present in wild birds in Barbados.
Technical Abstract: Migratory waterfowl and shorebirds are regarded as the primordial reservoir of all influenza A viral subtypes and have been repeatedly implicated in avian influenza outbreaks in domestic poultry and swine. All of the 16 haemagglutinin (HA) and 9 neuraminidase (NA) influenza subtypes have been isolated from wild birds but waterfowl of the Order Anseriformes are the most commonly infected. Zoonotic transmission of an H5N1 avian influenza A virus to humans in 2003-present has generated increased public health and scientific interest in the prevalence and variability of influenza A viruses in wild birds and their potential threat to human health. Using 9-11 day old embryonated chicken egg (ECE) culture, virus isolation attempts were conducted on 168 cloacal swabs from varied resident, imported and migratory bird species in Barbados during July – October 2003 and 2004. Haemagglutination test, reverse transcription polymerase chain reaction (RT-PCR) and real time RT-PCR were used to screen all allantoic fluids for the presence of haemagglutinating agents, influenza A virus and Newcastle Disease virus (NDV) respectively. Two influenza A viruses and 1 NDV were isolated. An influenza virus isolation rate of 5.0 % (2/40) was observed in ducks (Anatidae). Data from phylogenetic analyses conducted on influenza A virus isolates support the tenet of genetic reassortment among avian influenza viruses in wild birds. This is the first report of the presence of influenza A viruses in migratory birds in the English-speaking Caribbean.