Zoonotics’s Weblog

             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.