[Source: PLoS ONE, full text: (LINK). Abstract, edited.]
Avian Influenza Virus Surveillance in Wild Birds in Georgia: 2009–2011
Nicola S. Lewis, Zurab Javakhishvili, Colin A. Russell, Ann Machablishvili, Pascal Lexmond, Josanne H. Verhagen, Oanh Vuong, Tinatin Onashvili, Marina Donduashvili, Derek J. Smith, Ron A. M. Fouchier
The Caucasus, at the border of Europe and Asia, is important for migration and over-wintering of wild waterbirds. Three flyways, the Central Asian, East Africa-West Asia, and Mediterranean/Black Sea flyways, converge in the Caucasus region. Thus, the Caucasus region might act as a migratory bridge for influenza virus transmission when birds aggregate in high concentrations in the post-breeding, migrating and overwintering periods. Since August 2009, we have established a surveillance network for influenza viruses in wild birds, using five sample areas geographically spread throughout suitable habitats in both eastern and western Georgia. We took paired tracheal and cloacal swabs and fresh feces samples. We collected 8343 swabs from 76 species belonging to 17 families in 11 orders of birds, of which 84 were real-time RT-PCR positive for avian influenza virus (AIV). No highly pathogenic AIV (HPAIV) H5 or H7 viruses were detected. The overall AIV prevalence was 1.6%. We observed peak prevalence in large gulls during the autumn migration (5.3–9.8%), but peak prevalence in Black-headed Gulls in spring (4.2–13%). In ducks, we observed increased AIV prevalence during the autumn post-moult aggregations and migration stop-over period (6.3%) but at lower levels to those observed in other more northerly post-moult areas in Eurasia. We observed another prevalence peak in the overwintering period (0.14–5.9%). Serological and virological monitoring of a breeding colony of Armenian Gulls showed that adult birds were seropositive on arrival at the breeding colony, but juveniles remained serologically and virologically negative for AIV throughout their time on the breeding grounds, in contrast to gull AIV data from other geographic regions. We show that close phylogenetic relatives of viruses isolated in Georgia are sourced from a wide geographic area throughout Western and Central Eurasia, and from areas that are represented by multiple different flyways, likely linking different host sub-populations.
Citation: Lewis NS, Javakhishvili Z, Russell CA, Machablishvili A, Lexmond P, et al. (2013) Avian Influenza Virus Surveillance in Wild Birds in Georgia: 2009–2011. PLoS ONE 8(3): e58534. doi:10.1371/journal.pone.0058534
Editor: Ralph Tripp, University of Georgia, United States of America
Received: November 23, 2012; Accepted: February 5, 2013; Published: March 13, 2013
Copyright: © 2013 Lewis et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by a Wellcome Trust Fellowship WT089235MF http://www.wellcome.ac.uk/index.htm and by NIAID-NIH contract No. HHSN266200700010C “NIAID Centres of Excellence for Influenza Research and Surveillance” http://www.niaid.nih.gov/LabsAndResources/resources/ceirs/Pages/crip.aspx. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors hereby declare that co-author Prof Ron A. M. Fouchier currently serves on the Editorial Board for PLOS ONE. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.