Investigating avian influenza infection hotspots in old-world shorebirds

PLoS One. 2012;7(9):e46049. doi: 10.1371/journal.pone.0046049. Epub 2012 Sep 28.

Abstract

Heterogeneity in the transmission rates of pathogens across hosts or environments may produce disease hotspots, which are defined as specific sites, times or species associations in which the infection rate is consistently elevated. Hotspots for avian influenza virus (AIV) in wild birds are largely unstudied and poorly understood. A striking feature is the existence of a unique but consistent AIV hotspot in shorebirds (Charadriiformes) associated with a single species at a specific location and time (ruddy turnstone Arenaria interpres at Delaware Bay, USA, in May). This unique case, though a valuable reference, limits our capacity to explore and understand the general properties of AIV hotspots in shorebirds. Unfortunately, relatively few shorebirds have been sampled outside Delaware Bay and they belong to only a few shorebird families; there also has been a lack of consistent oropharyngeal sampling as a complement to cloacal sampling. In this study we looked for AIV hotspots associated with other shorebird species and/or with some of the larger congregation sites of shorebirds in the old world. We assembled and analysed a regionally extensive dataset of AIV prevalence from 69 shorebird species sampled in 25 countries across Africa and Western Eurasia. Despite this diverse and extensive coverage we did not detect any new shorebird AIV hotspots. Neither large shorebird congregation sites nor the ruddy turnstone were consistently associated with AIV hotspots. We did, however, find a low but widespread circulation of AIV in shorebirds that contrast with the absence of AIV previously reported in shorebirds in Europe. A very high AIV antibody prevalence coupled to a low infection rate was found in both first-year and adult birds of two migratory sandpiper species, suggesting the potential existence of an AIV hotspot along their migratory flyway that is yet to be discovered.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa
  • Animals
  • Animals, Wild / immunology
  • Animals, Wild / virology*
  • Antibodies, Viral / immunology
  • Asia
  • Charadriiformes / immunology
  • Charadriiformes / virology*
  • Delaware
  • Europe
  • Influenza A virus / immunology
  • Influenza A virus / isolation & purification*
  • Influenza in Birds / epidemiology*
  • Influenza in Birds / immunology
  • Seasons
  • Species Specificity

Substances

  • Antibodies, Viral

Grant support

This survey was conducted under four international programmes including the GRIPAVI project sponsored by grants from the French Ministry of Foreign Affairs, the Technical Cooperation Programme of the Food and Agricultural Organization of the United Nations (UN-FAO) through additional financial resources from the government of France and Sweden, the USAID - and Wildlife Conservation Society - sponsored Global Avian Influenza Network for Surveillance (GAINS), and the EU-funded New Flubird project. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.