The spread of avian influenza viruses (AIV) in nature is intrinsically linked with the migratory movements of waterbirds. Waterbirds are the reservoirs for low pathogenic avian influenza viruses (LPAIV) in nature and their migration facilitates the circulation of LPAIVs between breeding grounds at high latitude and wintering areas at lower latitudes. There is growing evidence that migratory birds may also be directly involved in the spread of highly pathogenic avian influenza (HPAIV) of the lethal subtype H5N1. The large-scale outbreak of HPAIV H5N1 at Qinghai Lake, China in 2005 killed over 6,300 wild birds, among them the Bar-headed goose, great cormorant, great black-headed gull, brown-headed gull and ruddy shelduck. Qinghai Lake is renowned habitat for migrating and breeding waterbirds, and poultry are rarely found in this arid steppe region, suggesting that migratory wild birds may have introduced the virus. Since 2005, wild birds with natural infections of HPAIV H5N1 have been reported from 38 countries in Asia, Europe, Africa and the Middle East, typically in the spring months coinciding with northward migration. In view of species such as the mallard, common teal and Northern pintail to carry the virus with few or no clinical symptoms, understanding the role of migratory waterbirds in the ecology of H5N1 is a critical area of research.
The transnational movement of HPAIV H5N1, which has a fatality rate of 60% in infected humans and up to 100% in infected poultry, presents a major challenge for public health and agricultural biosecurity worldwide. The virus has not yet gained capacity for human-to-human transmission, but has become endemic in countries such as Indonesia and Egypt. How wild birds contribute to the global spread of HPAIV H5N1 is not well understood. Consequently, telemetry studies of wild birds have been adopted by the U. S. Geological Survey in partnership with the Food & Agriculture Organization (FAO) of the United Nations to better understand the spread of AIV along migration flyways. The movement of waterbirds is tracked using GPS satellite transmitters that offer fine scale spatial data of breeding and wintering grounds and the connecting migratory pathway. Such spatio-temporal studies of the movement of wild birds in relation to outbreaks aim to clarify the extent to which waterbirds are effective hosts for the transmission and spread of HPAIV H5N1. To date, over 500 transmitters have been deployed on 24 species of waterbirds in 12 countries world-wide. To find out more, click on a study site on the map and follow the birds as they migrate.
Disclaimer: These data and maps are provided as a public service and educational tool for the general community interested in migratory birds. Any use of this information for scientific analyses, manuscripts, or presentations requires permission from the teams of principal investigators that collected the datasets.
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U.S. Department of the Interior |
U.S. Geological Survey