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Figure 2. Migration routes of Asian birds. A) Distribution and
migration routes of bar-headed geese (courtesy of P. Leader). B) The Asia-Pacific
region contains >240 species of migratory birds. The 3 flyways run
primarily in a north-south direction, overlapping and extending from Australia/New
Zealand to India, Central Asia, and Siberia. The outbreak of highly pathogenic
(HP) H5N1 in migratory waterfowl at Qinghai Lake, China, affected primarily
bar-headed geese (Anser indicus); however, other species, including
gulls and ducks, were affected (16,17).
The outbreak started in early May 2005, and by June >5,000 birds had
died. The birds exhibited neurologic signs, inability to stand, diarrhea,
and death. Systemic infection was detected in all organs tested. C) Bar-headed
goose infected with HP H5N1 influenza virus. D) Immunostain of goose pancreas,
using H5 monoclonal antibodies (magnification ×400). (C and D, courtesy
of H. Chen). Countries shown in red have had outbreaks of HP H5N1 since
2004. The geographic range of H5N1 may be extended by bar-headed geese
or by ducks that are less susceptible to lethal infection.
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