Avian Influenza: Multiple Strains Cause Different Effects Worldwide [Updated May 14, 2004] [open pdf - 2KB]
"Since the fall of 2003, highly pathogenic avian influenza (H5N1) has spread throughout Asia, infecting mostly poultry but also a limited number of humans. Officials are concerned that the virus could mutate to allow human-to-human transmission. The situation in Asia has raised the awareness of this disease in the U.S. In February and March 2004, a low pathogenicity avian flu surfaced in Delaware, Maryland, and New Jersey (H7N2), and another strain was found in Pennsylvania (H2N2). One highly pathogenic strain (H5N2) surfaced in Texas. In British Columbia, Canada, a highly pathogenic strain (H7N3) was discovered in March, and an H5 strain was found in May. While low pathogenicity avian flu (LPAI) is not uncommon, the strain in Texas is the first highly pathogenic (HPAI) case in the U.S. since 1983-1984. Federal and state officials have responded by depopulating (destroying) flocks, imposing quarantines, conducting extensive surveillance, and providing funding. On April 1, USDA [United States Department of Agriculture] announced that the HPAI outbreak in Texas was eradicated. In Canada, however, the disease has spread extensively and depopulation is underway. Only a few strains of avian flu have been known to affect humans, and no humans in the U.S. have been known to be infected. In Canada, however, two workers in the response were infected and have recovered. Because human infection is possible, public health guidelines have been published. This report will be updated as events warrant."
CRS Report for Congress, RS21747
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