SINGAPORE – The White House announced Tuesday its plan to prevent a bird flu pandemic in the United States. Facts on bird flu:
-- Avian influenza is an infection caused by viruses.
-- There are many different subtypes of type A influenza viruses.
-- There are 16 known HA subtypes and nine known NA subtypes of influenza A viruses.
-- Influenza A (H5N1) virus is an influenza A virus subtype that occurs mainly in birds, is highly contagious among birds, and can be deadly to them
-- H5N1 has caused the largest number of detected cases of severe disease and death in humans
-- There currently is no commercially available vaccine to protect humans against H5N1 virus that is being seen in Asia and Europe.
-- H5N1 virus has crossed the species barrier to infect humans on at least three occasions in recent years
-- Since 1959, instances of human infection with an avian influenza virus have been documented on only 10 occasions
-- The current outbreaks of H5N1 virus began in December 2003 and were first recognized in January 2004
-- 1997: First documented outbreak of human infections with H5N1 in Hong Kong
Sources: CDC, WHO
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