What is swine flu?
Swine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza viruses. Outbreaks of swine flu happen regularly in pigs. People do not normally get swine flu, but human infections can and do happen. Most commonly, human cases of swine flu happen in people who are around pigs but it’s possible for swine flu viruses to spread from person to person also.
Are there human infections with swine flu in the U.S.?
In late March and early April 2009, cases of human infection with swine influenza A (H1N1) viruses were first reported in Southern California and near San Antonio, Texas. CDC and local and state health agencies are working together to investigate this situation. An updated case count of confirmed swine flu infections in the United States is kept at http://www.cdc.gov/swineflu/investigation.htm. CDC and local and state health agencies are working together to investigate this situation.
How many swine flu viruses are there?
Like all influenza viruses, swine flu viruses change constantly. Pigs can be infected by avian influenza and human influenza viruses as well as swine influenza viruses. When influenza viruses from different species infect pigs, the viruses can reassort (i.e. swap genes) and new viruses that are a mix of swine, human and/or avian influenza viruses can emerge. Over the years, different variations of swine flu viruses have emerged. At this time, there are four main influenza type A virus subtypes that have been isolated in pigs: H1N1, H1N2, H3N2, and H3N1. However, most of the recently isolated influenza viruses from pigs have been H1N1 viruses.
Source:http://pandemicflu.gov/index.html
No comments:
Post a Comment