Swine Flu
What is it?
Swine Influenza is a respiratory illness
of pigs caused by a strain of influenza virus.
History
When human and avian influenza viruses infect pigs, they have the potential to swap genes. New pathogens, which are a mix of swine, human and/or avian influenza viruses, can then emerge. The pandemic H1N1 virus is just such an example. In 1998, the first hybrid swine flu virus in N. America was discovered in a factory farm in North Carolina, which made thousands of pigs ill. By early 1999, a triple hybrid virus had spread throughout US pig factories containing gene segments from bird, human and swine flu.
Source
There is now a scientific concensus that the virus of the 2009 swine flu pandemic largely arose from this triple hybrid strain.
Symptoms in animals
Swine flu viruses can cause high levels of illness yet low death rates in pigs. Symptoms include sudden onset of fever, depression, coughing barking, discharge from the nose or eyes, sneezing, breathing difficulties, eye redness or inflammation.
Symptoms in people
The symptoms are similar to seasonal flu. They include fever, aching muscles and a sore throat.
Routes of transmission
Influenza viruses can be directly transmitted from pigs to people and from people to pigs. Human infection from pigs is most likely to occur through close proximity with infected pigs. Human to human, transmission is thought to occur in the same way as seasonal flu M through coughing or sneezing. During the first wave April September of the 2009 pandemic in England, between 144,000 and 670,000 people fell ill. There was another serious wave of illness and death reported in the winter of 2010/11. Worldwide, more than 200 countries have reported laboratory confirmed cases, including at least 15,292 deaths.