- This article refers to flu in pigs. The 2009 outbreak of 'swine flu' is at 2009 pandemic
Swine influenza or swine flu (commonly misspelled swine flue) refers to a range of influenza cases that are caused by viruses endemic to pigs. Swine flu infects some people every year, typically those in close contact with pigs.
The influenza virus can be carried by migratory birds, who are not usually affected. The bird droppings can infect pigs, where the virus may mutate. New strains may be able to infect humans, which is what led to the 2009 H1N1 outbreak.
- Main article: 2009 pandemic
The 2009 Flu outbreak is a new strain of H1N1-type influenza, commonly referred to as "swine flu". This strain mutated out of other strains of swine flu and other influenza viruses.
Cases were found to be made up of genetic elements from four different flu viruses – North American swine influenza, North American avian influenza, human influenza, and a swine influenza virus typically found in Asia and Europe.