The flu is back in the news lately — specifically an outbreak of swine influenza in Mexico and parts of the United States.
What is swine flu? It is a type A influenza virus that infects pigs. In general, swine flu has a high infection rate but a low death rate; it is most commonly seen in late fall and winter (similar to human influenza). Pigs can be infected by other strains of flu — including avian influenza and human influenza. When viruses are passed between different species, they can swap genes — known as reassorting — and create new viruses.
Currently, there are four main strains of influenza type A that infect pigs.
Swine influenza does not normally infect humans, though there have been cases in the past. In 1976, there was an outbreak of swine flu among soldiers at Fort Dix in New Jersey — it circulated for approximately one month, leaving one dead. 1988 saw multiple human infections in Wisconsin, with evidence of at least one case of a human patient passing the virus on to some health care workers.
Symptoms of swine flu in humans are generally similar to symptoms of regular seasonal influenza. This can include: fever, lethargy, coughing.
In general, cases of swine flu in humans is rare. Before December 2005, the CDC (U.S. Centers for Disease Control) reported approximately one case of human swine influenza every one to two years. Between December 2005 and February 2009, however, the CDC had twelve reported cases of swine flu.
You cannot catch swine flu from eating pork — the virus is killed at cooking temperatures of 160 degrees Fahrenheit.
The disease is transmitted directly from pigs to people (and vice versa). The virus is most likely to be transmitted when people are in close proximity with infected pigs — working on farms, visiting livestock exhibits. Humans can pass swine influenza in the same way regular influenza is passed along — for example, coughing or sneezing without covering your mouth or touching your mouth after touching something that has the flu virus on it.
Vaccines for human influenza generally don’t work to protect against swine flu — the swine flu, while similar in many ways to human flu, is not the same thing. There are medications available to treat human influenza that also treat swine flu.