[单项选择]
Slater Swine influenza (also called swine
flu, hog flu, and pig flu) refers to influenza caused by those strains of
influenza virus, called swine influenza virus (SIV), that usually infect pigs.
Swine influenza is common in pigs in the Midwestern United States (and
occasionally in other states), Mexico, Canada, South America, Europe (including
the United Kingdom, Sweden, and Italy), Kenya, Mainland China, Taiwan, Japan and
other parts of eastern Asia. Mike Smith
Transmission of swine influenza virus from pigs to humans is not common
and properly cooked pork poses no risk of infection. When transmission results
in influenza in a human, it is called zoonotic swine flu. People who work with
pigs, especially people with intense exposures, are at risk of catching swine
flu. Rarely, these strains of swine flu can pass from human to human. In humans,
the symptoms of swine flu are similar to those of influenza and of
influenza-like illness
