Swine influenza, or flu, is a contagious respiratory disease that affects pigs.
The new virus has genes from North American swine influenza, avian influenza, human influenza and a form of swine influenza normally found in Asia and Europe, said Nancy Cox, chief of the CDC's Influenza Division.
CNN: Among the swine flu mysteries: Why only deaths in Mexico?
The children were infected with a virus known as swine influenza A H1N1, which has a unique combination of genes not previously seen in flu viruses in either humans or swine - although it shares similarities with a virus that has been circulating in pigs since 1999.
The farmer "may have exposed swine on the farm to an influenza virus, " said Dr. Brian Evans of the Canadian Food Inspection Agency.
Already, some Southeastern states -- particularly Georgia, Alabama, Mississippi and Florida -- have been hit hard by the swine flu virus, also known as 2009 H1N1 influenza, perhaps because schools opened earlier there, she said.
Except for hospitalized patients, others with flu-like symptoms are not being tested to confirm they have swine flu, since "virtually all of the influenza that's circulating right now in the United States is the 2009 H1N1 strain, " Schuchat said.
Symptoms of swine flu in humans are expected to resemble regular human seasonal influenza symptoms, including fever, lethargy, lack of appetite, and coughing, the CDC said.
Swine flu is a respiratory disease of pigs caused by type A influenza, according to the CDC.
Swine flu is a respiratory disease which is caused by a strain of the influenza type A virus known as H1N1.
Swine have long been suspected as the ideal mixing vessel for the emergence of new influenza strains.
The group remains quarantined at home, and Health Minister Tony Ryall said 10 students tested positive for influenza A -- the general category of strains that includes the H1N1 swine flu.
CNN: U.S. prepares for possible swine flu epidemic as global cases rise
But the monitoring of birds, pigs, people and the genetics of the influenza virus have all been stepped up in response to recent outbreaks of both swine flu and bird flu.
应用推荐