出版社：Indian Association of Preventive and Social Medicine Uttar Pradesh and Uttarakhand Chapter
摘要：Swine flu, also known as swine influenza, pig influenza, hog flu and pig flu, is a respiratory disease caused by viruses (influenza viruses) that infect the respiratory tract of pigs, resulting in nasal secretions, a barking cough, decreased appetite, and listless behaviour. Swine flu produces most of the same symptoms in pigs as human flu produces in people. Mostly people who are closely associated with pigs (for example, pork processors and farmers) acquire the infection and similarly pigs get infected occasionally human flu infection. The cross-species infections (swine virus to man; human flu virus to pigs) have always been confined to local areas and have not spread across borders in either pigs or humans. Unfortunately, this cross-species situation with influenza viruses has had the potential to change and cause epidemics and pandemics. Most recent pandemic has been reported in 2009, where "swine flu" strain, first seen in Mexico, was termed as H1N1 as it was mainly infecting people and exhibited two main surface antigens, H1 (hemagglutinin type 1) and N1 (neuraminidase type1). This unique eight RNA strands from novel H1N1 flu have one strand derived from human flu strains, two from avian (bird) strains, and five from swine strains. Since then it has been infecting people here and there.
