Pirtle E C, Hill H R, Swanson M R, van Deusen R A
Bull World Health Organ. 1976;53(1):7-11.
Previous reports have established that swine in the midwestern states of the USA have a high incidence of classical swine influenza and that swine become infected with Hong Kong-like influenza viruses when these are prevalent in the human population. This investigation was undertaken to estimate, on the basis of 2245 sera collected randomly from swine going to slaughter in the USA during the summer months of 1974, how many of the animals had haemagglutination-inhibiting (HI) antibodies against swine influenza and Hong Kong influenza viruses. Based on HI titres of 20 or greater, our serological survey revealed that swine influenza virus infection was widespread throughout the USA, since 20.45% of the sera tested had positive HI titres. However, serological evidence of infection of swine with Hong Kong-like viruses was present in only 2.63% of the sera tested.
先前的报告已经证实，美国中西部各州的猪群中经典猪流感发病率很高，而且当人类中流行香港型流感病毒时，猪会感染这种病毒。本次调查旨在根据1974年夏季从美国待宰猪群中随机采集的2245份血清，估算有多少动物具有针对猪流感和香港型流感病毒的血凝抑制（HI）抗体。根据HI效价为20或更高，我们的血清学调查显示猪流感病毒感染在美国广泛存在，因为20.45%的检测血清HI效价呈阳性。然而，仅2.63%的检测血清中有猪感染香港型病毒的血清学证据。
