[On the immunoserological modification of the human type A influenza virus in animals (author's transl)].

A total of 207 swine serum samples were collected in July and August, 1977, and examined for the presence of hemagglutination-inhibition (HI) antibody against for the human type A influenza virus. Studies were also made on the differences between the strain of the human type A influenza virus by using ferret, mouse, and chicken antisera. The results obtained are summarized as follows. 1) The rate of swine serum samples positive for HI antibody titer exceeding 1: 32 was the highest, or 70.0%, for the swine type strain. It was 19.3% for the A/PR/8/34 strain, 7.7% for the Hongkong type strain, and 1.9% for the Russian type strain. 2) Forty serum samples, or 19.3% of the 207 samples, showed titers of HI antibody against the A/PR/8/34 strain exceeding 1: 32. They were also positive for HI antibody against the swine type strain, exhibiting titers exceeding 1: 32. 3) Antigen analysis with ferret infection antiserum revealed no production of cross HI antibody among the virus strain mentioned in paragraph 1. 4) Antigen analysis was corned out on mouse and chicken sera immunized four times to the representative strain of the human type A influenza virus. It revealed that cross HI antibody was produced to small extent among the A/NJ/8/76, the A/PR/8/34, and the A/USSR/92/77 strain. The results mentioned above seem to suggest that there may be a problem which await further investigation, concerning the classification of the strains of the human type A influenza virus.