Serum samples of 585 swine were collected from a slaughter house in Kumamoto prefecture during a period from January to December 1979.
They were examined for retention of antibodies againist influenza virus of Hong-Kong type, Russian type and Swine type. The following results were obtained.
1) The antibodies of Swine type were detected all over the prefecture and the positive rate of antiboby was 73.9%. The positive rates of antibodies of the Hong-Kong type and Russian type which were the human contageous types were 14.0% and 1.7%, respectively.
2) The survey on the antibodies to swine influenza by months revealed a high retention rate during the season from December to March.
3) The antibodies of Swine type influenza virus were for the first time confirmed in the northern part of the prefecture during the period from July to September, 1977, and then amounted to as high as 40.5% in November 1977 and 73.9% in 1979.
4) The antibodies to Russian type was for the first time confirmed in April 1979, which was concentrated in the swine-keeping farmers in the southern territory of the prefecture. Positive trials are suggested for the isolation of these viruses in view of the actual detection of the antibodies.
