抄録
Studies were made on the rise and fall of HI antibody against the A/NJ/8/76 strain of influenza virus in human and porcine sera over a period of July, 1975, to March, 1981. On the basis of the results of these studies, a sero-epidemiological survey was carried out to clarify the state of invasion of this virus in Japan. The results obtained are as follows.
1) Porcine serum samples were collected in between 1977 and 1978 and examined for possession of antibody 32 times or more in titer against the A/NJ/8/76 strain. As a result, there were marked differences in the positive rate (the rate consisted of the number of samples showing an antibody titer of 1: 32 or over to the number of samples examined) among the areas from which the samples had been collected (4-100%)
2) Antibody survey were conducted on swine in various areas over a period of 1979 to 1981. As a result, antibody-positive swine were noticed in every area. The antibody-positive rate exceeded 75% in most of the areas.
3) Hog raisers and their families were examined in July, 1975, and inhabitants of areas at large in November of the same year. As a result, HI antibody was found in no human beings 45 years or less of age, but in some people 46 years and more of age. The antibodypositive rate tended to increase with the advance in age.
4) When the employees of slaughterhouses were examined for possession of HI antibody over a period of January, 1979, to March, 1981, a tendency was shown that the antibody-positive rate increased a little year by year (10.7-20.7%).
5) When a serological survey was conducted on the employees of the slaughterhouse in Asahi City, Chiba Prefecture, once a year for 3 years, a total of 10 persons were found infected with the A/NJ/8/76 strain of influenza virus.
