[Systems analytical investigation of the effect of countermeasures against the AIDS epidemic among homosexuals].
In Japan, the AIDS (Acquired Immunodeficiency Syndrome) epidemic among haemophiliacs has been the most urgent issue, because of the large number of haemophiliacs with AIDS. However, after governmental approval of the production of heated coagulating agents in 1985 and 1986, the prime object of prevention against the AIDS epidemic shifted from transmission through coagulation agents to that through sexual contacts. In order to investigate the most appropriate countermeasures against the AIDS epidemic among homosexuals in Japan, the numbers of HIV (Human Immunodeficiency Virus)-infected cases and AIDS cases in the future were estimated, and changes of the future numbers of HIV-infected persons and AIDS cases by behavior of homosexuals were compared using a systems analytical method. The methods of estimation and comparison are similar to those of R. M. Anderson and others, using numerical analysis of a mathematical model consisting of differential equations. They assumed a closed homosexual group whose members seldom have contact with members of other homosexual groups, but we assumed an open homosexual group whose members are being infected by other groups, because this assumption was more appropriate to the situation of homosexual society in Japan. The results showed that the prevalence number of HIV-infected cases would be about 1,800, that the prevalence number of AIDS cases would be about 100 among 100,000 homosexuals at 20 years after the beginning of the AIDS epidemic, and that the most effective countermeasure was reducing the frequency of sexual contacts among members or taking prophylactic measures during sexual contacts. These prevalence numbers of HIV-infected cases and AIDS cases would be reduced to between 1/4 and 1/2 of the above-mentioned calculated values by promotion of that countermeasure.
Morio
S
S
Department of Hygiene, Faculty of Medicine, Tottori University.
Soda
K
K
Hashimoto
S
S
Fukutomi
K
K
Nakayama
H
H
D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology* / Q000517:prevention & control; D001521:Behavior Therapy; D006716:Homosexuality; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D012725:Sexual Behavior; D013597:Systems Analysis