Epidemiological patterns of and predictions for AIDS in Mexico

Through February 1988 86.9% of the 1126 reported cases of acquired immune deficiency syndrome (AIDS) in Mexico were transmitted sexually 10.5% by blood transfusions .4% by intravenous drug use and .8% perinatally. 13 cases were in homosexual drug users. Foreign travel was an important factor in Mexicos earliest AIDS cases but it has lost significance as the epidemic has developed. Among the 911 cases in which the risk factor was documented 57.8% were in homosexual men and 23.5% in bisexual men who formed a bridge to the heterosexual population. 2.7% of cases were in women and 2.9% in male partners of infected women. At the beginning of the epidemic in Mexico all AIDS cases were sexually transmitted but the proportion has declined steadily. The 1st perinatal AIDS cases were reported in August 1987. The 1st 2 cases in women were reported in December 1985 when the ratio was 36 in men per 1 in women. By January 1988 the ratio was 15:1. Trends in AIDS cases by age group have remained constant except in children under 15 who comprised 1% of cases in 1985 and 3.8% in January 1988. All Mexican states have reported cases. Some states such as Jalisco and Coahuila have accelerating rates of increase in new cases but the rate of increase has tended to stabilize in the Federal District. AIDS cases are now being reported in rural areas principally among agricultural workers who have been in the US. The proportion of AIDS cases in homosexual men has declined while it has increased in bisexual men. Seroepidemiologic studies to determine the prevalence of human immunodeficiency virus (HIV) infection in selected groups show a prevalence of under 1% in female prostitutes but 16% in male prostitutes. Prevalence rates of HIV infection of 3-33% were found in male homosexuals. Studies of about 100 pregnant women in each of 2 hospitals found none positive for HIV infection. 7.2% of 9100 paid blood donors but less than .1% of volunteer donors tested positive for HIV infection. No prospective studies have been done in Mexico of high risk cohorts. Estimates of the number of seropositive individuals in 1988 ranged from 31600 to 97700 assuming that there were between 28 and 87 infected individuals per AIDS case. Based on reported cases it was predicted that there would be 64304 to 76602 AIDS cases by 1991.