Public health programs in Thailand have led to substantial changes in sexual behavior among young men, especially an increased use of condoms, and the rate of new HIV infections has declined.

Serotyping of group A rotaviruses obtained from stools of 158 diarrheic patients in Chiang Mai, Thailand, by ELISA with monoclonal antibodies revealed a yearly change in the prevalence of individual serotypes. Three unusual human rotavirus strains were isolated. Strain Mc35 had subgroup I-serotype 10 antigen and a long RNA electrophoretic type, a property hitherto found only in bovine rotaviruses. RNA-RNA hybridization tests showed that the strain is more closely related genetically to bovine than to human rotaviruses. Strain Mc323, although serologically closely related to serotype 9, had subgroup I specificity and a long RNA electrophoretic type, a characteristic common to nonhuman rotaviruses. Strain Mc345, with an aberrant RNA pattern possibly due to genome rearrangement, had the same antigenic specificity as Mc323. These 2 strains were genetically very closely related to each other and were more related to porcine than to human rotaviruses. These results provide insights into the evolutionary mechanisms of human rotaviruses.

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We compared HIV prevalence, risk behaviours, and social and sexual norms among nine ethnic minority (Hilltribe) groups in northern Thailand. Communities were selected on the basis of size, ethnicity, development level and geography. Subjects (15-45 years) were stratified by gender and selected by household using two-stage randomization. Forty volunteers were identified in each of 27 villages. Participation was voluntary and informed consent was obtained. HIV infection status was determined using ELISA and Western Blot on saliva samples. Risks for HIV were measured with structured interviews using local languages. Overall HIV prevalence was 23/1080 (2.13%) with an equal male-female ratio. HIV prevalence rates were: Shan 8.75%, Akha 5.0%, Yao 5.0%, Thin 1.25%, Hmong 0.63%, Lahu 0.63%, Lisu 0.63%, Karen 0, and Pa-Long 0. Sex worker use was an HIV risk for men (p = 0.0001), but injecting drug use was not; for women, having been a sex worker was a significant HIV risk (p < 0.0001). HIV rates, social norms and sexual behaviour varied considerably among ethnic groups, as did attitudes toward commercial sex work and use. HIV prevention needs to target the Shan, Akha, and Yao communities, and to focus on reduction of brothel work and use.

To evaluate the association between sexually transmitted diseases that commonly may cause genital ulceration and prevalent and incident HIV infections, we conducted three case control studies in a cohort of 21-year-old male military conscripts in northern Thailand. The men were evaluated at baseline in 1991 and semiannually until their discharge 2 years later. Serologic evidence of infection with herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and HIV were more frequent at baseline in 83 men with a history of genital ulcer than in 97 men without such a history. Seropositivity to H. ducreyi (odds ratio [OR] = 3.46), HSV-2 (OR = 3.83), and syphilis (OR = 1.53) were more common in HIV-positive than HIV-negative men. Men (N = 45) who seroconverted to HIV while in the military were more often seropositive for H. ducreyi and HSV-2 before HIV seroconversion and also were more likely to seroconvert to HSV-2 and H. ducreyi during the same interval as their HIV seroconversion compared with men who remained HIV-negative. These data suggest that HSV-2 and H. ducreyi may be both markers for high-risk sexual behavior and risk factors for HIV infection among young men in Thailand.