We evaluated the association between HIV-1 RNA copies/mL in men and heterosexual transmission to their female partners among 493 couples in Thailand. Husbands were identified as HIV-positive when they were screened as blood donors; nearly all were infected with HIV subtype E. Wives had no known risks for HIV infection other than sex with their husbands. In multivariate analysis, each log10 increment of HIV RNA in the man was associated with an 81% increased rate of HIV transmission to his wife (odds ratio = 1.81, 95% confidence interval: 1.33-2.48). No transmission occurred at viral loads below 1094 copies/mL, and a dose-response effect was seen with increasing viral load in the man. In multivariate analysis, a history of a sexually transmitted disease in the man or woman, longer duration of hormonal contraceptive use, and the woman's onset of sexual activity at less than 20 years of age were also associated with increased seropositivity of the wife.

Glutathione transferases (GSTs) (E.C.2.5.1.18) are multifunctional enzymes involved in the detoxification of many exogenous and endogenous compounds. This study aimed to characterize several new GSTs from Anopheles cracens, a major Thai malaria vector formerly known as Anopheles dirus. The three recombinant enzymes obtained were from the epsilon, theta and omega classes. They showed 80-93% identity to orthologous An. gambiae GSTs. AcGSTE2-2 possessed peroxidase activity that cannot be detected for the An. gambiae AgGSTE2-2. AcGSTT1-1 had high activity toward several substrates that are specific for mammalian theta class. The AcGSTO1-1 can use 1-chloro-2,4-dinitrobenzene, dichloroacetic acid, and hydroxyethyl disulfide substrates. The enzymes bound but did not metabolize the organophosphate temephos. The epsilon AcGSTE2-2 functioned as a peroxidase and DDT metabolizing enzyme. The theta AcGSTT1-1 functioned not only as peroxidase but also acted as a binding protein for organophosphates. The omega GST had thiol transferase activity suggesting a role in oxidative stress response.

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