The HIV found in India is different from that in Thailand. Transmission HIV is an extremely fragile virus it is killed by drying, for example. Thus, transmission requires intimate contact. The major modes of transmission include sexual intercourse, systemic inoculation through IV drug use or transfusion, and vertical transmission from mother to child. There is no evidence for aerosol or insect-borne transmission.
Heterosexual transmission can occur from both male to female and female to male.
Male to female transmission is 2 to 10 times more likely to occur than the reverse. In North America and Europe male to female transmission frequency has been estimated at .001 per act of intercourse, although a recent Thai study of female to male transmission gave the frequency of transmission as .03 to .05 per act. Sexual transmission can be limited by condom use and, to a lesser degree, by extravaginal ejaculation. Sexual transmission via oral routes has been reported, but is probably extremely infrequent. The biological mechanism underlying the sexual transmission of HIV is not completely understood.