AIDS in Thailand[ Back to News Page ] Dated: 10-Jan-2022
About 80% of HIV transmission in Thailand is heterosexual, as compared to about 10% in the USA and some other western countries. So why is the heterosexual transmission rate by unprotected sex is much higher in Thailand than in western countries? One answer is because of a different subtype of HIV virus in Thailand.
AIDS (Acquired Immune Deficiency Syndrome) is caused by the HIV-1 virus (Human Immunodeficiency Virus). However:
There are many sub-types of HIV virus, HIV subtype A, subtype B, and on thru subtype F, plus a subtype O, much like hepatitus has hep-A, hep-B, etc., and this may make HIV in Thailand significantly different from HIV in the west. All these subtypes normally can be tested using HIV Test Kit.
In general, it is common for a particular kind of virus (common flu viruses and others) to have different strains, some of which are much more easily transmitted than others.
In Thailand, the primary means of transmission of HIV is by heterosexual sex, overwhelmingly HIV subtype E. A second group is intravenous drug users (IDU's), most of whom are infected with HIV subtype B, the subtype most widespread in western homosexuals and IDU's, and which is apparently difficult to transmit heterosexually.
In the west, the prevalent HIV subtype B has as its primary means of transmission: anal sex (due to the abrasions of an unlubricated and tight tract which give the virus access to the blood), intravenous drug use (needle sharing between drug users), blood transfusions, hemophilia (people who need blood transfusions and who got donated blood with HIV before the hospitals could detect HIV with HIV Kit), and with heterosexual transmission accounting for only about 10% of all cases. Subtype E is found in only a tiny minority of cases in the west, and is often traceable to travellers from Thailand.
For more than 20 years, Thailand has had HIV subtypes B and E. However, it is subtype E which has taken off in the heterosexual population. This has suggested that there are significantly different degrees of contagiousness between the two subtypes as regards heterosexual transmission.