December 11th, 2006

coyote Phil

AIDS and malaria

I've been saying for years that AIDS transmission is not as simple as catching HIV. AIDS spreads like wildfire in Africa, but not in the US. The explanations offered for this have been

- that the African strain hasn't yet had a chance to spread to the US -- this was certainly false by 1990
- that African men have a culture of secret "on the down low" homosexuality - I doubt this, since homosexuality is still a crime in many parts of Africa, but I don't know
- that Africans in general have more sexual partners than Europeans - if the transmission rate were the same as it is in America, they'd have to have thousands of partners each
- that Africans don't use condoms - again, the difference is too large to be accounted for by this
- that Africans are genetically disposed to catch AIDS, just as they are genetically resistant to malaria - and yet Africans in America don't catch AIDS at a remarkable rate

It's obvious to anyone who thinks about the problem for more than 5 minutes that there is some behavioral or environmental factor that makes it easier to catch AIDS in Africa. I've been saying for years that we should divert some of the money we spend on AIDS research into searching for this factor.

Last week, an article in Science showed that infection with malaria makes AIDS much more transmissible, thus showing that malaria is a major factor in the transmission of AIDS.

What is shocking is not just that it took this long for this link to be discovered. What is shocking is that it keeps being discovered and forgotten. In trying to find the article via Google - because news articles NEVER cite the article they're talking about (whole 'nother rant) - I found articles establishing the malaria-AIDS connection going back to 1990, usually being hyped as "the first" to show a connection. For the curious, this includes

Whitworth JA, Hewitt KA. 2005. Effect of malaria on HIV-1 progression and transmission. Lancet 365(9455):196–197

Weinke T, Schere W, Pohle HD. Malaria tropica in HIV infection (German). Klin Wochenschr. 1990 May17; 68(10):533-6

Maheshwari RK et al. Effect of interferon in malaria infection. Immunol Lett. 1990 Aug;1-3:53-7.

It is true that this particular effect was difficult to track down, because the first thing someone thinks of doing is asking whether AIDs patients have a high incidence of malaria, or whether malaria patients have a high incidence of AIDS. I've heard conflicting information on that. What actually needed to be studied was whether the sexual partners of AIDS patients have a high incidence of malaria.