Malaria ‘could speed up spread of HIV’

Health services in developing countries should integrate programmes treating HIV/AIDS and malaria, say researchers, following publication of a study showing that having malaria could make people with HIV more likely to transmit the virus.

The study, published last week in The Lancet, showed that levels of the HIV virus in the blood almost doubled when patients got malaria. Eight to nine weeks after being treated for malaria, HIV levels returned to what they were at the start of the study.

Even a temporary increase in virus concentration could increase HIV transmission, warn the researchers, led by Malcolm Molyneux of the Malawi-Liverpool-Wellcome Trust Clinical Research Programme in Malawi.

Molyneux’s team looked at 367 people with HIV in Thyolo District, Malawi. Of these, 148 developed malaria during the study, but the team was only able to collect sufficient information for analysis from 77 of these patients.

The researchers suggest that malaria causes HIV levels to increase because the human body’s immune system produces more white blood cells to attack the malaria parasite. But stimulating the immune system like this activates the HIV virus, which begins replicating.

This increase in viral concentration could, say the researchers, be sustained long enough to increase risk of HIV transmission.

In an accompanying commentary in The Lancet, James Whitworth at the London School of Hygiene and Tropical Medicine, United Kingdom, and Kirsten Hewitt at the Health Protection Agency Centre for Infections, also in London, say that because malaria and HIV affect large numbers of people, even small increases in transmission of HIV are important, so better integration of health services for the two diseases is crucial.

They suggest the temporary increase in viral load reported by Molyneux’s team could equate to about a 50 per cent increase in HIV transmission during this period.

Neil French, of the Malawi-Liverpool-Wellcome Trust laboratories, told SciDev.Net that discovering the exact interaction between malaria and HIV would be difficult because the research would require treating people under study for neither disease.

Such ‘non-intervention’ would be unethical given the increasing availability of HIV and malaria drugs in areas affected by both diseases.

French points out that the two diseases overlap on social as well biological levels. The poorest in society are most likely to be infected by HIV and least likely to have access to bednets to prevent malaria. Disease control programmes, he adds, should come together to provide a comprehensive package of care.

In the developed world, the threat of simultaneous infection with HIV and other diseases has been reduced by use of antiretroviral drugs. In the developing world, however, being infected by both malaria and HIV could be more important because drugs against HIV are not widely available.

French suggests that a pragmatic approach might be to give people with HIV bednets to reduce their chance of getting malaria.

The World Health Organization estimates that together malaria and HIV cause more than four million deaths per year worldwide.

Link to paper by Molyneux et al in The Lancet.

Link to commentary by Whitworth and Hewitt in The Lancet

Reference: The Lancet 365, 233 (2005)

Link to more information about the interactions between malaria and HIV/AIDS