Malaria parasite and HIV virus fuel each other by spreading among people. Scientists from several US universities have developed a model which analyzes how these pathogens interact with each other and how this relation promotes the spread of the diseases in areas of risk.

Researchers studying different models of disease in 200,000 adults in Kenya have reported that HIV-infected persons are particularly vulnerable to malaria because of their weakened immune system, and that malaria can also worsen a person's HIV disease.

Within one particular group, the scientists discovered that malaria may be responsible for almost 5% of HIV infections, and HIV may be behind 10% of malaria episodes. The study also suggests that malaria could contribute to the HIV epidemic in sub-Saharan Africa.

Scientists have known for some time that the immune system suppression caused by HIV virus may increase the risk as well as the malaria infection severity.
But the idea that malaria might be related to HIV transmission is more recent.

People infected with malaria often experience repeated and non lethal outbreaks similar to bird flu. Studies have shown that in people infected with both malaria and HIV, the viral charge in their bodies increases significantly during malaria episodes. Another study has demonstrated that as the HIV virus charge increases, so does the likelihood of HIV transmission through sexual intercourse.

The discovery of a significant HIV-malaria interaction suggests the need for a coordinated approach in fighting both diseases, scientists say.