Double jeopardy

Malaria can double concentration of HIV

Published: Tuesday 15 March 2005

malaria and human immunodeficiency virus (hiv) infection are both endemic in several countries. While the effects of hiv infection on malaria have been documented, can malaria also enhance hiv transmission and accelerate disease progression? The answer is in the affirmative, according to a recently published article in The Lancet (Vol 365, No 9455).

James G Kublin from the Fred Hutchinson Cancer Research Centre in Seattle, usa and his team conducted a study on 334 people in Malawi, Africa to find out how the malarial parasite influences viral concentrations, or viral load, in hiv -infected adults. For each subject, the hiv concentration in blood was measured three times: during the enrolment visit when the subject was free from malaria parasite; during an episode of malaria and then about 8 weeks later when the subject had been rid of the malarial parasite following treatment. The main parameters measured were the cd 4 count (cd 4 are white blood cells whose number indicate the status of hiv infection) and the viral loads. Their values at the beginning of the study were taken as baseline data.

The findings show the hiv concentration in the blood could double with malaria. The greatest increases occurred when the individuals had had fever; with parasite density more than 2000/l (l is a millionth of a litre) and baseline cd4 counts more than 300 cells/l. The authors also found the increased concentration of hiv could be brought back to baseline values within 8-9 weeks among individuals treated adequately for malaria.

The authors argue that if the increase in viral load during malaria was taken as an indication of disease progression, then hiv infection could be said to have accelerated in malaria-endemic areas. The malarial parasite might promote macrophages (cells that engulf foreign organisms to protect the body) and cd 4 cells to activate viral multiplication, they explained. High parasite density because of malaria was likely to elicit a strong immune response from the body, including fever. This triggers more production of chemicals called cytokines, which are known to promote hiv replication.

The findings underline the importance of coordinated efforts in those areas where both diseases are endemic. James Whitworth of the London School of Hygiene and Tropical Medicine supported the view of Kublin (in the same issue of The Lancet) and speculated that as per the study findings, there is a possibility of as much as 50 per cent increase in hiv transmission during the short period of higher viral load in blood during malaria.

The study has important implications for India, which is malaria-endemic and also has the second-highest number of people with hiv infection. Besides, by increasing hiv concentration, malaria increases the risk to health care providers during blood tests and fluid transfusion.

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