Reducing malarial transmission in Africa

There are 300 million cases of malaria each year worldwide, causing one million deaths. Around 90% of these deaths occur in Africa, mostly in young children. One of the greatest challenges facing Africa in the fight against malaria is drug resistance; resistance to chloroquine (CQ), the cheapest and most widely used antimalarial, is common throughout Africa, and resistance to sulfadoxine-pyrimethamine (SP), the first-developed and least expensive alternative to CQ, is also increasing. These trends have forced many countries to change their treatment policies and use more expensive drugs, including drug combinations that will hopefully slow the development of resistance and minimize transmission of resistant parasites.

In this month’s premier open-access journal PLoS Medicine Colin Sutherland and colleagues from the London School of Hygiene and Tropical Medicine report the results of a randomized, controlled trial of 497 children in Uganda treated with one of two leading combination therapies. One regimen was an artemisinin-based combination consisting of artemether and lumefantrine (co-artemether, trade names CoArtem and Riamet). The other was a combination of CQ and SP – currently under consideration in several African countries, largely due to its low cost. Altogether, the six-dose regimen of co-artemether was highly effective at reducing whether and how long children had gametocytes – the infective form of the malarial parasite – in their blood. The numbers of gametocytes carried and how able they were to infect mosquitoes 7 days later was also reduced by the six dose regimen.

Although the results are promising, some patients may have difficulty taking a six-dose regimen, and as it also needs oily food for adequate absorption there might be inadequate drug levels in the blood of many treated individuals. The authors conclude that although co-artemether as a first-line treatment is not likely to reduce overall transmission of Plasmodium falciparum within the community it might reduce selective transmission of resistant parasites in treated patients.