London School of Hygiene & Tropical Medicine

Artemisinin combination therapies (ACTs) could be almost as effective in reducing transmission of malaria as insecticide-treated bednets (ITNs) in areas of low transmission, a study based on data from Tanzania has found. In high transmission areas, long-acting antimalarial regimens may be needed to achieve significant transmission reductions.

Experts from the London School of Hygiene & Tropical Medicine, with colleagues from Imperial College, London (UK) and Radboud Unversity in Nijmegen in the Netherlands used mathematical modelling to predict the potential impact on transmission outcomes of introducing ACT as the first-line treatment for uncomplicated malaria in six areas of Tanzania. The effects of ACT were estimated from clinical trial data. The findings of the study are published today in the journal PLoS Medicine.

The reductions in infection and clinical episodes of malaria were predicted to be highest in areas of low transmission, where it was estimated that a 53% decrease in clinical episodes might occur if all current treatments were switched to ACT. This compared to 21% in the areas with the highest transmission.

Lucy Okell, Research Degree Student at the London School of Hygiene & Tropical Medicine and lead author of the study, commented: 'Overall, we predict that at existing treatment rates, a 100% switch to ACT from non-artemisinin drugs could reduce the rate of clinical episodes of malaria by between 21 and 53% if a short-acting ACT such as artemether-lumefantrine was used. The impact is smallest in the highest transmission settings, but it could be up to three times greater in these areas if a long-acting ACT regimen was used. As endemic countries gear up for malaria eradication, a target called for by the Bill and Melinda Gates Foundation in 2007, it will be important to know how choice of first-line treatment can help reach this goal'.