Despite the large number of deaths caused worldwide by AIDS, tuberculosis, and diarrhoeal diseases such as cholera, the biggest infectious-disease killer is still malaria, especially in Africa. Efforts to eradicate the carrier of malaria, a mosquito, have been only partly successful. The standard treatment for malaria has, for many years, been chloroquine, a fairly safe, effective, and cheap drug. Over the 40 years, from the 1940s to 80s, malaria parasites in Africa were highly sensitive to chloroquine. The first case of chloroquine resistance was reported in 1982. In Tanzania, Malawi, South Africa, and Kenya, front-line treatment has been, or is being changed to, a combination of antimalarial drugs - pyrimethamine-sulfadoxine.
Over the past 10 years, there have been many reports that malaria parasites in these countries have become resistant to pyrimethamine-sulfadoxine. An alternative treatment is needed. The difficulties that researchers face in finding an alternative include finding a drug manufacturer willing to provide effective treatments at a price affordable to countries whose funds for purchasing drugs is severely limited: there is no point in effectively testing a “wonder drug” that no one can pay for.
Dr Theonest Mutabingwa and colleagues from the National Institute for Medical Research in Tanzania tested two antimalarial drugs in a study in northeastern Tanzania, at Muheza, among 360 children less than five years old with falciparum malaria (the most severe form of the disease). The children were first given standard pyrimethamine-sulfadoxine treatment, and if their blood did not clear of parasites within seven days and they later developed a second episode of malaria they were given either a repeat dose of the same treatment or a new combination, chlorproguanil-dapsone. Repeat treatment with pyrimethamine-sulfadoxine resulted in only 39% of children being rid of malaria, whereas 93% of those treated with the new treatment (chlorproguanil-dapsone) were cleared of parasites.
The urgency of Mutabingwa and colleagues’ research is underlined by their comments that, “…work on a combination of chlorproguanil-dapsone with artesumate is at an early stage of development. Drug development to international regulatory standards takes time, but Africa is in desperate need of an effective and affordable alternative to pyrimethamine-sulfadoxine.”
Contact: Dr Theonest Mutabingwa, National Institute for Medical Research, Amani Medical Research Centre, PO Box 4, Amani-Tanga, Tanzania; t)+255 27 2641420; F)+255 27 2644 121; E) tkmuta@ud.co.tz
Journal
The Lancet