Interrupting malaria transmission

4 October 2007

One of the major public health challenges in the developing world is malaria. Malaria parasites go through several stages in their development. When in their asexual stage, they can cause the symptoms and disease associated with malaria infections. Sexual stage parasites (gametocytes) do not cause symptoms, but parasites in this stage are responsible for the transmission of the disease. Jan Teun Bousema has studied the occurrence and factors influencing the spread of malaria through gametocytes. He measured the amount of people carrying gametocytes using a newly developed technique and found that many more people carry gametocytes than previously thought. These newly detected gametocytes circulate at low densities, but Bousema has shown that these low densities are sufficient to infect mosquitoes very efficiently, explaining the easy transmissibility of malaria. The proportion of humans that can transmit malaria may be 4-30 fold higher than previously suspected. This study has also shown that for several weeks after treatment with the current malaria medicines, patients still carried small amounts of gametocytes, which means that they could still transmit the disease.