More than medicine to beat malaria
By Wendy Barnaby
Medical science will have to work alongside social and economic development to lessen the threat of malaria, Dr Sonya Taylor told the British Science Festival yesterday.
The incidence of malaria has decreased by 25 per cent in the last decade, because of bednets, increased coverage of insecticide sprays, new combination drug therapies, increasing awareness and socioeconomic development. “It’s the entire infrastructure of a country that needs to be looked at,” said Taylor.
The malaria mortality rate is still astronomical, however. Infected children under the age of five in developing countries still die at the rate of 90 per cent. World Health Organisation figures show that, worldwide, the estimated number of deaths from parasitic diseases such as malaria are comparable to those from cancer and coronary heart disease. Low-income countries are disproportionately affected.
Dr Taylor, who studies how to disrupt the malaria parasite’s life cycle in the mosquito, said that a cure is still escaping scientists because the parasite is so clever.
“This is a single-celled parasite, yet it’s been tricking us for the past 130 years,” she said. “That’s because it can change what it presents on the surface of an infected red blood cell. It will present antigens. Our antibodies will mount an immune response to these; but the parasite will change what it presents on the surface, making our response useless, so we have to mount a different response. This makes it extremely difficult to find a vaccine and to treat it with drugs.”
In the face of these scientific stumbling blocks, said Dr Taylor, we need to look more broadly than medical research for ways to lower mortality.
The anopheles mosquito is creeping northwards in Africa. It needs a temperature of 20 degrees Celcius and humidity of 80 per cent to survive. “It is very particular. It needs both these aspects of climate,” said Taylor. Rich countries have been able to afford draining wetlands to decrease the danger, but poor countries have not.