Protecting older children and adults with insecticide-treated bed nets may be an effective way to combat malaria, a study has shown. The research, published today in the open access journal PLoS Medicine, suggests that protecting half of all older children and adults would also protect the wider community from malaria, which kills over one million people each year.
Current international guidelines recommend providing subsidised bed nets for young children and pregnant women in order to achieve over 80% coverage in these high-risk groups. However, this strategy appears to overlook the benefits of protecting the rest of the population.
Using recently-developed models of mosquito behaviour and mortality, researchers at the Ifakara Health Research and Development Centre in Tanzania, led by Dr Gerry Killeen, a Wellcome Trust researcher from the School of Biological and Biomedical Sciences, Durham University, have shown that if use of the nets can be achieved by 35-65% of older children and adults, this would substantially enhance the protection of the more vulnerable groups, too. Most human-to-mosquito transmission originates from adults and children over five years of age, who constitute the bulk of the population and are more attractive to mosquitoes.
"Insecticide-treated nets can protect not only the individuals and households that use them, but also members of the surrounding community," says Dr Killeen. "This is because they kill adult mosquitoes directly or force them to undertake longer, more hazardous foraging expeditions in search of blood to feed on and aquatic habitats in which to breed."
Dr Christian Lengeler, a co-author from the Swiss Tropical Institute, agrees: Nets have an altruistic value and this needs to be considered when planning programmes."
Malaria is caused by infection with a parasite carried in the salivary glands of the mosquito. The parasite is transmitted when a person is bitten by an in
Contact: Craig Brierley