[DAR ES SALAAM] A study has shown that using insecticide-treated bednets to protect around half of older children and adults from malaria also protects more vulnerable groups such as children and pregnant women.

Gerry Killeen and colleagues from the Ifakara Health Research and Development Centre in Tanzania published their research in the journal PLoS Medicine this month (3 July).

Current international guidelines recommend providing subsidised insecticide-treated bednets (ITNs) to at least 80 per cent of young children and pregnant women, as they are at the highest risk of contracting malaria.

However, the study shows that if 35–65 per cent of older children and adults also use nets, then younger children and pregnant women are also better protected — both individuals in the same household and members of the surrounding community.

This is because ITNs kill adult mosquitoes and reduce the number of people infected with the malaria parasite, therefore reducing the chance of a mosquito passing the infection on.

Over 80 per cent of human-to-mosquito transmission of malaria occurs when mosquitoes feed on people over the age of five, mainly because they make up the majority of the population, and are also more attractive to mosquitoes, write the authors.

ITNs also force mosquitoes to feed on other mammals that don't host the malaria parasite, reducing the presence of the malaria parasite in mosquito populations.

Killeen told SciDev.Net that 50 per cent of pregnant mothers are now supplied with subsidised ITNs and 85 per cent of people in the area covered by the Ifakara Health Research and Development Centre are using the nets.

"Whenever we visit rural areas where we have our projects, we note that people are using bed nets and that they have developed a strong culture of use," he said.

But Hassan Mshinda, director general of the centre, said there are still questions about how to deliver these interventions in efficient, equitable and locally appropriate ways.

And poor roads via which to deliver nets, shortage of qualified medical personnel and low funding mean that not everyone has access to nets.

Geoffrey Meena, ITNs marketing manager at the nongovernmental organisation Population Service International (PSI) told SciDev.Net many people are beginning to receive bednets through a special subsidy initiative and by raising awareness in remote communities.

According to Meena, last year PSI delivered a total of 200,000 bednets in Tanzania.

Malaria kills over 80,000 children annually in Tanzania and is responsible for 36 per cent of maternal mortality, which stands at 578 per 100,000 live births.