Malaria risk 'depends on house'

According to researchers from the Wellcome Trust, differences in households can account for around a third of the variations in attack rates by malarial mosquitoes.  Dr Ian Hastings of the London School of Hygiene and Tropical Medicine told the BBC:

"We don't yet know exactly what makes the difference between a good or a bad house. But a lot probably depends on whether there is a mosquito-breeding site in the back yard, the quality of the building and whether insecticides or other repellents are used.

"Identifying and improving factors that put some homes at much lower risk than others would go a long way towards relieving the burden of disease in children living under such conditions."

Quite. We've known for a long time that the most effective way of tackling malaria is to spray the insides of houses with DDT.

This helps prevent mosquitoes from entering dwellings and it repels or kills those insects that do make it inside. Because it minimises the chances of humans being bitten, it effectively prevents the transmission of the malarial parasite, making it an excellent tool for preventing the spread of the disease.

India, for example, started a nationwide programme of indoor DDT spraying in the 1950s, which it has continued to this day. Despite the fact that its population has mushroomed to over a billion in this period, deaths from malaria have decreased to a few thousand each year.

What a shame, then, that the WHO's Roll Back Malaria programme has not embraced fully DDT use. Instead, it has fixated on insecticide-treated bednets, which are both difficult to distribute and unreliable.

Let's hope that this bit of new research brings a bit of the focus away from bednets towards making dwellings less mosquitoe-friendly. DDT has got to be a central part of any such strategy.