House modifications for preventing malaria

What is the aim of this review?

House modifications, such as screening (covering potential house entry points for mosquitoes with netting or mesh), or the use of alternative construction materials, may contribute to reducing the burden of malaria. They work by blocking mosquitoes from entering houses, and reducing the number of bites householders receive indoors. Some of the house modifications under consideration additionally aim to kill any mosquitoes that attempt to enter houses by incorporating insecticide into the modification.

Key messages

Screening windows, doors, eaves and ceilings to prevent mosquitoes entering the house may reduce malaria transmission and illness in people living in the house, based on evidence from two studies conducted in Africa. Four trials awaiting publication are likely to enrich the current evidence base.

What was studied in the review?

This review summarized studies investigating the effects of house modifications on human malaria outcomes. If studies additionally reported the effect of the house modifications on mosquitoes (those with potential to carry malaria), or householders' views, we also summarized this data. After searching for relevant studies, we identified six studies conducted in sub‐Saharan Africa, two of which have published data, and four of which are not yet in the public domain. All trials assessed screening (of windows, doors, eaves, ceilings, or any combination of these), either alone or in combination with eave closure, roof modification, or eave tube installation (a "lure and kill" device positioned in eave gaps).

What are the main results of the review?

The two trials with published data assessed the effect of screening alone on malaria infection. Both trials showed a reduction in malaria in screened houses, to varying degrees of effect. One trial in Ethiopia showed that people living in screened houses were around 62% less likely to experience an episode of clinical malaria (caused by P falciparum). However, the certainty of this evidence was low due to issues with the study design, and the trial did not study enough people for us to be confident about the results. Another trial in The Gambia showed that people living in screened houses were around 16% less likely to have P falciparum malaria parasites in their blood, and were less likely to experience anaemia. Our confidence in this result was moderate because the trial did not study enough people.

How up to date is this review?

The review authors searched for studies available up to 1 November 2019.