London School of Hygiene & Tropical Medicine

Modern houses with metal roofs and finished walls may reduce the risk of children in sub-Saharan Africa contracting malaria, according to new research published in PLOS Medicine.

The study, co-authored by the London School of Hygiene & Tropical Medicine and led by the University of Oxford, found modern housing reduced the odds of malaria in children by more than 9% when compared to more traditional thatched houses.

Insecticide-treated bed nets and house spraying have been effective in reducing the prevalence of malaria since the turn of the 21^st century, but other approaches are needed for sustainable elimination of the mosquito-transmitted, parasitic disease. Some evidence has suggested that modern houses may protect against the parasite but few studies have rigorously evaluated the association between improved housing and malaria risk.

In this study, the researchers analyzed malaria prevalence and housing using data collected in 29 surveys carried out in 21 African countries between 2008 and 2015. Information on malaria status-as tested using a blood smear or rapid test-was available for 139,318 children under age five living in 84,153 households. The proportion of children with malaria detectable in their blood varied by survey, ranging from 0.4% to 45.5% among children living in modern houses, to  0.4% to 70.6% among children living in traditional homes.

Across all surveys modern housing, defined as a house with a finished wall, roof and floor, was associated with a 9% to 14% reduction in the odds of malaria infection, after controlling for household wealth and use of insecticides. By comparison, children sleeping under insecticide-treated bed nets had a 15% to 16% reduction in odds of testing positive for the disease.

Co-author Associate Professor Christian Bottomley from the London School of Hygiene & Tropical Medicine said: "There is a surprising lack of evidence to show that good housing reduces malaria risk. Our study has helped to fill this gap.  We now need to translate the link between housing quality and malaria into ways of improving housing to prevent malaria. Fortunately, several trials of housing interventions are already underway."

Lead author Lucy Tusting from the University of Oxford, said: "Good housing is a core pillar of public health, but is not used widely for malaria control. Well-built housing can block mosquitoes from entering homes and prevent them from transmitting malaria to the people who live there. This is the first study to compare housing and insecticide-treated nets for malaria control across a range of countries in sub-Saharan Africa. Our study suggests good housing could be an important tool in tackling malaria. This is a welcome finding at a time when we are facing increasing resistance to our most effective insecticides and drugs."

The authors note that the effectiveness of improving housing will vary depending on the location. While many mosquitoes enter homes to bite humans at night, outdoor malaria transmission is more common in some places, meaning interventions centered on the home will have less impact. Although the authors controlled for household wealth, the findings are likely to be partly explained by wealthier households having more modern houses and this must be further investigated in future studies.

The study was funded by the UK Medical Research Council.

Publication

Lucy S Tusting, Christian Bottomley, Harry Gibson, Immo Kleinschimdt, Andrew Tatem, Steve W Lindsay, Peter W Gething. Housing Improvements and Malaria Risk in Sub-Saharan Africa: A Multi-Country Analysis of Survey Data. PLOS Medicine. DOI:10.1371/journal.pmed.1002234