Although malaria has been declining steadily – since 2000 the malaria mortality rate has decreased by 47 per cent worldwide and by 54 per cent in Africa – malaria remains a substantial public health problem. In 2013 there were 198 million cases and an estimated 584,000 malaria deaths.
Reductions in malaria have largely been achieved by scaling-up vector control, including long-lasting insecticidal nets (LLIN) and indoor residual spraying. However both interventions rely on insecticides and their effectiveness is threatened by the growing problem of insecticide-resistant mosquitoes. There is an urgent need to develop more interventions that do not rely on insecticides.
A housing revolution
During the past 30 years a revolution in house design has taken place across Africa. Traditional thatched-roofed houses are being replaced steadily by houses with metal roofs as the continent develops. The aim of the study is to ride this wave of cultural change and further improve the design of houses to make them healthier to live in, potentially improving the lives of millions of people across sub-Saharan Africa.
The number of malaria mosquitoes entering houses at night is a key factor to people getting bitten and becoming sick with malaria. Sleeping under LLIN helps reduce the risk, but people who live in ‘leaky’ houses are still vulnerable. The investigators have previously shown that closing the eaves (the gap between the top of the wall and the roof) and adding mosquito screens can greatly reduce the number of malaria mosquitoes entering a house.
Closing the gap
The team plan to add extra protection to houses, including a metal roof, closed eaves, screened doors and windows, to guard against malaria while providing good ventilation. Malaria cases in children will be compared to those living in houses with thatched roofs and open eaves.
“In addition to measuring the protection provided by ‘good’ housing, its durability and acceptability, the study will assess the cost-effectiveness of housing as a malaria intervention. Most importantly, we will establish a framework for scaling-up such interventions,” said Epidemiologist Dr Margaret Pinder, leading the study at MRC Unit, The Gambia, with the support of co-investigator Professor Umberto D’Alessandro, Unit Director.
“This proposal has been developed in collaboration with partners at the National Malaria Control Programme (NMCP) and we meet with them regularly to update on progress and ‘brainstorm’ problems.”
The study will take place in the Upper River Region and will involve more than 100 rural villages located between the road and the river on both the North and South banks. A total of 800 houses with children are being randomised to the control and intervention arms of the study; consenting and enrolment started on the south bank in March 2015.
Modifications to the 400 intervention houses are underway and will continue during the 2016 dry season. The team will enrol 800 children at the start of the 2016 malaria season, and monitor them during 2016 and 2017. In the dry season of 2018, residents in the control arm will be provided with the intervention if they agree.
A novel intervention
The novel nature of the intervention and the vital follow-up studies makes this a very international collaboration. The investigators from the MRC Unit, The Gambia and Durham University are being supported by an international team including: Jakob Knudsen from the School of Architecture, Copenhagen University, Denmark; a medical anthropologist, Caroline Jones of Oxford University/ KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; and postdoctoral scientist Elisa Sicuri who works with Gambian health economist, Lesong Conteh of Imperial College, London.
“With our international and Gambian collaborators, we intend to demonstrate not only the importance of improved housing in reducing malaria, but also to make strides towards getting such interventions into practice,” said Margaret.
Professor Umberto D’Alessandro said: “Our research programme on malaria is built around questions related to its possible elimination in The Gambia and sub-Saharan Africa and this project fits extremely well into it. I am delighted to be part of this multidisciplinary research team. I am confident that results from this project will provide an additional tool for further decreasing malaria transmission in The Gambia.”