Malaria is one of the leading causes of sickness and death in the developing world. Despite modern scientific and technological advances, a child dies of malaria every 50 seconds, even though malaria is preventable and curable. About half of the world's population is at risk of malaria, and in 2008 there were an estimated 243 million cases and 864,000 deaths due to malaria, 89% of which occurred in Africa.
Presently malaria prevention prioritises two main interventions: use of long lasting insecticide-treated bed nets and indoor residual spraying. In addition, malaria drugs are used for prophylaxis, especially for vulnerable groups such as pregnant women in highly endemic areas.
But what is the relationship between malaria and architecture — particularly that of housing design? The widespread increase in inadequate housing in recent decades has significantly contributed to the malaria burden. Could housing then be a third site for intervention?
Past studies showed that malaria is predominantly a rural disease in places such as sub-Saharan Africa, and that Anopheles mosquito breeding decreases with increasing proximity to the centre of urban areas. But analysis of recent data indicates that malaria can no longer be regarded only as a rural phenomenon, and that the urban poor in Africa may be at higher risk for malaria than expected.
A policy brief from the Liverpool School of Tropical Medicine noted that prevalence is highest among the poorest sections of urban society, since they cannot afford protection from malaria through improved housing, and are particularly vulnerable to the impact of ineffective diagnosis and treatment.
An estimated 660 million people will live in urban communities in Africa by 2025, some 450 million of those in inadequate housing, and therefore identification of the risk factors for urban malaria requires urgent attention.
But are simple changes in house designs effective in malaria reduction? Mosquito-proofed houses have the potential for protecting people against malaria.
A study by Steve Lindsay at the London School of Hygiene and Tropical Medicine highlights historic findings and urges us not to forget valuable lessons. Lindsay shows that since the 19th century, it has been demonstrated that people could be protected from malaria by screening their homes against mosquitoes. In fact, there was a 96% reduction in cases of malaria among residents with mosquito-proof houses!
In 1921, researcher Mark Boyd found that better quality housing was associated with protection against malaria in Missouri, USA. The British army also mosquito-proofed their houses in Lahore, Pakistan, in 1925, and this reduced the incidence of malaria by 68%.
The issues about the vector behavioural differences may be raised at this point. The African mosquito Anopheles gambiae, which is one of the world's most efficient and dangerous vectors, is adapted for entering houses at night and feeding on people.
When this mosquito reaches wall in trying to enter a house, it flies upwards, and identifies openings or cracks to fly in, unlike other species that fly off sideways when encoutering a wall. Lindsay notes that preventing this mosquito from entering a house either by installing ceilings or closing eaves should reduce malaria transmission, infection and disease. Also, because most mosquitoes searching for blood fly close to the ground, one of the simplest ways of avoiding mosquito bites is by building homes off the ground.
Another researcher, Yazoume Ye, also suggested that housing characteristics should be taken into account when designing health interventions against malaria. He carried out a study in Burkina Faso comparing the prevalence of malaria infection between children living in mud-roofed houses and iron sheet-roofed houses, and found that children living in iron sheet houses had two times less risk of infection compared to those living in houses with mud roofs.
These studies highlight the importance of simple architectural measures as a means of vector control. If mosquito-proofed housing is used in conjunction with existing methods of control, the reduction in infection could be substantial.
As a corollary, government housing authorities, urban planners and NGOs involved in housing need to be more aware that housing projects are not simply a means of providing shelter, but affect the disease burden of their residents.
Especially in tropical areas, many authorities skimp on ceilings, eaves and raised floors, presuming that these are inessential, decorative features. As research improves on urban malaria, it will become clearer that minimum construction standards must be increased to take transmission factors into account.
It is ARCHIVE's ultimate goal that we raise awareness and implement projects using architectural design as a means of combatting malaria transmission. As World Malaria Day approaches, please join the discussion on Facebook: http://www.facebook.com/archiveinstitute or visit us at http://www.archiveinstitute.org .
Diana Inegbenebor is Research Coordinator in the ARCHIVE Institute UK office. She trained as a physician, worked as a clinician in Nigeria, and gained an MSc in Tropical Medicine and International Health and a Diploma in Tropical Medicine and Hygiene from the London School of Hygiene and Tropical Medicine.
The ARCHIVE (Architecture for Health in Vulnerable Environments) Institute is an international social enterprise working at the intersection between health and housing. ARCHIVE uses housing design as a key strategy for improving health among the world's poor. The ARCHIVE Institute was founded by Jamaican architect Peter Williams in 2006 and operates five regional offices spanning five continents.