Urban Bill Brieger | 11 Sep 2009 07:44 am
As Africa Becomes More Urban, What Happens to Malaria?
Africa is one of the fastest urbanizing regions of the world. Estimates are that nearly 40% of Africans live in urban areas today. This number is expected to exceed 50% by 2030. UN Habitat reports in State of the World’s Cities that African urbanization is often focused on the major cities like the capital, with major slum development, not a place where anopheles mosquitoes are comfortable.
Studies have shown that malaria is not generally an urban disease because dense, congested and dirty urban settings do not favor the breeding of anopheles mosquitoes. When malaria occurs in urban areas, it is often found in very focal transmission sites, for example, in places where urban agriculture is practiced.
Luanda in Angola presents a good example of the urban phenomenon as seen in the chart. Although much of the surrounding country to the north and east are highly endemic areas, Luanda itself was found to have a prevalence of only 3.5%. There are variations as expected with the somewhat less dense suburbs having greater, but still not high levels of prevalence.
What is important is that this city contains up to half of the country’s 16+ million inhabitants and is growing. Ironically, while prevalence is low, national strategy documents cite malaria as a cause of nearly one-quarter of child deaths in Luanda. Clearly there are diagnostic challenges.
Unfortunately the absence of malaria in urban areas does not preclude spending money on malaria treatment, as was documented in Nairobi. We documented a similar challenge in Lagos, Nigeria where prevalence among children aged 1-6 years was only 0.9%, but community members had spent thousands of dollars in preceding weeks on antimalarial medicines to treat fevers that they suspected as being malaria.
Moving forward toward malaria elimination will require countries to account for increasing urbanization. Increased use of diagnostic tools will be required to ensure appropriate and targeted use of anti-malarial drugs. Vector control activities will need to be strategic and focus specifically on anopheles’ verified breeding sites.
While increasing urbanization may result in proportionately fewer people at risk from malaria, population growth generally will unfortunately guarantee that large rural populations remain at risk. National malaria strategies need to take these varying ecologies into account if they are going to eliminate malaria.