Epidemiology &Surveillance Bill Brieger | 21 Jul 2012 06:14 pm
Mapping Malaria – targeting interventions
The World Bank has announced a project in Nigeria to map the location of high risk populations in order to target interventions more effectively. According to the Bank, “In Nigeria, populations at greatest risk for HIV comprise 3.4% of population but account for up to 40% of new infections.” We hope that such efforts will help decrease disease and not increase stigma and discrimination. But clearly, mapping is an important tool to understand a health problem.
Mapping on the broadest sense has been undertaken for malaria. An earlier incarnation of African mapping was MARA, which was founded on the idea that mapping could help target resources. More recently the Malaria Atlas Project (MAP) has tried to refine the mapping process drawing on a wide variety of epidemiological studies in endemic countries. MAP has moved beyond Africa and looks at both P. falciparum and P. vivax.
Detailed country maps from MARA and MAP on a country by country basis help us see different transmission and seasonal patterns of disease. From this we can target regions in a country that may benefit more from indoor residual spraying or intermittent preventive treatment.
The interesting thing about malaria is that transmission can vary even on a micro level. Urban malaria is a case in point, where there are fewer anopheles mosquito breeding sites in densely populated urban slums, and more in areas where people have gardens.
Even in rural areas transmission can vary by proximity to the watery breeding sources of mosquitoes. Factors ranging from deforestation to rice farming play a localized role in transmission mapping. This should lead to spatial targeting of interventions.
We need to carry mapping and thereby appropriate interventions to the community level to have the greatest effect. At present we are of lucky to get any supplies of malaria commodities into a country and distributed to the next administrative level. Micro mapping and planning may sound like a dream in this context, but if we are to succeed in eliminating the disease, we may need to carry the fight from one neighborhood, hamlet or block to the next. Such surveillance is the key to a malaria free future.