Environment &Epidemiology Bill Brieger | 19 Feb 2009 07:14 am
Micro-Geography and Malaria
We know at the global level that malaria currently clusters in countries that are relatively closer to the equator rather than in temperate or colder regions. A study out of Papua New Guinea (PNG) emphasizes the need to learn about local variations in malaria distribution as an aid to proper planning and intervention.
Meyers and colleagues found that, “malarial infection is significantly and independently associated with lower elevation and greater distance from administrative centre in a rural area in PNG.” They considered that higher elevations would be hillier with less opportunity for water collection, and locations on the outskirts of villagers may be closer to swampy or agricultural lands where mosquito breeding would be greater.
Local geography also plays a role in the distribution of urban malaria. A recent study in Ouagadougou, Burkina Faso found that malaria was “focused in areas which are irregularly or sparsely built-up or near the hydrographic network” such as urban gardens as well as in poorer neighborhoods. The solutions to urban areas are multi-sectoral according to Donnelly et al. : “Urban malaria is uniquely amenable to prevention and control as the existing health, urban planning, agricultural and governance structures present opportunities for collaborative approaches that can include both the community and the substantial private sector.”
The East African Highlands are another example of geographical variations of malaria distribution in a country. These are areas where malaria is seasonal. Recent investigation has shown how climate change may actually be changing the seasonal distribution of rain, vector and thus malaria. Deforestation can also create geographical variations in malaria distribution.
Natural and man-made variations in geography within countries and even communities have important implications for the planning, targeting and timing of malaria control activities. Clinics in certain areas may need more stocks of ACTs. Supplies of drugs, nets and spray should be timed in advance of known seasonal onset of malaria in other areas. As elimination comes closer to reality this micro-planning for micro-geographical areas will be the only way to keep the disease under control. It will also require a multi-sector approach.