The nature of malaria

ARE forests linked with the spread of malaria? Or, for that matter, do terrain, agricultural practices, water-bodies or ground-water have any bearing on the disease? Now, a computer-based analysis technology -- the Geographical Information System (GIS) -- may provide answers to these complex questions.

The Malaria Research Centre (MRC) in Delhi is already exploiting GIS to explore the possible influence of several natural factors on the incidence of malaria in Gujarat's Khera district. "We chose this district because there has been a sharp rise in malarial cases there over the last decade," says MRC director V P Sharma.

GIS is essentially a computer software that allows several parameters to be analysed simultaneously. Conventional mapping systems deal with only one or a few variables at a time. GIS can integrate data -- physical and satellite-generated -- of such variables as forest cover, climate and land-use patterns to provide a holistic picture, much to the advantage of both the policy maker and the scientist.

The MRC study, being carried out by the National Institute for Science, Technology and Development Studies (NISTADS) in Delhi, will examine the yearly village-wise data of malarial cases from 1982 to 1992 and see if it is linked with changes in forest cover and meteorological indexes like rainfall.

"Once we understand the interaction between various natural factors and the incidence of malaria, steps can be taken to control it. For instance, an undulating terrain may lead to the formation of puddles or ponds in the rainy season, allowing mosquitoes to breed," says Sharma.

However, for GIS to be useful, the data has to be accurate. Says Subhan Khan, leader of the NISTADS team, "In India, we cannot always be sure of the authenticity of the data. One cannot completely rule out the possibility of the data being doctored by government officials." To guard against this, the team is treating this phase of the project as a pilot stage and only if the results are encouraging, will it cover other parts of the country.