Journal of Vector Borne Diseases (Sep 2006)
Mapping of risk prone areas of kala-azar (Visceral leishmaniasis) in parts of Bihar state, India: an RS and GIS approach
Abstract
Background & objectives: The kala-azar fever (Visceral leishmaniasis) is continuing unabated inIndia for over a century, now being largely confined to the eastern part of India mainly in Bihar stateand to some extent in its bordering states like West Bengal and Uttar Pradesh. Two study sites namelyPatepur block in Vaishali district with high endemicity in northern part and Lohardagga block inLohardagga district with absolute non-endemicity in southern part of Bihar were selected for thestudy with the following objectives : (i) to study the macro-ecosystem in relation to distribution ofvector —Phlebotomus argentipes; (ii) to identify/map the risk prone areas or villages in a block forquick remedial measures; and (iii) to make use of satellite remote sensing and GIS to demonstratethe utility for rapid assessment of landuse/landcover and their relation with the incidence of kalaazarleading to the mapping of risk prone areas.Methods: Indian Remote Sensing (IRS)-1D LISS III satellite data for the periods of March andNovember 2000 were analysed in Silicon graphic image processing system using ERDAS software.False color composites (FCC) were generated and landuse/landcover was assessed using Maximumlikelihood supervised classification techniques based on ground truth training sets. During the studythe GIS functions are used to quantify the remotely sensed landscape proportions of 5 km2 buffersurrounding each known group of villages of high occurrence of sandflies in endemic and nonendemicstudy sites. Instead of traditional ground based survey methods to vector surveillance, thepresent study used a combination of remote sensing (RS) and geographical information system (GIS)approach to develop landscape predictors of sandfly abundance—an indicator of human vector contactand as a measure of risk prone areas.Results: Statistical analysis using the remotely sensed landscape variables showed that rural villagessurrounded by higher proportion of transitional swamps with soft stemmed edible plants and banana,sugarcane plantations had higher sandfly abundance and would, therefore, be at higher risk proneareas for man-vector contact.Interpretation & conclusion: The present study clearly brought out the usefulness of satellite remotesensing technology in generating the crucial information on spatial distribution of landuse/landcoverclasses with special emphasis on indicator landcover classes thereby helping in prioritising the areato identify risk prone areas of kala-azar through GIS application tools.
