リモートセンシングとGISのジャーナル

概要

Climate, Landscape and the Environments of Visceral LeishmaniasisTransmission in India, Using Remote Sensing and GIS

Palaniyandi M*, Anand PH, Maniyosai R

Background: The Indian sub-continent is prone to the occurrences of chronic Visceral Leishmaniasis (VL) or Kalaazar, and geographical distribution of disease is endemic in the states of Bihar, West Bengal, Uttar Pradesh, Jharkhand, Delhi, Gujarat, Madhya Pradesh and Kerala in India. The world distribution of Kala-azar chronic cases occurring in the countries, such as, Brazil, India, Nepal, Bangladesh and Sudan, and the 90% of the disease has been mainly affected the children of below 9-15 years old, and it has been causing 50% of the cases turn to become deaths incidents occurred annually in India. Visceral Leishmaniasis (VL), a chronic disease caused by Leishmania donovani parasites is transmitted by female phlebotomine sandfly, Phlebotomous argentipes. It has been claimed heavy death toll of human lives in South-east Asia, especially in India.

Materials and methods: Visceral Leishmaniasis database was developed in the Dbase format using the MS Excel software and later on imported to the MapInfo Professional 4.5 GIS software platform and Arc View 3.2 Spatial analyst software platform for mapping the Visceral Leishmaniasis epidemics from 1950 to 2012. The VL epidemic data was overlaid on the IRS WiFS data of indigenous satellite remote sensing, and the NDVI value was used for spatial auto correlation analysis.

Results and discussion: The Visceral Leishmaniasis vector (sandfly) abundance has been found in the period of months between June and September, and the best fit for the distribution of P. martini is the dry season composite NDVI 0.07-0.38 and LST 22-33°C with a predictive value of 93.8%, and the best fit for P. orientalis is the wet season composite NDVI -0.01 to 0.34 and Land Surface Temperature (LST) 23°C -34°C The predictive climate model shows the best fit with the average altitude (12 m-1900 m), average annual mean temperature (15°C-30°C), annual rainfall (274 mm -1212 mm), average annual potential evapotranspirations (1264-1938 mm) and readily available soil moisture (62-113 mm) for P. martini and average altitude (200 m-2200 m), annual rainfall (I80 mm-1050 mm), annual mean temperature (16°C-36°C) and readily available soil moisture (67-108 mm), alluvial and black cotton soils dark coloured alkaline in nature (pH 7.2-8.5), calcareous with chief inorganic constituents of silicon, iron and aluminium most suitable for both P. orietalis and Phlebotomus papatasi. The stratification of Kala-azar transmission risk areas was classified, based on the climate variables, and the spatial relationship between the climate variables and VL statistically significance with 93.8%, accuracy.

Conclusion: The longevity and survival of vector populations of Kala-azar has been geographically controlled by the climate (temperature, relative humidity, saturation deficiency, and rainfall), soil types and soil moisture. These climate variables and soil types have been progressively affect the vegetation growth and density, and then the conditions on the surrounding environment. Geographical information systems (GIS) and remote sensing were used to stratify a region into different areas of transmission risk, thereby providing a guideline to mapping the areas under the risk of visceral leishmaniasis transmission in India.