Influence of topography on the endemicity of Kala-azar: a study based on remote sensing and geographical information system

Abstract

Abstract. Kala-azar, a fatal infectious disease in many Indian states, particularly in Bihar, West Bengal, Uttar Pradesh, and Jharkhand, is caused by the protozoan parasite Leishmania donovani and transmitted by the sandfly vector Phlebotomus argentipes. The vector is distributed all over the country but the disease is confined to particular zones since before the last century. In this study, parameters such as altitude, temperature, humidity, rainfall and the normalized difference vegetation index (NDVI) were investigated for correlation with the distribution of the disease in the northeastern corner of the Indian sub-continent. Data analysis on Kala-azar prevalence during the period [2005][2006][2007] in the four states showed that the highest prevalence was below 150 m of altitude with very few cases located above the 300 m level. Low NDVI value ranges (0.03-0.015) correlated with a high occurrence of the disease. The maximum temperatures in the affected sites varied between an upper level of 25-29°C and a minimum of 16-20°C. The rainfall in these areas fluctuated between 1154 and 1834 mm. As the disease showed a high correlation with the prevailing topographic conditions, an attempt was made to improve the relative strength of the approach to predict the potential for endemicity of leishmaniasis by introducing satellite imagery complemented with a geographical information system database.

Environmental modelling of visceral leishmaniasis by susceptibility-mapping using neural networks: a case study in north-western Iran

“…In this sense, the knowledge gap which is another drawback in the knowledge-driven approaches was covered in the RBFLN model. Similarly, it has been shown by Bhunia et al (2010) that areas with low altitude, high population density, low vegetation density and low living standard are the most suitable areas for the VL vectors. Sheets et al (2010) also suggested that areas with a low standard of living and with a large number of rainy days are more prone to VL incidence, while Fernandez et al (2010) reported that the distribution of VL vectors is associated with land coverage (bushes and trees) and accessibility to health facility services in densely populated neighbourhoods.…”

“…To specify the input data for the prediction model, the association between VL endemicity and various factors in the literature was explored. In this regard, seven items were deduced from literature to be the critical recognition criteria (CRC) for predictive mapping of VL risk-prone areas: temperature, precipitation, proximity to rivers, altitude, presence of health-centres, land cover and presence of nomads (Sudhakar et al, 2006;Bhunia et al, 2010;Salahi-Moghaddam et al, 2010;Rajabi et al, 2012;Tsegaw et al, 2013).…”

A comparative evaluation of endemic and non-endemic region of visceral leishmaniasis (Kala-azar) in India with ground survey and space technology

“…Analysing the distribution of leishmaniasis (i.e., its identification, standardisation, and location) along with monitoring environmental variables with conventional ground surveys is time consuming, laborious and expensive. With increasing accessibility to new technologies, such as remote sensing (RS), it is possible to monitor landuse features on the earth's surface over various time intervals to develop methods for rapid stratification of highly susceptive areas and to design remedial measures (Bakker et al 2000, De La Rocque et al 2004, Mushinzimana et al 2006, Bhunia et al 2010a). Another recent development is the use of satellite data to acquire increasing amounts of geographical data available in conjunction with geographic information systems (GISs) to assist with interpretation of ecosystems and environmental parameters related to sandfly-genic conditions (Sharma & Srivastava 1997, Bergquist 2001, Moore 2008, Bhunia et al 2011 widespread and combined implementation of RS and GIS technology, professionals have been provided with efficient and accurate tools for mapping, maintaining and managing information on landscape features to further our understanding of the epidemiology for the purpose of controlling of VL in India (Palit et al 2001, Sudhakar et al 2006, Bhunia et al 2010b, 2011.…”

Localization of kala-azar in the endemic region of Bihar, India based on land use/land cover assessment at different scales

“…Environmental factors that directly influence vector density have previously been shown to be associated with risk for kala-azar (Elnaiem et al, 2003;Sudhakar et al, 2006;Bhunia et al, 2010aBhunia et al, ,b, 2011 Sandy areas Naturally occurring granular material in the river basins <1% 3…”

“…Posteriori risk modelling for kala-azar in Africa and Asia suggests that rainfall, altitude and cultivation patterns can predict the transmission rates (Elnaiem et al, 2003;Sudhakar et al, 2006;Bhunia et al, 2010a). Landscape variables such as land use/land cover (LULC) may be particularly important since they are directly linked to vector presence (Feliciangeli et al, 2006).…”