Incidence of visceral leishmaniasis in the Vaishali district of Bihar, India: spatial patterns and role of inland water bodies

Abstract

Abstract. The role of the distribution of inland water bodies with respect to the transmission of visceral leishmaniasis (VL) and its dominant vector, Phlebotomous argentipes, has been studied at the regional scale in Bihar, eastern India. The Landsat TM sensor multispectral scanning radiometer, with a spatial resolution of 30 m in the visible, reflective-infrared and shortwave-infrared (SWIR) bands, was used to identify water bodies using the normalized differential pond index (NDPI) calculated as follows: (Green -SWIR I)/(Green + SWIR I). Nearest neighbour and grid square statistics were used to delineate spatial patterns and distribution of the sandfly vector and the disease it transmits. The female P. argentipes sandfly was found to be associated with the distance from open water and particularly abundant near non-perennial river banks (68.4%; P <0.001), while its association with rivers was focused further away from the water source (χ 2 = 26.3; P <0.001). The results also reveal that the distribution of VL is clustered around non-perennial riverbanks, while the pattern is slightly random around the perennial river banks. The grid square technique illustrate that the spatial distribution of the disease has a much stronger correlation with lower density of open waters surfaces as well as with sandfly densities (χ 2 = 26.0; P <0.001). The results of our study suggest that inland water presence poses a risk for VL by offering suitable breeding sites for P. argentipes, a fact that should be taken into account when attempting to control disease transmission.

Spatial and temporal variation and hotspot detection of kala-azar disease in Vaishali district (Bihar), India

“…In this study we were able to categorize clusters of high incidence rates in the northwestern, eastern and southern part of the district. However, in the southern part of the Vaishali district is surrounded by river Ganga and the north-western part of the district is flanked by the Gandak river that may retain surface moisture condition for the propagation of vector breeding [42]. Furthermore, the area has high population density, and is economically backward with main livelihoods option centered on agriculture and horticulture that may aids to the transmission of disease in this particular area [43,44].…”

Understanding the transmission dynamics of Leishmania donovani to provide robust evidence for interventions to eliminate visceral leishmaniasis in Bihar, India

“…With further refinement, it may be possible to predict VL epidemics on the Indian subcontinent more accurately by monitoring simple meteorological variables (i.e., temperature and rainfall). Spatial patterns of P. argentipes and risk of VL have been studied with respect to proximity to water bodies and other environmental variables in the Vaishali district of Bihar [ 44 , 45 ]. However, such models cannot be used to predict the impact of control and the prospects of elimination.…”

Prone Regions of Zoonotic Cutaneous Leishmaniasis in Southwest of Iran: Combination of Hierarchical Decision Model (AHP) and GIS

“…In the central part of Bihar in eastern India, inland water bodies increased the transmission risk of visceral leishmaniasis (VL) by providing suitable breeding places for the vector Ph. argentipes (48). In the present research study, disease cases and spatial distribution maps of Ph.…”

“…The risk map of Kala-azar was prepared using geo-environmental factors such as land cover/land use, condition of vegetation, surface dampness, climate, illiteracy and unemployment rate of the inhabitants in the Vaishali District of Bihar in India (48).…”