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

<p>Abstract</p> <p>Background</p> <p>An improved understanding in transmission variation of kala-azar is fundamental to conduct surveillance and implementing disease prevention strategies. This study investigated the spatio-temporal patterns and hotspot detection for re...

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Main Authors: Bhunia Gouri Sankar, Kesari Shreekant, Chatterjee Nandini, Kumar Vijay, Das Pradeep
Format: Article
Language:English
Published: BMC 2013-02-01
Series:BMC Infectious Diseases
Subjects:
Online Access:http://www.biomedcentral.com/1471-2334/13/64
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author Bhunia Gouri Sankar
Kesari Shreekant
Chatterjee Nandini
Kumar Vijay
Das Pradeep
author_facet Bhunia Gouri Sankar
Kesari Shreekant
Chatterjee Nandini
Kumar Vijay
Das Pradeep
author_sort Bhunia Gouri Sankar
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>An improved understanding in transmission variation of kala-azar is fundamental to conduct surveillance and implementing disease prevention strategies. This study investigated the spatio-temporal patterns and hotspot detection for reporting kala-azar cases in Vaishali district based on spatial statistical analysis.</p> <p>Methods</p> <p>Epidemiological data from the study area during 2007–2011 was used to examine the dynamic space-time pattern of kala-azar outbreaks, and all cases were geocoded at a village level. Spatial smoothing was applied to reduce random noise in the data. Inverse distance weighting (IDW) is used to interpolate and predict the pattern of VL cases distribution across the district. Moran’s <it>I</it> Index (Moran’s <it>I</it>) statistics was used to evaluate autocorrelation in kala-azar spatial distribution and test how villages were clustered or dispersed in space. Getis-Ord <it>G</it><sub><it>i</it></sub><sup><it>*</it></sup><it>(d)</it> was used to identify the hotspot and cold spot areas within the study site.</p> <p>Results</p> <p>Mapping kala-azar cases or incidences reflects the spatial heterogeneity in the incidence rate of kala-azar affected villages in Vaishali district. Kala-azar incidence rate map showed most of the highest endemic villages were located in southern, eastern and northwestern part of the district; in the middle part of the district generally show the medium occurrence of VL. There was a significant positive spatial autocorrelation of kala-azar incidences for five consecutive years, with Moran’s <it>I</it> statistic ranging from 0.04-0.17 (<it>P</it> <0.01). The results revealed spatially clustered patterns with significant differences by village. The hotspots showed the spatial trend of kala-azar diffusion (<it>P</it> < 0.01).</p> <p>Conclusions</p> <p>The results pointed to the usefulness of spatial statistical approach to improve our understanding the spatio-temporal dynamics and control of kala-azar. The study also showed the north-western and southern part of Vaishali district is most likely endemic cluster region. To employ exact and geographically suitable risk-reduction programmes, apply of such spatial analysis tools should suit a vital constituent in epidemiology research and risk evaluation of kala-azar.</p>
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spelling doaj.art-de0c247d84c34a98a6e06e99fee85efc2022-12-21T23:31:12ZengBMCBMC Infectious Diseases1471-23342013-02-011316410.1186/1471-2334-13-64Spatial and temporal variation and hotspot detection of kala-azar disease in Vaishali district (Bihar), IndiaBhunia Gouri SankarKesari ShreekantChatterjee NandiniKumar VijayDas Pradeep<p>Abstract</p> <p>Background</p> <p>An improved understanding in transmission variation of kala-azar is fundamental to conduct surveillance and implementing disease prevention strategies. This study investigated the spatio-temporal patterns and hotspot detection for reporting kala-azar cases in Vaishali district based on spatial statistical analysis.</p> <p>Methods</p> <p>Epidemiological data from the study area during 2007–2011 was used to examine the dynamic space-time pattern of kala-azar outbreaks, and all cases were geocoded at a village level. Spatial smoothing was applied to reduce random noise in the data. Inverse distance weighting (IDW) is used to interpolate and predict the pattern of VL cases distribution across the district. Moran’s <it>I</it> Index (Moran’s <it>I</it>) statistics was used to evaluate autocorrelation in kala-azar spatial distribution and test how villages were clustered or dispersed in space. Getis-Ord <it>G</it><sub><it>i</it></sub><sup><it>*</it></sup><it>(d)</it> was used to identify the hotspot and cold spot areas within the study site.</p> <p>Results</p> <p>Mapping kala-azar cases or incidences reflects the spatial heterogeneity in the incidence rate of kala-azar affected villages in Vaishali district. Kala-azar incidence rate map showed most of the highest endemic villages were located in southern, eastern and northwestern part of the district; in the middle part of the district generally show the medium occurrence of VL. There was a significant positive spatial autocorrelation of kala-azar incidences for five consecutive years, with Moran’s <it>I</it> statistic ranging from 0.04-0.17 (<it>P</it> <0.01). The results revealed spatially clustered patterns with significant differences by village. The hotspots showed the spatial trend of kala-azar diffusion (<it>P</it> < 0.01).</p> <p>Conclusions</p> <p>The results pointed to the usefulness of spatial statistical approach to improve our understanding the spatio-temporal dynamics and control of kala-azar. The study also showed the north-western and southern part of Vaishali district is most likely endemic cluster region. To employ exact and geographically suitable risk-reduction programmes, apply of such spatial analysis tools should suit a vital constituent in epidemiology research and risk evaluation of kala-azar.</p>http://www.biomedcentral.com/1471-2334/13/64Kala-azarSpatial statisticsSpatio-temporalHotspot
spellingShingle Bhunia Gouri Sankar
Kesari Shreekant
Chatterjee Nandini
Kumar Vijay
Das Pradeep
Spatial and temporal variation and hotspot detection of kala-azar disease in Vaishali district (Bihar), India
BMC Infectious Diseases
Kala-azar
Spatial statistics
Spatio-temporal
Hotspot
title Spatial and temporal variation and hotspot detection of kala-azar disease in Vaishali district (Bihar), India
title_full Spatial and temporal variation and hotspot detection of kala-azar disease in Vaishali district (Bihar), India
title_fullStr Spatial and temporal variation and hotspot detection of kala-azar disease in Vaishali district (Bihar), India
title_full_unstemmed Spatial and temporal variation and hotspot detection of kala-azar disease in Vaishali district (Bihar), India
title_short Spatial and temporal variation and hotspot detection of kala-azar disease in Vaishali district (Bihar), India
title_sort spatial and temporal variation and hotspot detection of kala azar disease in vaishali district bihar india
topic Kala-azar
Spatial statistics
Spatio-temporal
Hotspot
url http://www.biomedcentral.com/1471-2334/13/64
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