The Spatial Heterogeneity between Japanese Encephalitis Incidence Distribution and Environmental Variables in Nepal



Impoinvil, Daniel E, Solomon, Tom ORCID: 0000-0001-7266-6547, Schluter, W William, Rayamajhi, Ajit, Bichha, Ram Padarath, Shakya, Geeta, Caminade, Cyril ORCID: 0000-0002-3846-7082 and Baylis, Matthew ORCID: 0000-0003-0335-187X
(2011) The Spatial Heterogeneity between Japanese Encephalitis Incidence Distribution and Environmental Variables in Nepal. PLOS ONE, 6 (7). e22192-.

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Abstract

<h4>Background</h4>To identify potential environmental drivers of Japanese Encephalitis virus (JE) transmission in Nepal, we conducted an ecological study to determine the spatial association between 2005 Nepal JE incidence, and climate, agricultural, and land-cover variables at district level.<h4>Methods</h4>District-level data on JE cases were examined using Local Indicators of Spatial Association (LISA) analysis to identify spatial clusters from 2004 to 2008 and 2005 data was used to fit a spatial lag regression model with climate, agriculture and land-cover variables.<h4>Results</h4>Prior to 2006, there was a single large cluster of JE cases located in the Far-West and Mid-West terai regions of Nepal. After 2005, the distribution of JE cases in Nepal shifted with clusters found in the central hill areas. JE incidence during the 2005 epidemic had a stronger association with May mean monthly temperature and April mean monthly total precipitation compared to mean annual temperature and precipitation. A parsimonious spatial lag regression model revealed, 1) a significant negative relationship between JE incidence and April precipitation, 2) a significant positive relationship between JE incidence and percentage of irrigated land 3) a non-significant negative relationship between JE incidence and percentage of grassland cover, and 4) a unimodal non-significant relationship between JE Incidence and pig-to-human ratio.<h4>Conclusion</h4>JE cases clustered in the terai prior to 2006 where it seemed to shift to the Kathmandu region in subsequent years. The spatial pattern of JE cases during the 2005 epidemic in Nepal was significantly associated with low precipitation and the percentage of irrigated land. Despite the availability of an effective vaccine, it is still important to understand environmental drivers of JEV transmission since the enzootic cycle of JEV transmission is not likely to be totally interrupted. Understanding the spatial dynamics of JE risk factors may be useful in providing important information to the Nepal immunization program.

Item Type: Article
Additional Information: Impoinvil, Daniel E Solomon, Tom Schluter, W William Rayamajhi, Ajit Bichha, Ram Padarath Shakya, Geeta Caminade, Cyril Baylis, Matthew PLoS One. 2011;6(7):e22192. Epub 2011 Jul 21. ## TULIP Type: Articles/Papers (Journal) ##
Uncontrolled Keywords: Humans, Encephalitis, Japanese, Incidence, Cluster Analysis, Environment, Temperature, Rain, Seasons, Models, Biological, Time Factors, Agriculture, Nepal
Depositing User: Symplectic Admin
Date Deposited: 11 Apr 2016 14:46
Last Modified: 16 Dec 2022 02:55
DOI: 10.1371/journal.pone.0022192
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3000273