Mapping the spatial distribution of the Japanese encephalitis vector, Culex tritaeniorhynchus Giles, 1901 (Diptera: Culicidae) within areas of Japanese encephalitis risk

Abstract

BackgroundJapanese encephalitis (JE) is one of the most significant aetiological agents of viral encephalitis in Asia. This medically important arbovirus is primarily spread from vertebrate hosts to humans by the mosquito vector Culex tritaeniorhynchus. Knowledge of the contemporary distribution of this vector species is lacking, and efforts to define areas of disease risk greatly depend on a thorough understanding of the variation in this mosquito’s geographical distribution.ResultsWe assembled a contemporary database of Cx. tritaeniorhynchus presence records within Japanese encephalitis risk areas from formal literature and other relevant resources, resulting in 1,045 geo-referenced, spatially and temporally unique presence records spanning from 1928 to 2014 (71.9% of records obtained between 2001 and 2014). These presence data were combined with a background dataset capturing sample bias in our presence dataset, along with environmental and socio-economic covariates, to inform a boosted regression tree model predicting environmental suitability for Cx. tritaeniorhynchus at each 5 × 5 km gridded cell within areas of JE risk. The resulting fine-scale map highlights areas of high environmental suitability for this species across India, Nepal and China that coincide with areas of high JE incidence, emphasising the role of this vector in disease transmission and the utility of the map generated.ConclusionsOur map contributes towards efforts determining the spatial heterogeneity in Cx. tritaeniorhynchus distribution within the limits of JE transmission. Specifically, this map can be used to inform vector control programs and can be used to identify key areas where the prevention of Cx. tritaeniorhynchus establishment should be a priority.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2086-8) contains supplementary material, which is available to authorized users.

Influence of Host and Environmental Factors on the Distribution of the Japanese Encephalitis Vector Culex tritaeniorhynchus in China

“…A previous work mapped the distribution of Cx. tritaeniorhynchus within JE risk areas [ 78 ]. However, Tibet, Xinjiang and Qinghai province were not taken into consideration in this study.…”

Mapping Disease Transmission Risk of Nipah Virus in South and Southeast Asia

“…Biosurveillance data for Nipah outbreaks and seropositive Pteropus bats ( n = 51) (1998–2014) were acquired from the Institute of Epidemiology, Disease Control and Research (IEDCR) (Dhaka, Bangladesh) [ 57 ], the World Health Organization [ 16 ], and a variety of diverse literature sources [ 8 , 13 , 58 , 59 , 60 , 61 , 62 , 63 ]. Vector-borne and zoonotic agents are spatially dependent on the geographic distribution of both their vectors and hosts.…”

Comparing pseudo-absences generation techniques in Boosted Regression Trees models for conservation purposes: A case study on amphibians in a protected area

“…Even though the use of AUC to evaluate discrimination performance of SDMs has been questioned [ 29 , 48 ], this metric is used in several recent papers, dealing with biodiversity conservation (e.g. [ 26 – 28 ]) or other research fields [ 49 , 50 ], even when the authors themselves state that the absence data they use may not reflect real absences [ 28 ]. We used AUC as discrimination metric for the BRT models obtained because, even though it should not be used to compare models for different species in presence-background models [ 29 ], it can still be used to compare different modelling approaches applied to the same species at the same extent [ 48 ], which is one of the main purposes of this paper.…”