The effect of irrigation on malaria vector bionomics and transmission intensity in western Ethiopia

Parasites & Vectors

James W. Kazura¹  Behailu Taye²  Alemayehu Dagne²  Daibin Zhong³  Ming-Chieh Lee³  Guiyun Yan³  Guofa Zhou³  Endalew Zemene⁴  Delenasaw Yewhalaw⁵  Werissaw Haileselassie⁶  Wakgari Deressa⁶ 

[1] Center for Global Health and Disease, Case Western Reserve University, 44106, Cleveland, OH, USA;Department of Biology, Faculty of Natural and Computational Science, Mettu University, Mettu, Ethiopia;Program in Public Health, College of Health Sciences, University of California at Irvine, 92697, Irvine, CA, USA;School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia;School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia;Tropical and Infectious Diseases Research Centre, Jimma University, Jimma, Ethiopia;School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia;

关键词: Mosquito vectors;    Malaria;    Transmission intensity;    Irrigation;    Ethiopia;   

DOI  :  10.1186/s13071-021-04993-y

来源: Springer

【 摘 要 】

BackgroundIrrigation schemes may result in subsequent changes in malaria disease dynamics. Understanding the mechanisms and effects of irrigation on malaria vector bionomics and transmission intensity is essential to develop new or alternative surveillance and control strategies to reduce or control malaria risk. This study was designed to assess the effect of rice irrigation on malaria vector bionomics and transmission intensity in the Gambella Region, Ethiopia.MethodsComparative cross-sectional study was conducted in Abobo District of the Gambella Region, Ethiopia. Accordingly, clusters (kebeles) were classified into nearby and faraway clusters depending on their proximity to the irrigation scheme. Adult mosquito survey was conducted in February, August and November 2018 from three nearby and three faraway clusters using Centers for Disease Control and Prevention (CDC) light traps (LTs). During the November survey, human landing catch (HLC) and pyrethrum spray catch (PSC) were also conducted. The collected mosquitoes were morphologically identified to species and tested for Plasmodium infection using circumsporozoite protein enzyme-linked immunosorbent assay (CSP-ELISA). Furthermore, species-specific polymerase chain reaction (PCR) was performed to identify member species of the Anopheles gambiae complex. Chi-square and t-tests were used to analyze the data using the SPSS version 20 software package.ResultsA total of 4319 female anopheline mosquitoes comprising An. gambiae sensu lato, An. funestus group, An. pharoensis, An. coustani complex and An. squamosus were collected. Overall, 84.5% and 15.5% of the anopheline mosquitoes were collected from the nearby and faraway clusters, respectively. Anopheles gambiae s.l. was the predominant (56.2%) anopheline species in the area followed by An. pharoensis (15.7%). The density of anopheline mosquitoes was significantly higher in the nearby clusters in both HLCs [t(3)  =  5.14, P  =  0.0143] and CDC LT catches [t(271.97)  =  7.446, P  <  0.0001). The overall sporozoite rate of anopheline species from the nearby clusters was 10-fold higher compared to the faraway clusters.ConclusionsSignificantly higher mosquito population density was observed in areas close to the irrigation sites. Sporozoite infection rate in the mosquito population was also markedly higher from the nearby clusters. Therefore, the irrigation scheme could increase the risk of malaria in the area.Graphical abstract

【 授权许可】

CC BY