Detection of bluetongue virus in Culicoides spp. in southern Yunnan Province, China

Ying Liang Duan,Le Li,Hua Chun Li,Zhen Xing Yang,Glenn Bellis

doi:10.1186/s13071-020-04518-z

Abstract

BackgroundCulicoides (Diptera: Ceratopogonidae) are vectors for many arboviruses. At least 20 species are considered as vectors or potential vectors of bluetongue virus (BTV) which cause bluetongue disease in ruminants. A BTV prevalence of 30–50% among cattle and goats in tropical southern Yunnan Province, China, prompted an investigation of the potential BTV vectors in this area.MethodsCulicoides were collected by light trapping at three sites in the tropical region of Yunnan Province. Species were identified based on morphology and DNA sequences of cytochrome c oxidase subunit 1 (cox1). PCR and quantitative PCR following reverse transcription were used to test for the presence of BTV RNA in these specimens. Phylogenetic analysis was used to analyze the cox1 sequences of Culicoides specimens infected with BTV.ResultsApproximately 67,000 specimens of Culicoides were collected, of which 748 were tested for the presence of BTV. Five specimens, including two of Culicoides jacobsoni, one of C. tainanus and two of C. imicola, were identified as infected with BTV. No specimens of C. (subgenus Trithecoides) or C. oxystoma tested were positive for BTV infection.ConclusionsTo our knowledge this is the first report of C. jacobsoni as a potential BTV vector and the fourth report of an association between C. tainanus and BTV, as well as the first direct evidence of an association between BTV and C. imicola in Asia. A fourth potential cryptic species within C. tainanus was identified in this study. Further analysis is required to confirm the importance of C. jacobsoni and C. tainanus in BTV epidemiology in Asia.Graphical

Highlights

Culicoides (Diptera: Ceratopogonidae) are vectors for many arboviruses
Three species belonging to C. subgenus Avaritia were found to be associated with bluetongue virus (BTV) in the tropical area of Yunnan Province, China by reverse transcription-quantitative PCR (RT-qPCR) tests targeting BTV segments 1, 2, and 10
C. jacobsoni is reported as a potential BTV vector for the first time

Summary

Introduction

At least 20 species are considered as vectors or potential vectors of bluetongue virus (BTV) which cause bluetongue disease in ruminants. A BTV prevalence of 30–50% among cattle and goats in tropical southern Yunnan Province, China, prompted an investigation of the potential BTV vectors in this area. Members of genus Culicoides (Diptera: Ceratopogonidae) are vectors for many arboviruses, and at least 50 viruses belonging to families Bunyaviridae, Reoviridae, and Rhabdoviridae have been associated with several species of Culicoides in numerous countries [1, 2]. A BTV prevalence of 30–50% among cattle and goats has been reported in the tropical southern part of Yunnan Province [11, 12], indicating an active cycle of infection and the presence of competent vectors

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