Bluetongue virus in Culicoides spp. in Manabí province, Ecuador

Abstract

Bluetongue is a viral disease that affects sheep, cattle and other domestic or wild ruminants. Different species of Culicoides transmit the virus (BTV). High BTV seroprevalence was found in farms of Manabí and other two provinces of Ecuador, but the presence of the virus in the Culicoides spp. vector has not been reported. In the current study, the main goal was to demonstrate the presence of BTV in Culicoides in Ecuador for the first time and characterize the species of Culicoides collected in farms located in the central-east area of Manabí province. Six farms were selected to be monitored by BTV c-ELISA. All the 100 tested animals were positive. Using a CDC trap with ultraviolet light placed in three BTV-positive farms for three nights, 2240 specimens of Culicoides were collected. Six different Culicoides species have been identi-fied, which were presented in different abundance percent: 62% C.insignis; 7% C. batesi; 1.8% C.foxi; 1.8% C.diabolicus; 15.48% C.crepuscularis; 12% C.antunesis. These last two species have been identified for the first time in Ecuador. Q-PCR detected BTV RNA in the homogenates of female midges collected in each farm, so it was demonstrated that the epidemiological cycle of the virus is completed; since female midges infected with BTV were found, it is too a novel result for Ecuador. Keywords: Bluetongue, BTV, Culicoides, cattle, real-time PCR, competitive ELISA, Ecuador, Manabi