Linking vector favourable environmental conditions with serological evidence of widespread Bluetongue virus exposure in livestock in Ecuador

Abstract

Despite knowledge of Bluetongue disease (BT) in Latin America, little information is available on the actual spread and overall burden. As a vector-borne disease, high-risk areas for BT will coincide with favourable environmental conditions for the prevailing vector. In Ecuador, information on the presence of BTV is limited to singled out virological findings. In this study, we obtained serological evidence for BT virus exposure derived from the passive surveillance system of national veterinary services aimed at detecting reproductive-vesicular diseases, including BT, for differential diagnosis. Bioclimatic factors relevant for Culicoides development as the main vector and the host abundance in parish level were taken as risk factors and analysed using a logistic regression model. Results reveal widespread evidence of bluetongue virus exposure that geographically matches favourable vector ecosystems between 12°C and 32°C. The variables relevant for the prediction of BTV riskiest areas include cattle population, maximum temperature of the warmest month, minimum temperature of the coldest month, temperature seasonality, and precipitation of the driest month. This analysis, the first of its kind for an Andean country with diverse ecosystems, can inform initial strategic approaches for targeted surveillance and control measures considering a one-health approach.