Survey on Hematophagous Vectors and the Viruses They Carry in Equine Animals in Shenzhen

doi:10.3969/j.issn.1001-0769.2025.06.020

Abstract：To ensure the biosecurity of equine animals, this study conducted systematic monitoring of hematophagous mosquitoes, midges, and horseflies in equine animal trading venues in Shenzhen from 2023 to 2024, comprehensively assessing the risk of pathogen transmission of African Horse Sickness (AHS) and West Nile Fever (WNF). Through morphological identification, the species composition and distribution characteristics of vector insects in equine animal trading venues were determined. Randomly selected 20 vector samples were subjected to metagenomic sequencing, while 180 equine blood samples were tested for AHS virus and WNF virus. The results showed that the mosquito community was dominated by Culex genus, with Culex tritaeniorhynchus Giles showing an expanding trend compared to 2023; midge species richness increased from 2 to 4, with Culicoides oxystoma becoming a new dominant species; the horsefly population showed a simplification trend, with Atylotus bivittatus Takahasi disappearing in 2024, while Tabanus indianus Ricardo and Tabanus yamasakii Ouchi remained present. Metagenomic sequencing results showed no viral gene sequences related to humans or animals; all 180 equine blood samples tested negative for AHS virus and WNF virus. Based on the above survey and testing results, combined with the analysis of pathogens of equine-related diseases transmitted by vectors, it is considered that the risk of AHS virus and WNF virus transmission by vectors in equine animal trading venues in Shenzhen is low. However, this result cannot completely exclude the risk of disease introduction, and continuous monitoring should be carried out in combination with vector population dynamics.