An Investigation of <i>Culicoides</i> (Diptera: Ceratopogonidae) as Potential Vectors of Medically and Veterinary Important Arboviruses in South Africa

Abstract

<i>Culicoides</i>-borne viruses such as bluetongue, African horse sickness, and Schmallenberg virus cause major economic burdens due to animal outbreaks in Africa and their emergence in Europe and Asia. However, little is known about the role of <i>Culicoides</i> as vectors for zoonotic arboviruses. In this study, we identify both veterinary and zoonotic arboviruses in pools of <i>Culicoides</i> biting midges in South Africa, during 2012–2017. Midges were collected at six surveillance sites in three provinces and screened for <i>Alphavirs</i>, <i>Flavivirus</i>, <i>Orthobunyavirus</i>, and <i>Phlebovirus</i> genera; equine encephalosis virus (EEV); and <i>Rhaboviridae,</i> by reverse transcription polymerase chain reaction. In total, 66/331 (minimum infection rate (MIR) = 0.4) pools tested positive for one or more arbovirus. Orthobunyaviruses, including Shuni virus (MIR = 0.1) and EEV (MIR = 0.2) were more readily detected, while only 2/66 (MIR = 0.1) Middelburg virus and 4/66 unknown <i>Rhabdoviridae</i> viruses (MIR = 0.0) were detected. This study suggests <i>Culicoides</i> as potential vectors of both veterinary and zoonotic arboviruses detected in disease outbreaks in Africa, which may contribute to the emergence of these viruses to new regions.