Perspectives on the Changing Landscape of Epizootic Hemorrhagic Disease Virus Control

Leela E Noronha,Lee W Cohnstaedt,Juergen A Richt,William C Wilson

doi:10.3390/v13112268

Abstract

Epizootic hemorrhagic disease (EHD) is an insect-transmitted viral disease of wild and domestic ruminants. It was first described following a 1955 epizootic in North American white-tailed deer (Odocoileus virginianus), a species which is highly susceptible to the causative agent of EHD, epizootic hemorrhagic disease virus (EHDV). EHDV has been detected globally across tropical and temperate regions, largely corresponding to the presence of Culicoides spp. biting midges which transmit the virus between ruminant hosts. It regularly causes high morbidity and mortality in wild and captive deer populations in endemic areas during epizootics. Although cattle historically have been less susceptible to EHDV, reports of clinical disease in cattle have increased in the past two decades. There is a pressing need to identify new methods to prevent and mitigate outbreaks and reduce the considerable impacts of EHDV on livestock and wildlife. This review discusses recent research advancements towards the control of EHDV, including the development of new investigative tools and progress in basic and applied research focused on virus detection, disease mitigation, and vector control. The potential impacts and implications of these advancements on EHD management are also discussed.

Highlights

Epizootic hemorrhagic disease virus (EHDV) belongs to the genus Orbivirus of the family Reoviridae. It is the causative agent of epizootic hemorrhagic disease (EHD), a disease of wild and domestic ruminants transmitted by Culicoides spp. biting midges (Diptera: Ceratopogonidae; [1])
North American white-tailed deer (WTD; Odocoileus virginianus) represent the species most severely impacted by EHDV, but several ruminant species, including domestic cattle, can be infected and develop clinical disease
This vaccine, which was efficacious in protecting WTD from viremia and clinical disease following an experimental challenge with a virulent EHDV-2 virus, has additional benefits including potential Differentiating Infected from Vaccinated Animals (DIVA) compatibility and wider safety margins than live-attenuated vaccines

Summary

Introduction

Epizootic hemorrhagic disease virus (EHDV) belongs to the genus Orbivirus of the family Reoviridae. It is the causative agent of epizootic hemorrhagic disease (EHD), a disease of wild and domestic ruminants transmitted by Culicoides spp. biting midges (Diptera: Ceratopogonidae; [1]). North American white-tailed deer (WTD; Odocoileus virginianus) represent the species most severely impacted by EHDV, but several ruminant species, including domestic cattle, can be infected and develop clinical disease (reviewed in [2]). EHDV-infected cattle experience less severe disease, with some exceptions [3–6], including infections with Ibaraki virus (IBAV), a strain endemic to Asia which sporadically causes an acute febrile syndrome resembling bluetongue in cattle [7,8]. Several new tools and models have been developed and used to generate discoveries with the potential to translate into applied methods to control EHDV transmission and clinical disease. This review discusses some of the research developments from 2016 to present that may inform efforts toward the management and control of EHD

EHD’s Evolving Epidemiology

Cattle In Vivo Studies

Molecular Vaccine and Diagnostic Tools

Developments in Vector Control

Findings

Outlook