Equine Coital Exanthema: New Insights on the Knowledge and Leading Perspectives for Treatment and Prevention

Abstract

Equine coital exanthema (ECE) is a highly contagious, venereally-transmitted mucocutaneous disease, characterized by the formation of papules, vesicles, pustules and ulcers on the external genital organs of mares and stallions, and caused by equid alphaherpesvirus 3 (EHV-3). The infection is endemic worldwide and the virus is transmitted mainly through direct contact during sexual intercourse and by contaminated instruments during reproductive maneuvers in breeding facilities. The disease does not result in systemic illness, infertility or abortion, yet it does have a negative impact on the equine industry as it forces the temporary withdrawal of affected animals with the consequent disruption of mating activities in breeding facilities. The purpose of this review is to provide up-to-date relevant information on the knowledge of EHV-3 infection and to analyze new approaches on diagnostics, treatment and prevention in the interest of minimizing the negative consequences of ECE in light of the current situation of the equine industry.

Keywords: EHV-3; equid alphaherpesvirus; equine coital exanthema; equine industry; equine infectious disease; equine reproduction.

Figure 1

Transmission cycle of equid alphaherpesvirus 3 (EHV-3) in mares and stallions.

Figure 2

(1) Equid alphaherpesvirus 3 (EHV-3) infects the stratified epithelium of epidermal tissues present at mucous–cutaneous margins and skin of external genital organs; (2) the virus replicates and laterally spreads; (3) lytic replication occurs and the virus is shed; (4) destruction of epithelial cells elicits a vigorous, localized inflammatory response; (5) the virus does not breach the basal membrane, and thus systemic dissemination is limited; square to dots: After active infection the virus induces latency; the anatomic site has been not yet demonstrated but it has been inferred to be in the sciatic and/or sacral ganglion cells.