Introduction
Equine herpesvirus type 3 (EHV-3) belongs to the Order Herpesvirales, Family Herpesviridae and genus Varicellovirus (Davison, 2010). This virus is the causative agent of the equine coital rash (ECE), a venereal disease of worldwide distribution which is characterized by producing lesions in external genitals in foals and mares (Barrandeguy and Thiry, 2012). The main mechanism of transmission is the direct contact of genital mucous membranes during intercourse, or indirectly by fomites (Allen and Umphenour, 2004). Although EHV-3 causes a localized infection, some authors have speculated that systemic alterations such as infertility and abortion do occur as well; yet a systemic pathophysiology is still questionable (Van der Meulen et al., 2006; Léon et al., 2008; Barrandeguy, 2010).
The impact of the disease is associated with forced and temporary interruption of mating activities of the affected stallions and mares, which significantly decreases the number of entries at the end of the season, provokes a delay in delivery dates and a decrease in pregnancy rates (Allen and Umphenour, 2004, Barrandeguy and Thiry, 2012). In the case of infected stallions, a rigid gait, loss of libido and refuse to mate with mares is common (Barrandeguy and Thiry, 2012; Vissani et al., 2018). Diagnosis to distinguish between the different types of equine herpesvirus can be made through PCR (EHV1, EHV2, EHV3, EHV4 and EHV5) (Wagner et al. 1992; Borchers and Slater, 1993; Kirisawa et al., 1993; Wang et al., 2007).
Nowadays, the presence of the disease in Latin America has been detected by molecular tools only in Argentina and Brazil, in clinically healthy mares and from a foal, respectively (Barrandeguy, 2010). To date in Chile, the existence of this disease has not been reported (Berrios, 2005). Therefore, the objective of this study was to molecularly evaluate the presence of this alpha-herpesvirus in equines with the presence of genital lesions compatible with ECE in this country.