Results and discussion
Through a molecular analysis and using BLASTn we confirmed the first EHV-3 record in Chile, since three identical the sequences of gGgene were obtained from three mares. The consensus sequence was 99.7% (428/429 bp) identical to a homologue haplotype from Brazil (GQ336877), and clustered into a monophyletic group with EHV-3 sequences obtained from Japan, Russia and Brazil (Fig. 2). Our sequence, clearly differs from types 1, 4, 8 and 9 of equine herpesviruses, and was deposited in GenBank with accession number MZ747033.
Although the presence of aborted fetuses as a result of EHV-1 was reported in Chile decades ago (Ruiz, 1998), this is the first study that molecularly characterizes a EHV-3 strain in the country isolated from equines with genital lesions. Likewise, EHV-3 has been described in countries such as Japan, in horses with symptoms of ECE (Kirasawa, 2017). On the other hand, in Argentina, positive females were diagnosed with a subclinical infection, without clinical symptoms (Barrandeguy, 2010).
The first detections of EHV-3 occurred in the USA, Canada and Australia in 1968 (Kirasawa, 2017). Currently, EHV-3 is distributed worldwide, and its pathogenesis, genetics and antigenic features vary with respect to the other types of EHV. The virus is also highly contagious (Sijmons, 2014), so it is likely its prevalence in Chile is underestimated. Because the virus abruptly hinders reproductive activity, it might negatively impact farms with infected animals (Barrandeguy, 2010). For this reason, preventive actions such as vaginal washing, that reduces the risk of transmission, should be carried out routinely (Toishi, 2017). As our finding suggests that Chilean equine populations would be at risk of infection, studies looking to understand the prevalence of this pathogen along the country must be undertaken.
In conclusion, the presence of EHV-3 is confirmed for the first time in Chile. The recognition of the pathology as well as its association with venereal transmission will afford to deduce areas of distribution and, therefore, evaluate the potential for reproduction risks in the Chilean equine population.