Although equine gastric ulcer syndrome (EGUS) has a known negative impact on equine performance, only a few options exist to treat gastric ulcers in competitive horses and those treatments are mainly focused on supportive care. Importantly, treatment of EGUS can be expensive and does not address the etiology of this syndrome. Therefore, proper knowledge regarding the causal factors in EGUS development is needed for the development of targeted, more efficacious therapeutics.

Recently, we preliminary demonstrated the presence of EHV-2 and EHV-5, two equine gammaherpesviruses that are correlated with “general malaise” or “poor performance” in racehorses, in a limited set of gastric ulcer samples. These findings have led to our hypothesis that equine herpesvirus infections could play a significant role in the development of the equine gastric ulcer syndrome (EGUS).

In order to test this, we propose two related, but independent aims in this 1-year proposal. In Aim 1, we will characterize the relationship between EHV-2/EHV-5 and the development of gastric ulcers in more detail by studying a large number of gastric tissue samples from race, research, and pleasure horses that are presented for necropsy at the New York State Animal Health Diagnostic Center (AHDC) for unrelated reasons. These samples will be thoroughly studied on a macroscopic (ulcer distribution and severity), microscopic (immunohistochemistry to detect EHV-2/-5 proteins) and molecular level (PCR to identify EHV-2/-5 DNA). In Aim 2, we explore the efficacy of antivirals and other drugs against equine gammaherpesviruses in vitro, using a combination of cytotoxicity assays, plaque assays and quantitative PCR analyses.