Benign Gastric Ulcer with Epstein-Barr Virus Infection Mimicking Malignant Gastric Ulcer

Epstein-Barr virus (EBV) is the cause of infectious mononucleosis, which is characterized by fever, lymphadenopathy, and sore throat. On the other hand, gastrointestinal symptoms of EBV infection like dyspepsia, abdominal pain are non-specific and rarely encountered, which means it is difficult to diagnose gastric involvement of EBV infection without suspicion. The relation between gastric carcinoma and gastric lymphoma associated with EBV infection is well defined, but relations with other EBV-associated gastrointestinal diseases such as gastritis and peptic ulcer disease have rarely been reported. We report a case of benign gastric ulcer with EBV infection confirmed by endoscopic and histological findings.

First demonstration of equid gammaherpesviruses within the gastric mucosal epithelium of horses

Horses commonly develop gastric mucosal ulcers, similar to humans, a condition known as equine gastric ulcer syndrome (EGUS) that can lead to poor performance and lost training time and care expenses. Unlike humans, however, an infectious bacterial cause of ulcers has not been conclusively identified. Herpesviruses, while well-established causative agents of diseases such as cold sores, genital lesions, and certain types of cancer, have also been implicated in the development of a subset of gastric ulcers in humans. The presence of equid herpesviruses in the gastrointestinal tract and their potential contribution to EGUS has not been evaluated. Here, we provide the first evidence of equid gammaherpesviruses 2 and 5 (EHV-2 and -5) within the epithelium of the gastric mucosa of horses. These viruses were initially detected by a nested PCR screen of gastric tissue samples obtained from client- and university-owned horses with and without ulcers; however, no association with EGUS was found in this limited sample set. We then validated a highly sensitive in situ hybridization (ISH) assay and used this assay to characterize the distribution of these viruses in necropsy gastric tissue samples from five racehorses. Analyses revealed frequent EHV-2 and EHV-5 co-infections within the gastric mucosal epithelium, regardless of the ulcer status. These results are the first to demonstrate the presence of equid gammaherpesviruses in the gastric mucosa of horses and warrants further investigation to determine the contribution of these viruses to the development of EGUS and/or other gastrointestinal diseases.