First description of a Gammaherpesvirus in a common dolphin (Delphinus delphis) from the Eastern Mediterranean Sea

In September 2020, a male common dolphin (Delphinus delphis) was found dead on a beach near Bat-Yam, Israel. A small, raised, well circumscribed penile lesion (i.e., mass) was identified and removed for histology and molecular characterizations. By histology, the penile mass presented focal keratinization of the squamous epithelium and a mild ballooning of acanthocytes in lower epithelium levels, as well as features compatible with viral plaques, and tested positive for a gammaherpesvirus through molecular characterization analyses. Tissue samples from the lungs, liver, and spleen, however, tested negative for herpesvirus infection. The gammaherpesvirus detected herein is similar to other isolates found in several areas worldwide in different cetacean species. This is the first reported case of gammaherpesvirus infection in dolphins from the eastern Mediterranean Sea, indicative of the need for long-term assessments to create viral infections databases in cetaceans, especially in a climate change context, which is likely to intensify infectious disease outbreaks in marine mammals in the future.