A novel gammaherpesvirus found in oral squamous cell carcinomas in sun bears (Helarctos malayanus).

A novel herpesvirus was detected in sun bears (Helarctos malayanus) with oral squamous cell carcinoma. Five captive sun bears from 4 institutions in the United States presented with oral lesions ranging from erythema and mild erosions to nodular, ulcerated masses. All 5 were diagnosed with squamous cell carcinoma. The tumors were treated with surgical resection but recurrence, local extension, or appearance of new lesions was noted in all cases. Intralesional chemotherapy was administered in 2 cases, and the nonsteroidal anti-inflammatory drug piroxicam was administered in 3 cases. Virus was detected in 4 of the 5 bears' tissue samples using a consensus herpesvirus polymerase chain reaction. Nucleotide sequencing and phylogenetic analysis showed that this herpesvirus is in the subfamily Gammaherpesvirinae and distinct from other known herpesviruses. The association between the herpesvirus and squamous cell carcinoma is unknown. The current study presents a novel gammaherpesvirus within the order Ursidae, with the name Ursid herpesvirus 1 proposed.