Fatal Lymphoproliferative Disease Associated with a Novel Gammaherpesvirus in a Captive Population of Common Marmosets

Background and Purpose: Callitrichids (marmosets and tamarins) are extremely susceptible to experimental tumor induction by herpesviruses native to other primate species. A colony of common marmosets developed a syndrome of weight loss, inappetence, diarrhea, and in several animals, palpable abdominal masses. Methods: Marmosets in the colony were subjected to histologic examination and serologic testing for EpsteinBarr virus (EBV). The DNA from tumors that developed in the marmosets was subjected to consensus primer polymerase chain reaction (PCR) analysis designed to amplify conserved regions of herpesvirus genomes. Results: The mesenteric lymph nodes and intestinal mucosa were consistently infiltrated by principally B lymphocytes, which often obliterated the normal architecture. Of 84 clinically normal marmosets, 52 were seropositive for EBV. The tumor DNA contained previously unreported herpesvirus sequences closely related to but distinct from those of EBV, Herpesvirus papio, and these lymphocryptovirus, a novel gammaherpesvirus. Results of PCR analysis of circulating lymphocytes from EBV-positive, clinically normal marmosets were negative for EBV antibodies and were positive for marmoset lymphocryptovirus; PCR analysis of circulating lymphocytes from EBVnegative marmosets yielded negative results for EBV and this novel marmoset lymphocryptovirus. Conclusion: This novel gammaherpesvirus possibly associated with tumor development may have important management implications for captive callitrichids.