27th Annual Meeting and Symposium of the
Desert Tortoise Council, March 22-24, 2002
Abstracts

Serological and Molecular Evidences of Herpesvirus Exposure in Desert Tortoises from the Mojave Desert of California

Francesco Origgi, DVM, Ph.D.¹, C. H. Romero², Paul Klein3, Kristin Berry⁴, and Elliot Jacobson^5
1Human Virology Unit, Department of Infectious Diseases and Immunology, San Raffaele Scientific Institute (Dibit), Milano, Italy; 
²Department of Pathology, University of Florida; 
³Department of Pathology, Immunology and Laboratory Medicine, University of Florida;
⁴U.S. Geological Survey, Western Ecological Research Center, Riverside, CA; 
⁵Department of Small Animal Clinical Sciences, University of Florida

Herpesvirus has been associated with a disease in several species of tortoises characterized by stomatitis-rhinitis. Although most of the tortoise herpesvirus literature involves Mediterranean tortoises (Testudo graeca and T. hermanni), the occurrence of herpesvirus infection has been reported in three captive desert tortoises (Gopherus agassizii). Herpesvirus infection was identified upon post-mortem evaluation of these animals.

Because of a lack of epidemiological data about the prevalence of tortoise herpesvirus in captive and free ranging desert tortoises, we tested a total of 415 plasma samples collected from captive and free ranging desert tortoises from in and around Fort Irwin (Barstow, CA). The serological test used was an enzyme linked immunosorbent assay (ELISA) recently validated for Mediterranean tortoises. One hundred and ten samples (26.5%) were positive for exposure to tortoise herpesvirus. The serological test was complemented by a polymerase chain reaction (PCR) recently developed, that confirmed the presence of herpesviral DNA in two of six tissue samples obtained from wild desert tortoises. The sequencing of the amplified fragments is currently ongoing.

Several of the desert tortoises ELISA positive for herpesvirus exposure were known to be also positive for mycoplasma exposure. While Mycoplasma agassizii has been shown to be a serious pathogen for desert tortoises, the role of tortoise herpesvirus is still not clear. However, the results presented indicate that herpesvirus may operate as an important pathogen in wild populations of desert tortoises.