25th Annual Meeting and Symposium of the
Desert Tortoise Council, April 21-24, 2000
Abstracts

Effects of Upper Respiratory Tract Disease On Gopher Tortoise Populations

Joan E. Diemer Berish
Florida Fish and Wildlife Conservation Commission, 4005 South Main Street Gainesville, FL 32601

Within the last decade, research has revealed an upper respiratory tract disease (URTD) in wild gopher tortoises (Gopherus polyphemus) in Florida. One causal agent of URTD is Mycoplasma agassizii. A blood test has been developed to detect antibodies to M. agassizii. Blood samples collected at various Florida sites have indicated exposed gopher tortoise populations in 24 of Florida's 67 counties. In 1998, the Florida Fish and Wildlife Conservation Commission initiated a radiotelemetry study to investigate the effects of URTD on tortoise populations on public lands. A total of 61 tortoises were radio-instrumented on 3 URTD study sites and a control site. Because the current blood test only indicates exposure to mycoplasma, nasal lavages were also taken to detect presence of mycoplasma. A different mycoplasma was detected on each of the 3 URTD study sites: Mycoplasma agassizii on Gold Head Branch State Park, a genetically distinct mycoplasma on Cecil Field Naval Air Station, and an undescribed mycoplasma on Oldenburg Mitigation Park. No seropositive or diseased tortoises have been found to date on the control site. Recapture efforts in 1999 revealed that 2 of 15 radioed tortoises at Oldenburg had died outside their burrows. A third, severely symptomatic tortoise was euthanized, necropsied, and found to have nasal lesions associated with mycoplasma infection. Over 120 dead gopher tortoises were found at Oldenburg during 1998-1999. One of 15 radioed tortoises at Cecil Field was found dead in its burrow. Continued monitoring will document mortality rates and changes in serology over time.