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

Causes of Mortality and Diseases in Tortoises: A Review

Elliot R. Jacobson
College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610-0126

Most of the 40 species of tortoises are experiencing populations declines. Of the various causes of mortality in wild populations of tortoises, the interactions of disease and population dynamics are least understood. While habitat degradation is considered the most significant threat to wild populations of tortoises, disease is being observed more frequently in certain populations. An upper respiratory tract disease has been seen in populations of desert tortoise, Gopherus agassizii, in the Mojave Desert, USA and certain populations of the gopher tortoise, Gopherus polyphemus, in Florida, USA. In both species, Mycoplasma agassizii has surfaced as the causative agent. Compared to wild tortoises, much more information is available on diseases of captive tortoises. Of infectious diseases, viral, bacterial, mycotic and parasitic diseases have all been reported. Herpesvirus has been incriminated as the causative agent of stomatitis, glossitis, conjuctivitis, and rhinitis is in the European tortoises, Testudo graeca and T. hermanni. An intranuclear coccidial protozoan has been associated in deaths of several species of exotic tortoises imported into the United States. Noninfectious diseases identified in tortoises include various nutritional diseases, hypothyroidism, and neoplasia. Virtually nothing is known about the effects of pollutants/toxicants in individual or populations of tortoises.