Pathology of upper respiratory tract disease of gopher tortoises in Florida

Between August 1993 and September 1995, 24 gopher tortoises (Gopherus polyp hemus) were received for pathological evaluations from various locations in Florida (USA). All tortoises were examined for clinical signs of upper res piratory tract disease (URTD) including nasal and ocular discharge, palpebr al edema, and conjunctivitis. Of the 24 tortoises, 10 had current or previo usly observed clinical signs of URTD and 14 did not. A bleed sample was dra wn for detection of anti mycoplasma antibodies by ELISA, and nasal lavage s amples were collected for culture and detection of Mycoplasma agassizii gen e sequences by polymerase chain reaction (PCR). Of the 14 clinically health y tortoises, eight were sero-, culture- and PCR-negative, and sis were sero positive for antibodies against M. agassizii. Of those six, five were cultu re- and/or PCR-positive for M. agassizii, and one was culture- and PCR-nega tive. OF the 10 ill tortoises, nine were seropositive by the ELISA and one was in the suspect range. Nine of the ill tortoises, including the suspect tortoise, were culture- and/or PCR-positive for M. agassizii, and one was c ulture- and PCR-negative. For histologic evaluation and discussion. the eig ht sero-, culture-, and PCR-negative tortoises were designated URTD-negativ e, and the other 16 were classified as URTD-positive. Histologic evaluation of the upper respiratory tract (URT) indicated the presence of mild to sev ere inflammatory, hyperplastic, or dysplastic changes in 14 URTD-positive t ortoises. Seven of eight URTD-negative tortoises had normal appearing nasal cavities; one had mild inflammatory changes. Transmission electron microsc opy revealed an organism consistent with Mycoplasma spp. on the nasal mucos al surface of tortoises with clinical signs and Lesions of URTD. Additional ly, Gram-negative bacteria were isolated more frequently from the nasal cav ities of URTD-positive tortoises than URTD-negative tortoises. Because clin ical signs of URTD were never observed in sir of the URTD-positive tortoise s, we also conclude that subclinical URTD can occur in gopher tortoises.