C ase R e p o r t An Epizootic of Amoebiasis in a Mixed Species Collection of Juvenile Tortoises Simon Hollamby1, BVSc, David Murphy2, DVM, Chris A. Schiller3, DVM, DACVP 1. Department of Veterinary Anatomy and Pathology, The University of Queensland, 4072, Australia 2. Lowry Park Zoo, 7530 North Boulevard, Tampa, FL 33604-4754 Downloaded from http://meridian.allenpress.com/jhms/article-pdf/10/1/9/2206335/1529-9651_10_1_9.pdf by guest on 24 September 2021 3. All Creatures Pathology Service, 13633 North Cave Creek Road, Phoenix, AZ 85022 Abstr a c t: Over one year, 21 juvenile tortoises from four species died at a zoological park in Florida. The species were gopher tortoise, Gopherus polymerus\ West African spurred tortoise, Geochelone sulcata; ama- zonian yellow footed tortoise, Geochelone denticulata and the loggerhead musk turtle, Stemotherus m. minor. Histopathological examination revealed infection with an Entamoeba species. The clinical, pathological, treat­ ment protocols and epizootilogical features of the outbreak are presented. No difference in susceptibility to infection was found between the four species. Fecal flotations and direct microscopic examination of feces were ineffective in diagnosing the infection. Key words: Entamoeba invadens, gopher tortoise, Gopherus polyphemus, West African spurred tortoise, Geochelone sulcata, yellow footed tortoise, Geochelone denticulata, loggerhead musk turtle, Stemotherus m. minor, amoebiasis, parasitism. INTRODUCTION voirs of the organism (Frye, 1991). However, some authors state that the organism is highly pathogenic to all reptilian Entamoeba invadens is an amoebic protozoan with a direct species, including terrestrial chelonians (Greiner and life cycle associated with the ingestion of infected feces. The Schumacher, 1997). This case report documents an outbreak pathogenic stage of the life cycle involves a trophozoite form of amoebiasis in a zoological collection associated with high that principally affects the host’s intestinal tract, but may also mortality in three species of juvenile terrestrial, herbivorous be associated with pathology of the stomach, liver, spleen and tortoises and one aquatic, carnivorous turtle species. kidney (Barnard and Upton, 1994). Cysts containing one to Affected tortoises were housed in a main reptile service four vesicular nuclei are shed in the feces. These are the room (12 m X 3 m 3.5 m) containing other snake, lizard and infective stage of the life cycle (Keymer, 1981). While it is chelonian species. Glass fronted aquarium exhibits were generally agreed that Entamoeba invadens is highly patho­ embedded into the walls of, and serviced from this main genic in lizards and snakes, some reports suggest that the room. These exhibits contained the following specimens, dur­ organism is usually nonpathogenic in herbivorous chelonians, ing the time period in which the epizootic occurred (July and may even live in harmony as a commensal symbiont in 1997 to June 1998): turtles, tortoises and crocodilians, which act as healthy reser­ Volume 10, No. 1,2000 Journal of Herpetological Medicine and Surgery 9 Table 1. Specimens in exhibits in the reptile facility during epi­ teen 1996 hatchlings and ten 1997 hatchlings. The Hamilton tur­ zootic of amoebiasis. tle juveniles came from moats surrounding primate exhibits. The rest of the juvenile turtles were artificially incubated from eggs or SEX COMMON NAME SCIENTIFIC NAME reared from hatchlings found in various exhibits throughout the 1.1.0 Gray rat snake Elaphe obsoleta spiloides zoo. 2.0.0 Tokay gecko Gekko gecko Routine quarantine procedures for reptiles entering the collec­ 0.1.0 Southern copperhead Agkistrodon contortrix contirtrix tion included, but were not limited to, a minimum sixty day 0.1.0 Cottonmouth Agkistrodon piscivorous piscivorous quarantine period; two negative fecal flotations and direct saline 1.1.0 Timber ratdesnake Crotalus horridus wet mounts; and prophylactic antiparasiticides, including metron­ 0.0.3 Dusky pygmy rattlesnake Sistrurus miliarius barbouri idazole, 100 mg/kg once orally, then repeated at 2 and 4 weeks 1.1.0 Eastern diamondback Crotalus adamanteus (250 mg tablet, manufacturer unknown). At the time of this epi­ rattlesnake zootic, no dedicated reptile quarantine facility existed. Existing 1.2.0 Spotted turtle Clemmys guttata facilities were employed in such a manner as to prohibit physical contact, prevent disease transmission and avoid aerosol and 0.0.1 Stinkpot turtle Kinostemon odoratus drainage contamination. Standard practice was for reptiles within Drymarchon coralis couperi 1.0.0 Eastern indigo snake Downloaded from http://meridian.allenpress.com/jhms/article-pdf/10/1/9/2206335/1529-9651_10_1_9.pdf by guest on 24 September 2021 the collection to undergo fecal examination every three months. 0.1.0 Florida pine snake Pituophis melanoleucus mugitus All reptile species in the main reptile room were physically 0.0.2 American alligator Alligator mississippiensis separate from other species; however, due to the various modes of transmission all were at risk of infection with Entamoeba species. In addition, the following specimens were housed in the reptile The Amazonian river turtles were spatially the closest to the shelf service room on a temporary basis for periods during which the containing the juvenile tortoises (approximately 1.5 m distant), epizootic occurred: including the gopher tortoises. The iguana and the komodo drag­ on were the farthest removed. A sub-population of the room’s Table 2. Specimens housed on a temporary basis in the reptile occupants during the time of the outbreak, 8 Amazonian yellow facility during epizootic of amoebiasis. footed tortoises, 4 loggerhead musk turtles, and 23 West African spurred tortoises, Geochelone sulcata, were considered at higher SEX COMMON NAME SCIENTIFIC NAME risk because of their age or the spatial association of their tubs to 10.6.1 Yellow spotted river turtle Podocnemis unifilis that of the gopher tortoises. Subsequent to the gopher tortoise 0.0.5 Arrau turtles Podocnemis expansa deaths this subpopulation of the main reptile room was placed in 0.1.0 Komodo dragon Varanus komodensis a separate, designated quarantine room, adjoining the main reptile 1.0.0 Green basilisk Basiliscus plumifrons room. 1.1.0 Green iguana Iguana iguana CASE REPORT 1 All specimens were adult except the alligators. Except for the two Podocnemis species, which were kept in the same tub, each Nine gopher tortoise eggs were obtained from a wild-caught tub contained only one species. The P odocnem is species female, artificially incubated and hatched at the Lowry Park Zoo were housed in moats surrounding various zoo exhibits during the in Tampa, Florida in October 1996. The gopher tortoises were summer and in the reptile service room during the winter. kept in plastic tubs (Rubbermaid Incorporated, Wooster, OH) At one end of the reptile service room was a series of shelves measuring 53 cm x 38 cm at a stocking density of six animals per on which were placed adjacent plastic tubs (Rubbermaid tub. Newspaper substrate was changed daily. Newspapers came Incorporated, Wooster OH) containing the following chelonian from the same stack within the main reptile room. Used substrate species at the time of the first tortoise mortalities: was placed in the same garbage can also within the main reptile room. Tubs were cleaned daily with an approximately 80 mg/ml Table 3. Specimens housed adjacent to the gopher tortoises, solution of sodium hypochlorite (James Austin Company, Mars, Gopherus polyphemus, which first died of amoebiasis. PA). There was a double sink for cleaning all specimen equip­ ment for the entire room. Tubs were randomly allocated after cleaning amongst the population of mixed species juvenile tor­ NO COMMON NAME SCIENTIFIC NAME toises. The tubs were placed directly adjacent to one another. 34 West African spurred tortoise Geochelone sulcata Food comprised a 90% vegetable, 10% fruit mix with added com­ 8 Amazonian yellow footed tortoises Geochelone denticulata mercial vitamins and minerals (Reptical-Tetra Terrafauna, Morris 5 Loggerhead musk turtles Kinostemon m. minor Plains, New Jersey; Vionate-Gisbom-Rich Health, Atlanta, GA) 6 Gopher tortoises Gophems polyphemus that were prepared in a central kitchen region separate from the 29 Hamiltons pond turtles Geoclemys hamiltonii reptile facility. The same food supply and preparation facility 11 Florida box turtles Terrapene Carolina bauri were used for the entire zoo collection including the reptile col­ ill Spotted turtle Clemmys guttata lection. The tortoises were fed daily. Ambient temperature in the 6 Murray river turtles Emydura macquarii room was 25 - 27°C (78 - 79°F). Two reptile keepers were largely 2 Suwannee cooters Pseudemys concinna suwanniensis responsible for the maintenance and care of the species affected as described in this report as well as the rest of the reptile collec­ All were hatchlings or juveniles except the Suwanee cooters, tion. Three aquarists were also involved in a relief capacity. Pseudemys c. suwaniensis, which were an adult pair. The In October 1997, six of the juvenile tortoises, housed together Hamilton’s pond turtles, Geoclemys hamiltonii, comprised nine­ since birth, died over a 27 day period. The other three hatchlings 10 Journal of Herpetological Medicine and Surgery Volume 10, No. 1,2000 housed in a separate section of the zoo for the previous six floor space was approximately 1.5 m x 3 m. Cleaning and months showed no signs of illness. In the month