Abstract/Introduction

Establishing normative data for free-ranging animals is essential in order to make judgements on the effects of human activities, effects of captivity and especially when contemplating translocations, restocking or introductions of animals. Fauna in Madagascar overall is under extreme pressure from human activity. Herpetofauna is undergoing onslaught from professional collectors for the international pet trade and equally important for food to Eastern markets. Rather than habitat degradation, many populations of reptiles are disappearing for entry into the human food chain.

In March of 1998 personnel representing the Reptile Department, the Field Veterinary Program, and the Wildlife Health Clinical Care Department of the WCS, worked at Cap Sainte Marie in southern Madagascar. The objective was to assess the health status of free-ranging radiated tortoises (Geochelone radiata) and to develop a normative data base for them.

Methods

Cap Sainte Marie is an area located at the southernmost tip of Madagascar. Over a 2-day period 36 free-ranging radiated tortoises underwent health evaluations. Blood was collected from brachial blood vessels and processed using routine field methodologies.² Nasal samples (n=15) were collected by flushing sterile water into each nostril and aspirating the residual fluid. Samples were placed into liquid nitrogen until being shipped on dry ice to the laboratory for mycoplasma PCR. Fresh feces from 13 animals were placed into tryptose-soy broth and frozen in liquid nitrogen for subsequent culture. Feces placed in formalin (n=11) were processed using routine techniques for parasite ova determination (Dr. Ellis Greiner, Dept. of Pathobiology, CVM, U FL, Gainesville, FL 32610 USA) and immunoflorescent antibody (IFA) testing (Anilab, Baltimore, MD 21228 USA ) for detection of Cryptosporidium spp. (n=11).

Plasma and nasal flush samples were stored at -70°C and fixed blood smears remained in Madagascar until a CITES permit could be obtained and transport back to the United States arranged. Subsequently, plasma was analyzed for biochemicals (IDEXX Veterinary Services Inc. One IDEXX Drive, Westbrook, ME 04092 USA), minerals (Animal Health Diagnostic Laboratory, P.O. Box 30076, Lansing, MI 48909 USA), and antibodies to Mycoplasma spp. via enzyme linked immunoassay (EIA) (Mycoplasma Research Lab, 1600 SW Archer Rd, Gainesville, FL 32610 USA), and antibodies to herpesvirus (EIA; Dr. Francesco Origgi, Dept. of SACS, CVM, U FL, Gainesville, FL 32610 USA).

Results

Hematology results are presented in Table 1. Hematocrit was only performed on five samples due to technical problems in the field and ranged from 20–24% (median=22.0) Total solids ranged from 2.2–4.6 g/dl (median=3.0). White blood cell counts were generally low, ranging from 296–8,712 cells/mm³ (median=1,760).

Plasma biochemicals and minerals are presented in Tables 1 and 2. Nasal flushes were all negative by PCR for Mycoplasma spp. The mycoplasma serologies were negative in 27/28 samples, with one being suspect. Herpesvirus EIA was positive in 3/6 (50%) tortoises.

Fecal analysis for parasites revealed pinworms in 11/11 (100%), Eimeria spp. in 2/11 (18%) and Caryspora sp. in 1/11 (9%) samples. IFA testing for Cryptosporidium sp. was positive for one of 11 (9%) samples. Bacterial culturing of feces was performed on 13 specimens. Two animals (15%) were positive for Salmonella sp. serovar kodjovi.

Table 1. Plasma biochemicals of free-ranging radiated tortoises (Geochelone radiata) (mean and range, n=14)

Table 2. Plasma mineral concentrations of free-ranging radiated tortoises (mean and range, n=13)

Discussion

Overall, the animals were in apparent good health. The hematologic and plasma biochemical data, when compared to published values for captive animals³ were clinically unremarkable. Uric acid levels in this population were higher than captive animals which may be a reflection of the xeric nature of the habitat in which the wild-caught animals were captured.

The finding of Eimeria spp. in 18% of the animals may be significant. Intranuclear coccidia has been identified as a pathogen sometimes causing death in several species of chelonia^1,2. It is possible that this protozoan may be the responsible organism. The finding of Cryptosporidium sp. is not unexpected and is consistent with findings in other free-ranging chelonians (unpublished data Raphael). The Salmonella serovar recovered from these animals is not known to be found in animals in the USA, and no serovars commonly found in captive animals in the USA were found in the free ranging animals.

Evidence of exposure to herpesvirus was unexpected as there were no signs of clinical disease on physical exam. The significance of this finding is unknown as there is limited information available on herpesvirus in free-ranging tortoises. The finding of one suspect positive mycoplasma serology sample with no positive PCRs and no clinically ill animals may indicate that the range of sensitivity of the test is not appropriate for this species or that the animal in question had very low titers to the organism.

The information gathered in this study should be considered baseline on a population that was relatively undisturbed by human perturbation. As such, it may be useful in future years as one prong for determination of the population health. The Cap Sainte Marie region is designated as protected, and there is presently a cooperative plan between WCS and Madagascar for establishing it as a National Park. Because of its remote location, the presence of government officers, and restricted access points it represents an opportunity to conserve and manage an intact patch of spiny desert and what appears to be extraordinary populations of radiated and spider tortoises, the landscape species of southern Madagascar.

Acknowledgments

The authors would like to recognize the efforts of Charles Walsh and Andrea Katz for their dedication and successful efforts in maintaining the Ivoloina Zoo; the Durable des Resources Forestieres of Madagascar for allowing this work to proceed; and to Dr. Pierre Pfister of the Institute Pasteur for his assistance with sample storage.

Literature Cited

1.  Garner, M.M., C. Gardiner, M. Linn, T.S. McNamara, B.L. Raphael, N.P. Lung, D. Kleinpeter, T.M. Norton, and E. Jacobson. 1998. Seven new cases of intranuclear coccidiosis in tortoises: an emerging disease? Proc. AAZV/AAWV: 71–73.

2.  Jacobson, E.R., J. Schumacher, and M. Greene. 1992. Field and clinical techniques for sampling and handling blood for hematologic and selected biochemical determinations in the desert tortoise, Xerobates agassizii. Copeia 1: 237–241.

3.  Marks, S.K., and S.B. Citino. 1990. Hematology and serum chemistry of the radiated tortoise (Testudo radiata). J. Zoo Wildl. Med. 21: 342–344.