CRF : TTN : ARCHIVES : INDEX

Turtle and Tortoise Newsletter, 2000, 4:14-16
© 2000 by Chelonian Research Foundation

Turtle and Tortoise Newsletter

Medical Issues Affecting the Rehabilitation of Asian Chelonians

Charles Innis, VMD
VCA Westboro Animal Hospital, 155 Turnpike Road, Westboro, MA 01581
E-mail: Clemmys@aol.com

Non-sustainable exploitation of many species of Asian turtles has been well publicized in recent years. Many species that were considered common only five to ten years ago have now been listed as threatened or endangered by the International Union for the Conservation of Nature (IUCN). While habitat loss and collection for the pet trade have had some impact on these species, it is generally agreed that the most significant factor affecting populations at this time is over-consumption by Asian food markets. Recently, an IUCN Asian Turtle Workshop was held in Fort Worth, Texas to address the possibility of maintaining groups of many of these species in captivity as a short-term, partial solution to this crisis. Healthy founder animals are of major importance to the establishment of captive collections.

Most Asian turtles that become available to western researchers have been originally collected via networks of local people. These well-established networks have developed over many years and result in the movement of turtles over hundreds to thousand of miles en route to food markets. During this time, the turtles are often very crowded and deprived of food and water. Western researchers or reptile dealers may acquire specimens at various points along this trade route. Clearly, prolonged transit under poor conditions results in declining health of most specimens, such that most reach the western world in poor health.

In the past, attempts to establish many of these specimens in captivity have failed. While lack of natural history information and variable stress response of certain species may be a factor, it is becoming clear that failure to seriously address health issues of specimens may be the most common reason for failure. While this article is not designed to be an all-encompassing treatise and formulary for rehabilitating turtles, it is hoped that the general concepts addressed herein will assist veterinarians and researchers in establishing specific treatment plans. It is this author’s opinion that most, if not all, Asian chelonians can benefit from veterinary examination and treatment as soon as possible after acquisition. Experience has shown that failure to promptly address medical issues often results in death of the specimen.

In general, newly acquired animals should be placed through a three to six month quarantine. During this time, the quarantined animals are isolated from established members of the collection while they are surveyed for the presence of contagious disease. Ideally, quarantine is carried out in a building separate from the healthy collection, or minimally, in a room separate from the healthy collection. All husbandry items including enclosures, water bowls, sponges, etc. from the quarantine room should not be mixed with the established collection; and waste from the quarantine room should not be disposed in proximity to the established collection. The quarantine room should be serviced after servicing the established collection. If new animals are to enter quarantine while animals nearing the end of quarantine are still present, subsets of quarantine (including new utensils, etc) should be established. Further recommendations for quarantine protocols are provided below.

Medical management of turtles must address environmental needs, nutritional support, and treatment of specific disease states. Obtaining as much natural history information as possible about the species of interest is necessary to provide a proper environment. For some species, this information is readily obtained, while for other poorly known species, this information may be unknown. In such cases, it may be necessary to provide the specimens with a range of environmental conditions to be modified based on the animals’ response.

In devising captive environments, important factors include choice of enclosure, temperature, substrate, humidity, photoperiod, visual security, and presentation of water. In general, environments and enclosures for initial medical care and quarantine should be able to confine the specimens, provide appropriate water, heat, light, and humidity, and should be easy to clean and disinfect. Elaborate, naturalistic vivaria should not be used during this time, as it is impossible to appropriately monitor the specimens and eradicate contagious pathogens in such conditions. Specimens should be housed individually during quarantine if space permits. In general, plastic, glass, acrylic, or fiberglass enclosures are most useful. For terrestrial species, enclosures can be simply lined with newspaper or paper towels. For aquatic and semiaquatic species, water may be added to the desired depth with no substrate used. In either situation, the substrate or water should be discarded and the enclosure should be washed and disinfected daily. Warm water and liquid dish soap may be used to wash the enclosure, followed by disinfection with a dilute bleach solution (20 parts water to one part bleach), quaternary ammonium compound, or chlorhexidene solution. Enclosures should then be thoroughly rinsed. It is generally not recommended to rely on filtration to clean water during quarantine as pathogens may survive within the filter medium. An exception may exist where ultraviolet sterilizers are used with filtration.

Items provided within the enclosure should be kept to a minimum and should be easy to clean and disinfect. Shallow plastic trays work best for providing food and water for tortoises and semiaquatic species. These must be shallow enough and located prominently enough for specimens to know that food and water are present, and to be able to easily access it. Overturned plastic containers such as plastic flowerpots cut in half best provide visual security. Animals can hide under these as well as bask on them. All enclosure furnishings should be washed and disinfected daily.

Temperature requirements vary somewhat among species; but, as a rule, most Asian species do well during quarantine in temperature ranges of 80-84oF. Some montane aquatic species such a Platysternon megacephalum prefer much cooler temperatures. This may also be true of some forest species such as Geomyda spengleri which seem most comfortable at 75-80oF. If temperature requirements are unknown, a range of temperatures should be provided. Simple incandescent lights in reflector fixtures may provide basking areas for species that bask, but many forest species will avoid bright light. In general, most Asian species prefer high humidity. The ambient humidity of the quarantine room may be kept generally high (60-80%) and substrates may be moistened or sprayed daily. The role of full-spectrum lighting in chelonian husbandry is poorly investigated, but such lighting may be useful with some species. In general, a daylength of twelve to fourteen hours is appropriate. Under no circumstances should lights be left on continuously. Failure to provide darkness may lead to physiological stress that exacerbates other medical problems.

The vast majority of Asian turtles entering the U.S. are in poor nutritional status. Having possibly been deprived of food and water for weeks to months, they are often dehydrated and depleted of fat and muscle tissue. Within the first hours to days of treatment, rehydration of the specimens is vital. In some cases, simply placing an aquatic turtle in water, or placing a terrestrial species in a shallow pan of water will lead to voluntary drinking. In more severely dehydrated patients, balanced electrolyte solutions may be given by the subcutaneous or intracoelomic route. In general, most chelonians can tolerate roughly 20cc of fluid per kilogram per day. In very severely ill specimens, intraosseus or intravenous fluids may be needed. The importance of rehydration in restoring circulating blood volume, electrolytes, organ function, and immune response cannot be overemphasized.

In rare cases, Asian chelonians will begin feeding voluntarily within the first two to three days of acquisition. If this occurs, nutritional recovery is made much easier. In general, initial food offerings should be simply intended to stimulate food intake without tremendous concern over the nutritional value of the food items. For example, brightly colored fruits and vegetables such as strawberries, melon, or yellow squash may often tempt Indotestudo species. Omnivores such as Pyxidea mouhouti and carnivores such as Platysternon may be tempted by earthworms. If regular feeding is established, a wider variety of items may be offered in an attempt to establish a long-term complete diet. It is unusual, however, for nutritional recovery to progress so smoothly.

Many new acquisitions will refuse to feed or may cease feeding after initially seeming enthusiastic. In the latter case, it is possible that food entering the debilitated body led to the proliferation of bacteria, fungi, or parasites, or placed metabolic stresses on poorly functioning liver and kidney tissue. As a result, nutritional support must be provided, and must often be combined with other medical therapy as discussed below. It is possible to produce the condition known as refeeding syndrome if too much nutrition is provided too rapidly. In this situation, the body that has been chronically deprived of nutrition becomes metabolically deranged when calories are suddenly provided. To prevent this, it is best to first work on rehydrating the animal and then gradually increasing its food intake over the first week of rehabilitation.

Nutritional support for chelonians is generally provided by tube feeding. In most cases this is accomplished by passing a feeding tube via the mouth down the esophagus to the stomach. This technique can be performed repeatedly and safely but requires training and patience to master. In some very large specimens, tube feeding may be so difficult that placement of a pharyngostomy tube is more practical. These surgically placed feeding tubes can be left in place for months and allow for delivery of food and medications. For most Asian species, daily tube feeding is recommended until consistent voluntary feeding is achieved. The volume of food that can be fed at any one feeding varies; but, as a generality, animals can handle about 10ml per kilogram at each feeding. It is important to choose a tube feeding product that will not clog the tube and that is appropriate for the species. For herbivores, pureed vegetables, vegetable baby food, or vegetable-based health food supplements may be used. For carnivores, enteral supplements for humans, dogs, or cats may be used, as well as pureed dog or cat food or meat baby foods. For omnivores, a mix of these products should be used. If the patient easily tolerates once daily feeding, attempt to feed two or three times daily. Advanced techniques for nutritional support such as parenteral nutrition are being investigated.

After establishing a plan for environmental conditions, rehydration, and nutritional support, an attempt should be made to diagnose and treat specific medical problems of the specimens. There are two ways to approach this phase of treatment. The first, which is often used when large numbers of common animals are to be rehabilitated simultaneously, is to use pre-existing knowledge of the common medical problems of the species to make assumptions about what treatments will be needed and then applying these treatments to the entire group. The second, which is often used when small numbers of rare individuals are involved, is to use various diagnostic tests to specifically define an individual’s medical condition such that treatment may be provided in a more specific manner. Each of these approaches to treatment has benefits and limitations. The group treatment approach has the benefit of being less expensive and more time- efficient as the animals can be treated in an “assembly-line” fashion. Its major limitation is that not all animals within the group will need all of the medications provided, and some may need medications that are not provided. Furthermore, when a good database of common disease problems is lacking for the species, as is the case with most Asian species, it is difficult to make correct assumptions about treatment. The more individualized approach has the benefit of tailoring a specific treatment to a specific disorder, but has the drawback of the expense that may be necessary to define the problem and the time needed to provide different treatments to different animals. It is probably best that some aspects of both approaches are combined for specific situations.

A variety of diagnostic tests exist to help diagnose specific problems in chelonians. While a complete discussion of diagnostic testing is beyond the scope of this article, an elementary understanding of the available tests is important. A veterinarian that is familiar with the species of interest should perform a thorough physical examination of the animal. In addition to the obvious external features, a thorough oral exam and coelomic palpation should be performed. Fecal testing to identify intestinal parasites should also be performed routinely. Such testing may involve fecal floatation, fecal cytology, fecal wet mounts, special staining techniques, or assays such as immunofluorescent antibody tests. Such tests often reveal the presence of parasites such as nematodes, flagellated protozoans, and amoebae. Addressing these parasites is of great importance in successful rehabilitation. Blood chemistry analysis and cell counts may also be useful diagnostic tests in some cases. Unfortunately, these tests lack sensitivity and it is very possible to have “normal” results in a very ill specimen. Radiography (x-ray) may be useful in diagnosing some conditions such as pneumonia, retained eggs, bladder stones, and bone lesions; but is limited in its usefulness in diagnosing other serious abnormalities such as liver or kidney pathology. Techniques for isolation or detection of specific microorganisms are very useful. These may include bacterial and fungal cultures, PCR testing, and antibody testing for chelonian pathogens such as Mycoplasma and herpes virus. Newer diagnostic tests such as ultrasound, MRI, CT scan, and endoscopy may be useful although availability may be limited and expense may be prohibitive. Of these, endoscopy offers tremendous value as it allows, for the first time, direct visualization and tissue biopsy through relatively non-invasive means. Endoscopy may allow the early diagnosis of specific abnormalities and allow more accurate prognoses to be provided.

Most Asian chelonians that arrive in the U.S. are suffering from a variety of bacterial and parasitic infections. Some may also have viral or fungal infections. Based on necropsy results of many Asian chelonians, bacterial infections are extremely common and often are the cause of death. Infections most commonly damage the digestive system, liver, kidneys, and lungs. It appears that as a result of long transit, dehydration, and malnutrition, the turtles become immunocompromised and are susceptible to colonization by normal enteric flora. As is true in most reptiles, gram negative bacteria such as Pseudomonas, Klebsiella, E. coli, etc. are most commonly isolated. However, gram positive bacteria such as Streptococcus and anaerobic bacteria such as Clostridium may also be involved. It is reasonable to assume that, in almost all cases, antibiotic use is of benefit in Asian turtle rehabilitation. Where specific pathogens can be isolated, antibiotic choice is based on sensitivity testing. Where cultures are not done, it is reasonable to choose a drug or combination of drugs to cover gram negative, gram positive, and anaerobic organisms. The most common drugs used by the author are cefotaxime, chloramphenicol, trimethoprim sulfa, piperacillin, enrofloxacin, amikacin, and metronidazole. The length of treatment generally varies from three to six weeks depending on the severity of infection. Caution should be exercised to monitor for opportunistic fungal infections and maldigestion as a result of elimination of normal intestinal bacteria. It is unclear whether probiotic agents may help to prevent this problem. Doses of drugs are not provided herein, but should be determined by a veterinarian that is current on pharmacology of chelonians. Adverse reactions, drug interactions, and overdoses may occur if drugs are not used under professional guidance.

The second major group of drugs that is almost always needed in Asian turtle rehabilitation is parasiticides. Common medications that may be used include fenbendazole for nematodes and metronidazole for some protozoans. Amoebae may be a major pathogen in some cases and may be difficult to eradicate completely. Combinations of drugs are often needed to treat amoebiasis and may include metronidazole, iodoquinol, chloroquine, diloxanide, and paromomycin. Trematodes have been found in tissues of several Asian species and may respond to treatment with praziquantel. Long-term treatment (months) may be necessary to eradicate parasites. At least three negative fecal results should be obtained before releasing an animal from quarantine.

A wide range of other treatments including antifungal drugs, nebulization, and gastroprotectants may be needed to successfully rehabilitate Asian turtles. Such treatments are still under investigation and cannot be fully endorsed at this time.

In many cases, Asian chelonians die despite excellent and appropriate treatment. It is critical that investigators utilize the tissues of dead specimens to increase our knowledge of the species. Failure to perform a necropsy, collect tissues for histopathology, provide tissues for chelonian genetics research, and offer the cadaver to a museum collection represents a major loss of valuable information. Those working with Asian turtles on a regular basis should establish a routine for dissemination of this information to colleagues. Only by thorough tissue analysis have diseases such as intranuclear coccidiosis of tortoises been discovered. More diseases await discovery, and only by identifying these diseases will we be able to refine our treatment plans to achieve greater success.