Andy C. Highfield
Tortoises and turtles, especially if recently imported or purchased, may have very large parasite burdens. It is essential in such cases that a thorough fecal examination be carried out to determine the nature and severity of the problem. Even isolated animals that have been maintained in captivity for years can acquire high concentrations of such parasites, though constant contamination of their habitat via fecal material, and subsequent ingestion of worm ova. Depending upon the class and life-cycle of the parasites involved, infection may also occur as a result of contaminated food items. Pathological and deleterious effects are not always obvious. Some nematodes can be seen with the naked eye, and almost all tortoise keepers will see some nematodes in the feces of their tortoises at some stage or other. Just because no 'worms' are visible, however, does not indicate that your tortoise is free of the problem. The only way to determine this is to have fecal samples regularly examined under the microscope. There are over 1,000 identified species of nematode that are known to affect reptiles. They vary in size from a few millimeters to over 30 cm. Most occur in the intestinal tract, though some can migrate into the lungs and throat, where the consequences can be very serious indeed. High concentrations of nematodes in the gut can also cause very severe health problems, even though the symptoms of such a condition may not be at all obvious to the keeper before serious damage results.
The only sensible course of action is to have periodic fecal exams carried out, and to treat the problem in the early stages, before high concentrations of the parasites build up.
One preparation often used with good results against many common nematodes is Panacur (fenbendazole). It is normally delivered as a liquid suspension, via stomach tube. A typical dosing regime is 50-100 mg per Kg, repeated in two weeks (Stein, 1996). In most cases, this mode of delivery is both safe and practicable. It is important to note, however, that Panacur is not effective against all classes or species of nematode parasite, and that only laboratory assay will determine if it is an appropriate drug to be used in the first place, or whether or not, following use, it has proved effective. With certain species of tortoise, however, delivering preparations by stomach tube can prove seriously problematic. Species such as Kinixys homeana and Kinixys erosa are especially difficult to handle, as they have a very narrow aperture between the carapace and plastron, are often extremely nervous, and can withdraw their heads back extensively with great strength - making handling potentially very traumatic and stressful. Other species where problems are often reported concrning oral administration include Leopard tortoises (Geochelone pardalis) and African Spurred tortoises (Geochelone sulcata). Both of these species are enormously strong, and have been know to resist the most expert and determined efforts to utilise a stomach tube.
In such situations, some veterinarians will recommend the use of an injectable antiparasitic such as Levamisole (Tramisol) or Ivermectin (Ivomec). The former, Levamisole, has been used in chelonians, but there are serious reservations as to its effectiveness. The latter, Ivermectin, has proved consistently fatal in chelonia and should not be used under any circumstances.
One possible alternative in these circumstances is to utilize the paste form of Panacur and deliver this orally, disguised on food. Clearly this will only be effective in the animal is still feeding, and there are undoubted problems in ensuring accuracy of dose. This is further complicated by the fact that the preparation is sold at different concentrations (strengths) in different countries. You should discuss this with your veterinarian, and calculate a suitable dose, based upon locally available products.
It is by no means a universal treatment or answer to the issue of nematode infestations in tortoises, but does provide a viable solution in many cases where the only apparent alternative may be to resort to anaesthesia, or where great stress and even injury can result as a consequence of the struggle necessary to administer the stomach tube.
Stein, G. (1996) In Reptile Medicine and Surgery (edited by Mader), W.B. Saunders and Company.
We would like to thank Chris Tabaka, DVM for pointing out serious typographical and other factual errors in the original version of this advice. We are indebted to him for his observations. It is unfortunate, however, that he did not do so sooner during the period when he served as Tortoise Trust veterinary adviser and was personally responsible for reviewing and ensuring the accuracy of all material placed on the website. The original, erroneous text remained on the site for a full two years during his tenure as our veterinary adviser.
It is our policy to immediately update and correct any errors that may occur on our site. We invite anyone who feels they have detected such errors to contact us with their comments, and we guarantee that in all cases where errors are bought to our attention corrective action will follow without delay.