Pet Education Reptiles
Pet Education Reptiles Pet Education Reptiles Pet Education Reptiles
Free Shipping on orders over $49
Common Internal Parasites in Turtles and Tortoises
Veterinary & Aquatic Services Department, Drs. Foster & Smith
Turtles - Tortoises & Terrapins
Print Article | Email Article
Bookmark and Share
Click here for a pdf version of this article.  See related products at Pet Supplies
Turtles and tortoises are fortunate that they are not as susceptible to as many varieties of parasites that most mammals, birds, and other reptiles are plagued with. However, there are several internal and external parasites that can cause severe problems and even death, if they are not properly treated. Most parasitic problems in turtles and tortoises occur when the animals are either kept in close captivity with other turtles or tortoises, or when kept in unsanitary housing conditions.

Turtles and tortoises should NEVER be treated with ivermectin.

One important note when it comes to treating turtles and tortoises concerns the use of the antiparasitic drug ivermectin. While ivermectin is one of the most effective antiparasitic drugs in the world, it should never be used on turtles or tortoises. It can be extremely toxic and cause death, if administered to turtles or tortoises. If there is any question as to the safety of an antiparasitic drug in turtles and tortoises, a qualified veterinarian should be consulted.


Nematodes are one of the most common parasites found in turtles and tortoises. These internal parasites are similar to the common roundworms that infect most mammalian species. The infection occurs when a healthy turtle ingests the tiny roundworm eggs that have been deposited in the environment through infected turtles feces. The eggs hatch, the larvae mature, and the worms set up residence in the digestive tract and will continue to reproduce and grow. Turtles and tortoises with a heavy worm load will often have symptoms of weight loss, diarrhea, and possibly vomiting of worms.

Diagnosis is either made by seeing the worms in the feces or vomitus, or more commonly, through a fecal sample examined under a microscope. Treatment is best achieved with the oral administration of the antiparasitic drug fenbendazole. Your veterinarian will be able to prescribe this medication and calculate the proper dose according to the weight of the animal.

Tapeworms and flukes

Tapeworms and flukes can infect aquatic turtles, but are rare in tortoises. These parasites need to go through an intermediate host and are not much of a problem in most well-cared-for captive turtles. If the small worms are seen in the feces or diagnosed through a fecal exam, they can be successfully treated with praziquantel. Again, your veterinarian will be able to prescribe this medication and calculate the proper dose according to the weight of the animal.

Flagellate organisms

Flagellate organisms are present in many healthy tortoises and turtles, however, if they are present in high numbers, they can cause severe intestinal problems. Flagellates are protozoans with the most common genus being Trichomonas. These microscopic motile, whip-like organisms live in the intestinal tract and can be easily identified through a microscopic fecal exam. Severe infestations of Trichomonas can lead to diarrhea, dehydration, weight loss, and the passage of undigested food. The presence of these organisms in the feces does not always indicate an infection, and the veterinarian needs to determine if they are actually causing a problem before initiating treatment. The common drug used for treatment is metronidazole. While metronidazole is an effective drug, caution must be used to avoid killing off all of the good organisms in the intestinal tract resulting in a sterile intestine. Feeding yogurt, or in more severe cases, the feces from a healthy tortoise, may be necessary to re-seed the intestine after metronidazole treatment.

Dietary deficiencies or excesses, such as an excessive intake of high sugar-fruit, are often a common cause of increased levels of flagellate organisms. Diets that are too low in dietary fiber can also be a cause. Keeping tortoises of different species together in the same enclosure or overcrowding is another factor, which significantly increases their likelihood of developing problems with flagellate organisms. Another cause of outbreaks in tortoises is associated with excessively high overnight temperatures or unrestricted access to heat lamps. Tortoises that are fed a natural diet and those that are allowed to graze under more natural conditions rarely develop flagellate problems. Allowing tortoises an appropriate cooling period at night will often greatly diminish their risk of developing a problem with trichomonas.


This is just a small listing of some of the common parasites that can infect turtles and tortoises. Good housing, proper nutrition, and regular physical exams including fecal checks can go a long way in preventing parasitic problems. If you suspect that your turtle or tortoise is harboring a parasite, contact your veterinarian immediately.

References and Further Reading

Highfield, A.C. Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles. Carapace Press, London; 1996.

Jenkins, J. The Veterinary Clinics of North America Exotic Animal Practice. W.B. Saunders Co. Philadelphia, PA; 1999. 

Click here for a pdf version of this article.  See related products at Pet Supplies  
Print Article | Email Article
TetraFauna ReptoMin Floating Food Sticks
TetraFauna ReptoMin Floating Food Sticks
As low as $7.19
Zoo Med Sun-Dried Red Shrimp
Zoo Med Sun-Dried Red Shrimp
As low as $5.59
Zoo Med Tortoise Block Calcium Block with Cactus & Vegetables
Zoo Med Tortoise Block Calcium Block with Cactus & Vegetables
As low as $3.99
Zoo Med Can O' Foods
Zoo Med Can O' Foods
As low as $3.19

Facebook YouTube Blog Connect with us

Subscribe to email newsletters:
featuring helpful articles, tips and online only product specials from Drs. Foster & Smith. Learn more here !

About Us Article Reprints Awards & Memberships Request a FREE Catalog Tell a Friend
Meet Our Staff Terms & Use Site Map Free Newsletters Links to Us
Visit our other websites: Doctors Foster and Smith Pet Supplies - Quality Aquatic Life Direct to Your Door
For product information, call 1-800-826-7206

Copyright © 1997-2016, Petco Wellness, LLC. All rights reserved.
2253 Air Park Road, P.O. Box 100, Rhinelander, Wisconsin, 54501.
Terms of Use | Privacy Policy | Your CA Privacy Rights | Copyright Claims | Pet Medical Records Policy