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Treating Reptiles For Parasites

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My name is Danielle, and I work in a pet store. The question I wanted to ask was what kind of treatments you would recommend for reptiles that have just arrived, especially wild caught specimens? We deworm and de-mite them as soon as they come in with ivermectin oral medication, but my concern was also about protozoan bugs or things like coccidia/Giardia. What would you suggest as a precautionary treatment that would cover all the most common worms and infections?


My recommendation will always be to find a good herp vet who is willing to work with your store. This way, you will be able to contact your vet when new animals come in, and he or she can examine them, weigh them and then give you specific doses based on the types of herps your store has acquired.

Or better yet, you can collect fresh droppings from the new critters, and your vet can perform fecal parasite examinations to look for specific organisms that can cause problems. This would be the ideal situation, but I know that not all storeowners will permit such testing on all new herps (even if the tests are pooled). As an alternative, perhaps you can get a microscope (check pawn shops near universities and colleges to get a good deal on a used, but perfectly functional one), and learn how to read fecal flotations and smears. There are several good books that can help you. If you could ask your vet to help you get set up, then it could be the best possible compromise.

While I do think that ivermectin works well for external parasites, I don’t feel that it is the best choice for many internal parasites. Many anthelmentics (dewormers) must be very carefully dosed based on the precise weight of the herp, so if you plan to treat your animals without consulting with a herp vet, you must have a high-quality digital gram scale to measure the herp’s weight in grams, not ounces. Because of this, I choose to not give out specific doses.

Ivermectin (usually 10 percent cattle Ivomec) is used, mixed with propylene glycol for administration, as it doesn’t mix in water and just flocculates. This can be used to treat external parasites and many different types of internal parasites, including those sequestered in the tissues, and not inside the gastrointestinal tract. It can also be used as a spray for mites. It should not be used in chelonians, crocodilians, skinks or indigo snakes. Adverse reactions have occurred in chameleons, perhaps from larva dying and breaking down in the tissues. It cannot be given within 10 days of diazepam and tiletamine/zolazepam.


Metronidazole can be given for protozoan (flagellates, amoebae) overgrowth. Many protozoa are commensal or harmless unless in large numbers. It may cause seizures if overdosed. Oral tablets are horrible tasting.

Fenbendazole is the drug of choice for removing nematodes, and it may have an antiprotozoan effect. It can be given orally or percloacally in tortoises.

Praziquantel is used for removing cestodes and trematodes. It can be given orally or by injection.

Many sulfa drugs are used to treat coccidia, and all can cause problems in dehydrated animals or those with kidney problems.


Piperazine is an oral medication used to eliminate nematodes. Most medications should be repeated at certain intervals to assure removal of any larvae that have progressed to the adult stages in the intestinal tract. Also, for many parasites, it is best to rotate medications in case worms begin to develop resistance to a certain medication.

Paromomycin is used to remove amoeba and possibly cryptosporidium. It is not routinely used unless these organisms are diagnosed.

Pyrantel pamoate is a safe dewormer that is given orally. It is used to remove many types of nematodes.

Ronidazole is an excellent medication used to remove Giardia and other protozoa.


This is not, by any means, a comprehensive list of medications used in herps for parasite control and eradication. These are the more common ones. I hope this helps, and I hope your store manager and a local herp vet will be willing to work together with you to develop a plan for the reptiles in your store.

Margaret A. Wissman, DVM, DABVP has been an avian/exotic/herp animal veterinarian since 1981. She is a regular contributor to REPTILES magazine.

Need a Herp Vet?
If you are looking for a herp-knowledgeable veterinarian in your area, a good place to start is by checking the list of members on the Association of Reptilian and Amphibian Veterinarian (ARAV) web site at www.arav.com. Look for DVMs who appear to maintain actual veterinary offices that you could contact.