Hookworms can infect turtles. From
turtle rescues...Parasites can be in the form of internal worms and protozoa or external ticks and mites.
Some indications that your turtle may be suffering from the effects of parasites could be lack of appetite, lethargy, diarrhea, undigested food in the stool, weight loss and in some cases they may even spit up food.
Some of the more common parasites found in turtles are pinworm, roundworm, and hookworm. If you see any indication of above symptoms get your turtle to a vet, or bring a fecal sample to be tested and have your turtle treated as necessary.
The more common treatments are with the drugs Fenbendazole (Panacur) & Metronidazole (Flagyl). Never, ever let your vet use Ivermectin to treat a parasite problem. That drug can be fatal to turtles. Also, if you own dogs, be very cautious about what de-wormer is used for them. Ivermectin is commonly used in Heartworm preventative medication. If your turtle has access to the area where your dog eliminates it may eat the stool of the dog and indirectly ingest the Ivermectin and can be fatal. I know of tortoise keepers this has happen to. For this reason our dogs are treated with Interceptor, which does not contain Ivermectin.
It’s extremely important to practice good hygiene when keeping turtles. Be sure to keep enclosure clean. Pick up any fecal matter daily and clean water and food dishes often. Wash your hands after handling any of your turtle’s equipment.
As described, keep a close eye on the stool and be prepared to collect any. The pet store should also foot the bill for any testing and/or treatment.