By Jennifer Coates, DVM
Lizard owners need a lot of information to take care of their pets successfully. If you don’t know the latest about the potentially fatal disease called cryptosporidiosis or crypto, you may be putting your lizards at risk.
What is Cryptosporidiosis?
Cryptosporidia are one-celled parasites (protozoa) that affect many different species of animals. It appears that the types of Cryptosporidia that affect lizards are unique to lizards. While they don’t make other animals (or people) sick, they can have devastating consequences for lizards.
A lizard that has Cryptosporidia in its intestinal tract sheds oocysts (microscopic eggs) in its feces. When other lizards come in contact with those oocysts and ingest them, they can become infected too. Some lizards will become very sick after infection, others show only mild symptoms, and some do not have any signs of illness at all.
The symptoms of cryptosporidiosis (the term used to describe the disease cause by Cryptosporidia parasites) are what you might expect from a disease that primarily affects the intestinal tract. They include:
- weight loss,
- poor appetite,
- and sometimes regurgitation.
Cryptosporidiosis is generally fatal about 50% of the time. Individuals who survive the infection can remain carriers and pass the parasite on to other lizards.
Diagnosing Crypto in Lizards
The symptoms of cryptosporidiosis are fairly nonspecific and can be seen with many other diseases. To start the diagnostic process, veterinarians will first collect a complete health history and perform a thorough physical examination on sick lizards. After this, if they believe that cryptosporidiosis is possibly to blame for a lizard’s symptoms, veterinarians will recommend specific tests to look for evidence of the parasite.
The simplest way to test for crypto is to examine a sample of feces under the microscope using a special flotation solution that concentrates Cryptosporidia oocysts. If they are seen, a diagnosis of cryptosporidiosis can be made. However, if no oocysts are visible, the disease cannot be ruled out because they are often shed intermittently and/or are present in low numbers.
More sensitive tests for crypto often need to be run. The best that are currently available are PCRs (polymerase chain reaction tests) that can be run on feces or swabs of a lizard’s cloaca. Unfortunately, false negative tests are still possible even with PCRs, and sometimes the only way to determine whether or not a lizard has crypto is to send samples of its intestinal tract to a pathologist after it has died or been euthanized.
Treating and Preventing Crypto in Lizards
As hard as cryptosporidiosis is to diagnose, it has proved even more difficult to treat. Veterinarians have tried numerous medications that successfully treat other protozoal diseases, but none have reliably eradicated crypto from lizards. That said, treatment with these medications (e.g., paromomycin or high doses of sulfa antibiotics) and general supportive care (nutritional therapy, stress reduction, etc.) will sometimes improve a lizard’s condition and prolong its life.
The problem with treating lizards who are severely affected by crypto is that they can present a grave risk to other lizards. The oocysts that are shed by sick lizards are extremely difficult to eradicate. They are resistant to most disinfectants (including bleach) and can survive for months in the environment.
If you decide to treat a lizard for crypto, make sure you do so in complete isolation from other lizards in your home. No items should move from the room where the lizard with crypto lives to any other room in the house. All potentially contaminated objects (vivarium, cleaning implements, etc.) should be thrown away when the infected lizard no longer needs them. Lizards with crypto often require treatment for the rest of their lives.
Preventing cryptosporidiosis from entering your home centers on avoiding the purchase or adoption of animals that have any symptoms of crypto. New arrivals should be quarantined and possibly even tested for crypto before they have any contact with other lizards. Talk to an experienced reptile veterinarian to determine what your best options for crypto prevention and/or treatment are given your particular circumstances.