Cryptosporidiosis in reptiles

Cryptosporidiosis has been reported in a variety of different reptile species. This disease appears to be common in wild and captive reptile populations, and transmission occurs by the fecal-oral route. Infected reptiles may not show symptoms, but they are sporadic shedders of oocysts (eggs). The clinical signs of crypto infection include regurgitation and weight loss accompanied by abnormal enlargement of the mucous membrane layer of the stomach.

Diagnosing cryptosporidiosis can be challenging. One diagnostic method is the identification of oocysts within a stool sample by acid fast staining. A negative acid-fast stain only indicates that the reptile was not shedding at the time of sampling and does not mean that the animal is crypto-free. Standard practice is to run the test three times before assuming the animal is disease free. Endoscopy, which includes gastric lavage and biopsy, can also be used to identify this disease.

The most common species of cryptosporidiosis found in reptiles are C. serpentis, C. muris, and C. parvum. It has been suggested that the C. parvum (mouse-based) occysts found probably came from rodents ingested by reptiles rather than being an actual Crypto infection. This possibility of C. parvum infecting reptiles can only be completely ruled out by more careful biological and genetic studies.

In March 1999, the Saint Louis Zoo began a diagnostic and euthanasia program after the identification of chronic Cryptosporidium in snakes at its facility. To monitor the effectiveness of the control measures, samples of snakes were periodically taken over a period of one year. Immediately after the start of the control measure, 5 out of 10 and 8 out of 17 snake samples tested positive for Crypto in May and June 1999, respectively. Subsequently, only 1 of the 45 snake samples taken in five different time periods was positive for Cryptosporidiosis.

Currently there are no effective control strategies against Cryptosporidium in reptiles. In a small-scale study, snakes with clinical and subclinical Cryptosporidium were shown to be effectively treated (not cured) with hyperimmune bovine colostrum produced against C. parvum. Strict hygiene and quarantine of infected and exposed animals are mandatory for the control of cryptosporidiosis; however, most choose to euthanize the infected. The best method to prevent Crypto from spreading is to euthanize infected reptiles.

Cryptoocysts are only neutralized by exposure to moist heat between 113 ° F and 140 ° F for 5 to 9 minutes and by disinfection with ammonia (5%) or formal saline (10%) for 18 hours. Ineffective disinfectants included idophores (1% -4%), cresylic acid (2.5% and 5%), sodium hypochlorite (3%), benzalkonium chloride (5% and 10%), and sodium hydroxide (0, 02 m). Anything that may have potentially been in contact with an infected reptile should be thoroughly cleaned with an ammonia solution and allowed to dry for a period of at least 3 days.