Cryptosporidiosis in Reptiles


Cryptosporidiosis has been reported in various species of reptiles. This disease appears to be common in both wild and captive reptile populations, and transmission occurs via the faecal-oral route. Infected reptiles may not express symptoms but are sporadic shedders of oocysts (eggs). Clinical signs of Crypto infection include regurgitation and weight loss accompanied by abnormal enlargement of the mucous membrane of the stomach.

Diagnosis of cryptosporidiosis can be difficult. One diagnostic method is the identification of oocysts in a fecal sample by acid-fast staining. A negative acid fast staining only indicates that the reptile was not shedding at the time of sampling and does not mean that the animal is crypto-free. Common practice is to test three times before assuming the animal is disease free. Endoscopy, including gastric lavage and biopsy, can also be used to identify this disease.

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

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

There is currently no effective control strategy against Cryptosporidium in reptiles. In a small-scale study, it was shown that snakes with clinical and subclinical Cryptosporidium could be effectively treated (not cured) with hyperimmune bovine colostrum raised against C. parvum. Strict hygiene and quarantine of infected and exposed animals is mandatory for the control of cryptosporidiosis, but most of the infected are euthanized. The best method to stop Crypto from spreading is to euthanize infected reptiles.

Cryptographic oocysts 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 come in contact with an infected reptile should be thoroughly cleaned with an ammonia solution and allowed to dry for at least 3 days.

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