Cryptosporidiosis has been reported in a variety of different reptile species. This disease appears to be common in wild and captive populations of reptiles, and transmission occurs by the fecal-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 layer of the stomach.
Diagnosis of Cryptosporidiosis can be challenging. One method of diagnosis is the identification of oocysts within a fecal specimen via 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 the animal is Crypto free. Standard practice is to test three times before assuming the animal is free from the disease. Endoscopy, including gastric lavage and biopsy, can also be utilized to identify this disease.
The most common species of Cryptosporidiosis found in reptiles is C. serpentis, C. muris and C. parvum. It has been suggested that C. parvum occysts (mouse based) found were probably from rodents ingested by the reptiles rather then and actual infection of Crypto. This possibility regarding C. parvum infecting reptiles can only be totally rules out by additional careful biologic and genetic studies.
In March 1999, the Saint Louis Zoo initiated a diagnosis-euthanasia program after the identification of chronic Cryptosporidium in snakes in their facility. To monitor the effectiveness of the control measures, samples were periodically taken from snakes for a period of one year. Right after the initiation of the control measure, 5 of 10 and 8 of 17 snakes samples were positive for Crypto in May and June of 1999, respectively. Afterwards, only 1 of 45 snake samples taken at five different time periods was positive for Cryptosporidiosis.
Currently there are no effective control strategies against Cryptosporidium in reptiles. In a small-scale study, it was demonstrated 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 are mandatory for control of Cryptosporidiosis, however most ellect euthanasia of the infected. The best method to prevent Crypto from spreading is to euthanize infected reptiles.
Crypto 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 could 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.
