Cryptosporidiosis has been found in over 40 species of snakes and is typically caused by Cryptosporidium serpentis. It is widely distributed in the United States and affects captive snakes more often than wild ones. The disease causes high morbidity and variable mortality. The most typical pathologic change is an enormous thickening of the stomach wall, which prevents passage of normal prey items. Clinical signs include regurgitation of undigested prey 1 to 3 days after feeding, diarrhea, visible bulging in the gastric region, weight loss, and lethargy. Disease progression is slow and leads to death. Subclinical infections can exist with varying periods of oocyst shedding. Clinically affected snakes intermittently shed large numbers of oocysts in the feces. Sporulated oocysts can survive for up to 3 months at temperatures of 25° to 30°C, are resistant to many disinfectants, and remain viable after routine chlorination of water. Several methods for detecting Cryptosporidium exist, the most definitive being postmortem histologic examination of gastric tissue. Gastric lavage is a good way to detect subclinical infections. Several treatments have been evaluated in affected snakes, the most promising being hyperimmune bovine colostrum therapy, although clinically ill snakes were not cured with this method. Prevention and control methods should include screening for Cryptosporidium to avoid introduction into collections, quarantine periods, and possibly submitting prey items to a freeze-thaw cycle before feeding, although the role of prey in transmission remains debatable. No reports of C serpentis in humans currently exist, but its occurrence in immunocompromised patients cannot be ruled out.

COMMENTARY: While causes of regurgitation such as other infectious pathogens, mismanagement, cancer, acute stress, and liver or kidney failure might be involved, cryptosporidiosis should be included on the differential list. Diagnosis can prove tricky, but gastric lavage appears to be a reasonable method. The procedure is described in some detail here. A truly effective treatment remains to be found, making prevention and control all the more important. As such, the authors discuss several considerations for prevention and control as well as potential zoonotic aspects.

Cryptosporidiosis in snakes. Hellebuyck T, Vancraeynest D, Geurden T, et al. FLEMISH VET J 76:26-30, 2007.