Cryptosporidiosis caused by two distinct species in Russian tortoises and a pancake tortoise

Abstract

Cryptosporidiosis in squamates is well documented, but there is very limited information available on cryptosporidiosis in testudines. We describe three cases of cryptosporidiosis in tortoises with associated pathology. Two Russian tortoises (Agrionemys [Testudo] horsfieldii) and a pancake tortoise (Malacochersus tornieri), all from separate collections, were found dead. At necropsy, two had histological evidence of intestinal cryptosporidiosis and one had gastric cryptosporidiosis. Consensus Cryptosporidium sp. PCR and sequencing was used to identify the Cryptosporidium sp. present in these three tortoises. In the juvenile Russian tortoise with gastric cryptosporidiosis, the organism had 98% homology with a previously reported sequence from an Indian star tortoise isolate. A second chelonian Cryptosporidium sp. was identified in the pancake tortoise and the second Russian tortoise. This sequence was 100% identical to a shorter gene sequence previously reported in a marginated tortoise. This is the first report coordinating pathology with Cryptosporidium characterization in chelonians. The two Cryptosporidium sp. found in tortoises segregate according to site of infection, and there may be further differences in pathology, host range, and transmission. These Cryptosporidium sp. appear to be able to infect diverse tortoise host species. This may be an under-recognized problem in tortoises.