Cryptosporidium from tortoises: Genetic characterisation, phylogeny and zoonotic implications

Cryptosporidiosis is a disease caused by apicomplexan parasites of the genus Cryptosporidium, which affect the gastrointestinal tract of humans and animals worldwide. In the present study, Cryptosporidium isolates from captive European tortoises (Testudo graeca, Testudo hermanni and Testudo marginata) in Italy were genetically characterised using gene/s encoding Cryptosporidium oocyst wall protein (COWP) and/or the hypervariable segment internal to the SSU rDNA. Six isolates from T. graeca, T. hermanni and T. marginata revealed 100% sequence identity with the zoonotic Cryptosporidium pestis (Cryptosporidium parvum ‘bovine genotype’), while a sequence from one T. marginata was a unique uncharacterised genotype (Cryptosporidium sp. ex T. marginata). The new genotype is phylogenetically characterised as belonging to the intestinal cryptosporidial lineage. The present study indicates that tortoises may disseminate Cryptosporidium oocysts in the captive environment. The identification of the zoonotic genotype in the faeces of captive European tortoises indicates a potential risk for humans within the household.