PCR-RFLP analysis of the Cryptosporidium oocyst wall protein (COWP) gene discriminates between C. wrairi and C. parvum, and between C. parvum isolates of human and animal origin.

Cryptosporidium wrairi was isolated from guinea pigs during a spontaneous outbreak of cryptosporidiosis. Despite the morphological and antigenic similarities to C. parvum, C. wrairi displayed a different host range and site of infection and may represent a separate species or sub-species. We used the polymerase chain reaction to clone two distinct 550 bp-long DNA fragments, Wc-I and Wc-II, of the gene encoding the Cryptosporidium oocyst wall protein (COWP) of C. wrairi, which showed 98% identity to the C. parvum homologue. Within Wc-I, polymorphic Rsal restriction sites were used to develop a polymerase chain reaction-restriction fragment length polymorphism method able to distinguish C. wrairi from C. parvum and to identify two groups of C. parvum isolates differentially associated with animal and human infections.