Detection of Cyclospora cayetanensis in animal fecal isolates from Nepal using an FTA filter-base polymerase chain reaction method

Cyclospora cayetanensis is an emerging protozoan parasite capable of causing a protracted diarrheal illness in both immunocompromised and immunocompetent individuals. Ingestion of fresh produce and water sources contaminated with mature sporulated oocysts results in acquisition of cyclosporiasis. Currently, no animal model exists for the study of this pathogenic parasite and the only confirmed reservoir host for C. cayetanensis in nature is humans. Previously, Cyclospora-like oocysts had been detected by microscopy in several animals including non-human primates. However, their phylogenetic relationship to C. cayetanensis remained uncertain due to the limited availability of molecular techniques to differentiate and speciate these isolates. In the present study, we examined a series of fecal isolates obtained from dogs, chickens, and monkeys collected between May and September 2002 from several geographic regions of Nepal. All samples were examined by microscopy and a polymerase chain reaction (PCR) for the presence of C. cayetanensis. Both microscopic and conventional PCR/restriction fragment length polymorphism (RFLP) analysis demonstrated the presence of Cyclospora sp. in the fecal samples of two dogs, one chicken, and one monkey. Application of a species-specific multiplex PCR assay confirmed the presence of both Eimeria sp. and C. cayetanensis in the positive chicken sample and only C. cayetanensis in the dog and monkey samples. However, in the absence of tissue analysis, the assignment of these animals as a natural reservoir host for C. cayetanensis remains to be determined.