Incidental Detection of Cyclospora Cayetanensis during General Health Screening: A Case Study from Singapore

Background: Cyclospora cayetanensis is a coccidian parasite recently recognized and characterized that cause enteritic infection worldwide. Endemic in tropical and subtropical countries where asymptomatic carriage is common, this parasite is also frequently associated with foodborne and waterborne outbreaks and reported from travellers in industrialized countries. Poorly characterized by routine laboratory procedures, the oocysts of C.cayetanensis are also discontinuously shed, altogether making this parasite difficult to detect. In Singapore information about C.cayetanensis are scarce and the endemicity status is unknown, while the country seems vulnerable to outbreak occurrence. Case study: The present report describes the incidental laboratory finding of C.cayetanensis oocysts in the stool of an asymptomatic immunocompetent patient attending a general health screening. Initial suspicion about the diagnosis was confirmed by several morphological methods and concurrently by amplification and sequencing of the parasite DNA. Along the study, co-infections with Blastocytis sp. ST3, Cryptosporidium parvum/hominis and the nonpathogenic Entamoeba hartmanni were noticed and confirmed by molecular methods. Conclusions: This report could serve to raise awareness about Cyclospora cayetanensis and the asymsptomatic carriage of enteritic protozoa, and as a reminder about the risk of cyclosporiasis especially in the most susceptible populations such as: children, elderly and immunocompromised.