Cyclospora Cayetanensis Presence in the Environment—A Case Study in the Chicago Metropolitan Area

Abstract

Cyclospora cayetanensis is an emerging foodborne protozoan pathogen. Similar to other gastrointestinal illnesses, cyclosporiasis causes prolonged diarrhea. Unlike Cryptosporidium, Cyclospora oocysts are not infective when they are shed by infected individuals. Oocysts mature in the environment for 7–10 days before sporulating. Little is known about how C. cayetanensis is transported in the environment and which factors inhibit or promote sporulation. Water and fresh produce, such as leafy greens and berries, are common sources of infection. Contact with soil has also been correlated with Cyclospora infection. In addition to acting as a vector to transport oocysts from the environment to the body, water and soil may be important reservoirs to not only allow C. cayetanensis to persist, but also transport the oocysts from one location to another. This study examined a snapshot of an urban area near Chicago where human waste sporadically enters the environment via combined sewer outfalls (CSO). A total of 61 samples were collected from three CSO discharge events. Most of the 21 positive samples were wildlife feces (n = 13), and a few were soil (n = 7). There was one positive water sample. PCR analysis of soil, water, and wildlife feces indicated the presence of C. cayetanensis in the environment, suggesting likely transport of oocysts by wildlife. Given the emerging threat of cyclosporiasis, additional studies are needed to confirm and expand this case study.