Cyclospora cayetanensis and cyclosporiasis: An update

Authors: ALMERIA, SONIA - US Department Of Health And Human Services (HHS); CINAR, HEDIYE - US Department Of Health And Human Services (HHS); Dubey, Jitender

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2019
Publication Date: 9/4/2019
Citation: Almeria, S., Cinar, H.N., Dubey, J.P. 2019. Cyclospora cayetanensis and cyclosporiasis: An update. Microorganisms. 7(9):317. https://doi.org/10.3390/microorganisms7090317.
DOI: https://doi.org/10.3390/microorganisms7090317

Interpretive Summary: Cyclospora cayetanensis is an emerging foodborne coccidian parasite of humans that thrives in conditions of poor sanitation and become increasingly recognized as a source of foodborne gastrointestinal disease in the United States. Progress in understanding this enigmatic parasite of evidently growing importance has been incremental, given the lack of cell culture or animal models to study the parasite, its capabilities, and its vulnerabilities. Here, USDA and FDA scientists endeavored to comprehensively review what has been learned about its epidemiology and diagnosis, in hopes of spurring progress in understanding the disease and limiting its public health impact and its cost to growers and grocers. The review will be of interest to epidemiologists, food safety authorities, parasitologists, pathologists, and physicians.

Technical Abstract: Cyclospora cayetanensis is a pathogenic coccidian parasite of humans, with a direct fecal-oral transmission cycle. It is globally distributed and an important cause of foodborne outbreaks of enteric disease in many developed countries, mostly associated with consumption of contaminated fresh produce. Because oocysts are excreted unsporulated and need to sporulate in the environment, direct person-to-person transmission is unlikely. Infection by C. cayetanensis is remarkably seasonal worldwide, although varies by geographical regions. The reasons for the apparent absence of symptomatic human infections for prolonged periods and where and how the parasite survives in the environment during those periods are unknown. Most susceptible populations are children, foreigners, and immunocompromised patients in endemic countries, while in industrialized countries, C. cayetanensis affects people of any age. The risk of infection in developed countries is associated with travel to endemic areas and domestic consumption of contaminated food, mainly fresh produce imported from endemic regions. Water and soil contaminated with fecal matter may act as a vehicle of transmission for C. cayetanensis infection. The disease is self-limiting in most immunocompetent patients, but it may present as a severe, protracted or chronic diarrhea in some cases, and may colonize extraintestinal organs in immunocompromised patients. Trimetoprim-sulfamethoxazole is the antibiotic of choice for the treatment of cyclosporiasis, but relapses may occur. There is a major bottleneck for research activities due to the absence of animal models and of in vitro cell culture. Detection of C. cayetanensis in produce represents a challenge. Recently, newly developed, highly sensitive, and specific molecular methods have facilitated clinical diagnosis and detection of oocysts in foods. Next generation sequencing technologies have proved a way to sequence nuclear and organellar genomes of C. cayetanensis, which will help in the development of methods for molecular typing and source tracking in outbreak investigations. Further research is needed to be conducted to understand many epidemiological aspects of this parasitic disease. Here, we summarize the biology, epidemiology, outbreaks, clinical symptoms, diagnosis, treatment, control and prevention of C. cayetanensis; additionally, we outline future research needs for this parasite.