Epidemiology
More than 1400 laboratory-confirmed cases of cyclosporiasis were reported to the U.S. CDC in each of 2018, 2019, and 2020, reflecting an increase in cyclosporiasis incidence since 2015 [PMID:37466070].
Epidemiological investigations face challenges due to an incubation period up to 2 weeks and intermittent symptom patterns, complicating traceback investigations because patients often cannot recall specific produce items consumed weeks prior [PMID:37466070].
The study by Barratt et al. (PMID:34511150) demonstrates that the enhanced CDC genotyping system, utilizing deep amplicon sequencing and machine learning, maintains excellent sensitivity (90%) and specificity (99%) in identifying outbreak clusters, crucial for epidemiologic investigations.
An ensemble of similarity-based classification algorithms effectively grouped genetically heterogeneous Cyclospora cayetanensis infections into clusters, correlating with epidemiological outbreak linkages [PMID:31148531].
Detection of both sporulated and unsporulated Cyclospora oocysts in tap water and lettuce supports their role as transmission vectors [PMID:10605507].
Clinical Presentation
Cyclosporiasis infections result in a range of nonspecific symptoms including watery diarrhea, loss of appetite, cramps, and bloating [PMID:37466070].
Among 150 immunocompromised patients, Cyclospora was detected in 4% of cases, highlighting its prevalence in this population [PMID:10605507].
Diagnosis
Barratt et al. (PMID:34511150) highlight that the improved genotyping system effectively distinguishes between epidemiologically-defined clusters and genetic clusters, supporting its utility in diagnostic and outbreak management contexts.
The Bayesian and heuristic classification approach used in genotyping C. cayetanensis infections enhances the ability to discern complex genetic relationships, aiding in more accurate diagnosis and outbreak management [PMID:31148531].
Cyclospora oocysts resist staining while Cryptosporidium oocysts take up pink coloration using the modified detergent ZN stain, facilitating accurate differentiation [PMID:10605507].
Management
The robust performance of the CDC's enhanced genotyping system, as evaluated in 2019 outbreaks (PMID:34511150), underscores its potential to aid in targeted public health interventions and outbreak containment strategies for cyclosporiasis.
Key Recommendations
Given the significant correlation between genetic clustering and epidemiological data, integrating advanced genotyping methods is recommended to improve trace-back investigations of cyclosporiasis cases [PMID:31148531]. (Evidence: Expert opinion)
References
1 Ahart L, Jacobson D, Rice M, Richins T, Peterson A, Zheng Y et al.. Retrospective evaluation of an integrated molecular-epidemiological approach to cyclosporiasis outbreak investigations - United States, 2021. Epidemiology and infection 2023. link 2 Barratt J, Houghton K, Richins T, Straily A, Threlkel R, Bera B et al.. Investigation of US Cyclospora cayetanensis outbreaks in 2019 and evaluation of an improved Cyclospora genotyping system against 2019 cyclosporiasis outbreak clusters. Epidemiology and infection 2021. link 3 Barratt JLN, Park S, Nascimento FS, Hofstetter J, Plucinski M, Casillas S et al.. Genotyping genetically heterogeneous Cyclospora cayetanensis infections to complement epidemiological case linkage. Parasitology 2019. link 4 Abou el Naga IF. Studies on a newly emerging protozoal pathogen: Cyclospora cayetanensis. Journal of the Egyptian Society of Parasitology 1999. link