Cyclospora cayetanensis
Junqiang Li ,1,2
Kaihui Zhang ,1,2
and Longxian Zhang 1,2,
*
1
College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
2
International Joint Research Laboratory for Zoonotic Diseases of Henan, Zhengzhou 450046, China
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Cyclospora cayetanensis is a coccidian parasite that causes gastrointestinal symptoms only in humans.
International travel and food importation from cyclosporiasis-endemic regions are linked to cyclosporiasis
outbreaks, making it not only a burden on individual health but also a global public threat. Human cyclosporiasis
has been identified in at least 54 countries, with the disease being most common in low-income developing
countries. It is transmitted via the fecal–oral route and has both asexual and sexual development stages.
Asexual multiplication results in schizonts and merozoites. In the sexual stage, the male parasite (microgamete)
fertilizes the female (macrogamont), leading to the development of a zygote. The unsporulated oocysts are
excreted in the host feces. Detection in transmission vehicles, such as produce, water, or soil, is useful for
tracing the source of cyclosporiasis. Knowledge of pathogenicity and immune responses are urgently needed
to expand the treatment options.
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KEY FACTS:
Humans are the only known host of
C. cayetanensis. Many outbreaks are
related to transregional travel and
worldwide food supply, making it a
global public health concern.
The oocysts need to mature (sporulate)
in the environment before becoming
infectious. Infections have a marked
seasonal distribution, with the majority
occurring during the rainy season or
summer.
Molecular genotyping based on
sequence polymorphisms will be helpful
in differentiating case clusters to assist in
trace-back investigation.
Effective culture techniques and animal
models are not yet available, so there is
poor understanding of the biology and
pathogenesis of C. cayetanensis.
DISEASE FACTS:
Cyclosporosis is most prevalent among
children in endemic areas. Symptoms
include persistent diarrhea and wasting,
although infections in immunocompetent
individuals may be asymptomatic.
Infection causes villous atrophy, crypt
hyperplasia, and lymphocytic infiltration
of the host small intestine, leading to
malabsorption and sometimes with
biliary involvement.
Although no vaccine is available, early
detection and treatment may result in a
favorable clinical outcome.
Treatment with cotrimoxazole is usually
successful. Ciprofloxacin is an alternative
option for patients with sulfonamide
intolerance.
TAXONOMY AND CLASSIFICATION:
PHYLUM: Apicomplexa
CLASS: Conoidasida
ORDER: Eucoccidiorida
FAMILY: Eimeriidae
GENUS: Cyclospora
SPECIES: C. cayetanensis
*Correspondence:
zhanglx8999@henau.edu.cn (L. Zhang).
Trends in Parasitology, May 2022, Vol. 38, No. 5 © 2021 Published by Elsevier Ltd. https://doi.org/10.1016/j.pt.2021.11.003 419
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Acknowledgments
We gratefully acknowledge the funding of the National Key Research and Development Program of China (2019YFC1605700), the Leading Talents of Thousand Talents Program of
Central China (19CZ0122), the National Natural Science Foundation of China (32102689), and the Outstanding Talents of Henan Agricultural University (30501055).
Declaration of interests
The authors declare no competing interests.
Resources
www.cdc.gov/parasites/cyclosporiasis
www.fda.gov/food/foodborne-pathogens/cyclospora
www.mayoclinic.org/diseases-conditions/cyclospora/symptoms-causes/syc-20353068
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