Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Cyclospora infection

Peter F Weller, MD, MACP
Karin Leder, MBBS, FRACP, PhD, MPH, DTMH
Section Editor
Edward T Ryan, MD, DTMH
Deputy Editor
Elinor L Baron, MD, DTMH


Cyclospora cayetanensis is a foodborne and waterborne parasitic cause of diarrheal illness in children and adults; it is an intestinal coccidian recognized as a distinct protozoan genus [1].

Issues related to Cyclospora infection will be reviewed here. Issues related to other coccidial organisms that can cause gastrointestinal infections in humans (Cystoisospora belli, Cryptosporidium, Sarcocystis, and Toxoplasma) are discussed separately [2,3]. (See related topics.)


Humans are the only natural hosts of C. cayetanensis (figure 1). The role of animals as natural reservoirs is uncertain, and it is unclear whether zoonotic transmission occurs [4].

Cyclospora can occur as a locally acquired infection, among travelers, or in patients with HIV/AIDS [1,4]. The initial cases were noted in the 1980s when the AIDS epidemic emerged and Cryptosporidium was identified as an important opportunistic infection; in some cases, Cyclospora oocysts observed on acid-fast stains were misidentified initially as Cryptosporidia.

Cyclospora cayetanensis has a broad geographic distribution. The organism is most frequently reported in Latin America (especially Guatemala, Peru, and Mexico), the Indian subcontinent, and Southeast Asia. Risk factors for infection in endemic areas include contaminated water, food or soil, poor sanitation, and low socioeconomic status [4]. Many cases reported elsewhere have been imported by international travelers or contaminated food [5-11].

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Nov 2017. | This topic last updated: Nov 03, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Ortega YR, Sterling CR, Gilman RH, et al. Cyclospora species--a new protozoan pathogen of humans. N Engl J Med 1993; 328:1308.
  2. Relman DA, Schmidt TM, Gajadhar A, et al. Molecular phylogenetic analysis of Cyclospora, the human intestinal pathogen, suggests that it is closely related to Eimeria species. J Infect Dis 1996; 173:440.
  3. Pieniazek NJ, Herwaldt BL. Reevaluating the molecular taxonomy: is human-associated Cyclospora a mammalian Eimeria species? Emerg Infect Dis 1997; 3:381.
  4. Chacín-Bonilla L. Epidemiology of Cyclospora cayetanensis: A review focusing in endemic areas. Acta Trop 2010; 115:181.
  5. Hoge CW, Shlim DR, Rajah R, et al. Epidemiology of diarrhoeal illness associated with coccidian-like organism among travellers and foreign residents in Nepal. Lancet 1993; 341:1175.
  6. Bendall RP, Lucas S, Moody A, et al. Diarrhoea associated with cyanobacterium-like bodies: a new coccidian enteritis of man. Lancet 1993; 341:590.
  7. Madico G, McDonald J, Gilman RH, et al. Epidemiology and treatment of Cyclospora cayetanensis infection in Peruvian children. Clin Infect Dis 1997; 24:977.
  8. Lontie M, Degroote K, Michiels J, et al. Cyclospora sp.: a coccidian that causes diarrhoea in travellers. Acta Clin Belg 1995; 50:288.
  9. Petry F, Hofstätter J, Schulz BK, et al. Cyclospora cayetanensis: first imported infections in Germany. Infection 1997; 25:167.
  10. Crowley B, Path C, Moloney C, Keane CT. Cyclospora species--a cause of diarrhoea among Irish travellers to Asia. Ir Med J 1996; 89:110.
  11. Kansouzidou A, Charitidou C, Varnis T, et al. Cyclospora cayetanensis in a patient with travelers' diarrhea: case report and review. J Travel Med 2004; 11:61.
  12. Hall RL, Jones JL, Herwaldt BL. Surveillance for laboratory-confirmed sporadic cases of cyclosporiasis--United States, 1997-2008. MMWR Surveill Summ 2011; 60:1.
  13. Swaminathan A, Torresi J, Schlagenhauf P, et al. A global study of pathogens and host risk factors associated with infectious gastrointestinal disease in returned international travellers. J Infect 2009; 59:19.
  14. Ortega YR, Sanchez R. Update on Cyclospora cayetanensis, a food-borne and waterborne parasite. Clin Microbiol Rev 2010; 23:218.
  15. Herwaldt BL, Ackers ML. An outbreak in 1996 of cyclosporiasis associated with imported raspberries. The Cyclospora Working Group. N Engl J Med 1997; 336:1548.
  16. Herwaldt BL. Cyclospora cayetanensis: a review, focusing on the outbreaks of cyclosporiasis in the 1990s. Clin Infect Dis 2000; 31:1040.
  17. Ho AY, Lopez AS, Eberhart MG, et al. Outbreak of cyclosporiasis associated with imported raspberries, Philadelphia, Pennsylvania, 2000. Emerg Infect Dis 2002; 8:783.
  18. Centers for Disease Control and Prevention (CDC). Outbreak of cyclosporiasis associated with snow peas--Pennsylvania, 2004. MMWR Morb Mortal Wkly Rep 2004; 53:876.
  19. Insulander M, Svenungsson B, Lebbad M, et al. A foodborne outbreak of Cyclospora infection in Stockholm, Sweden. Foodborne Pathog Dis 2010; 7:1585.
  20. Centers for Disease Control and Prevention (CDC). Notes from the field: use of electronic messaging and the news media to increase case finding during a Cyclospora outbreak - Iowa, July 2013. MMWR Morb Mortal Wkly Rep 2013; 62:613.
  21. Centers for Disease Control and Prevention. Parasites - Cyclosporiasis Outbreak Investigations — United States, 2014. http://www.cdc.gov/parasites/cyclosporiasis/outbreaks/2014/ (Accessed on February 26, 2015).
  22. https://content.govdelivery.com/accounts/USCDC/bulletins/1af73ec (Accessed on August 14, 2017).
  23. Centers for Disease Control and Prevention. Cyclosporiasis Outbreak Investigations — United States, 2017. https://www.cdc.gov/parasites/cyclosporiasis/outbreaks/2017/index.html (Accessed on September 22, 2017).
  24. Tram NT, Hoang LM, Cam PD, et al. Cyclospora spp. in herbs and water samples collected from markets and farms in Hanoi, Vietnam. Trop Med Int Health 2008; 13:1415.
  25. Gibbs RA, Nanyonjo R, Pingault NM, et al. An outbreak of Cyclospora infection on a cruise ship. Epidemiol Infect 2013; 141:508.
  26. Galván AL, Magnet A, Izquierdo F, et al. Molecular characterization of human-pathogenic microsporidia and Cyclospora cayetanensis isolated from various water sources in Spain: a year-long longitudinal study. Appl Environ Microbiol 2013; 79:449.
  27. Baldursson S, Karanis P. Waterborne transmission of protozoan parasites: review of worldwide outbreaks - an update 2004-2010. Water Res 2011; 45:6603.
  28. Chacín-Bonilla L. Transmission of Cyclospora cayetanensis infection: a review focusing on soil-borne cyclosporiasis. Trans R Soc Trop Med Hyg 2008; 102:215.
  29. Giangaspero A, Marangi M, Koehler AV, et al. Molecular detection of Cyclospora in water, soil, vegetables and humans in southern Italy signals a need for improved monitoring by health authorities. Int J Food Microbiol 2015; 211:95.
  30. Connor BA. Cyclospora infection: a review. Ann Acad Med Singapore 1997; 26:632.
  31. Rabold JG, Hoge CW, Shlim DR, et al. Cyclospora outbreak associated with chlorinated drinking water. Lancet 1994; 344:1360.
  32. Sun T, Ilardi CF, Asnis D, et al. Light and electron microscopic identification of Cyclospora species in the small intestine. Evidence of the presence of asexual life cycle in human host. Am J Clin Pathol 1996; 105:216.
  33. Sánchez-Vega JT, Cabrera-Fuentes HA, Romero-Olmedo AJ, et al. Cyclospora cayetanensis: this emerging protozoan pathogen in Mexico. Am J Trop Med Hyg 2014; 90:351.
  34. Orozco-Mosqueda GE, Martínez-Loya OA, Ortega YR. Cyclospora cayetanensis in a pediatric hospital in Morelia, México. Am J Trop Med Hyg 2014; 91:537.
  35. Legua P, Seas C. Cystoisospora and cyclospora. Curr Opin Infect Dis 2013; 26:479.
  36. Kaminsky RG, Lagos J, Raudales Santos G, Urrutia S. Marked seasonality of Cyclospora cayetanensis infections: ten-year observation of hospital cases, Honduras. BMC Infect Dis 2016; 16:66.
  37. Fleming CA, Caron D, Gunn JE, Barry MA. A foodborne outbreak of Cyclospora cayetanensis at a wedding: clinical features and risk factors for illness. Arch Intern Med 1998; 158:1121.
  38. Huang P, Weber JT, Sosin DM, et al. The first reported outbreak of diarrheal illness associated with Cyclospora in the United States. Ann Intern Med 1995; 123:409.
  39. Hoge CW, Shlim DR, Ghimire M, et al. Placebo-controlled trial of co-trimoxazole for Cyclospora infections among travellers and foreign residents in Nepal. Lancet 1995; 345:691.
  40. Pape JW, Verdier RI, Boncy M, et al. Cyclospora infection in adults infected with HIV. Clinical manifestations, treatment, and prophylaxis. Ann Intern Med 1994; 121:654.
  41. Maggi P, Brandonisio O, Larocca AM, et al. Cyclospora in AIDS patients: not always an agent of diarrhoic syndrome. New Microbiol 1995; 18:73.
  42. Sifuentes-Osornio J, Porras-Cortés G, Bendall RP, et al. Cyclospora cayetanensis infection in patients with and without AIDS: biliary disease as another clinical manifestation. Clin Infect Dis 1995; 21:1092.
  43. Eberhard ML, Pieniazek NJ, Arrowood MJ. Laboratory diagnosis of Cyclospora infections. Arch Pathol Lab Med 1997; 121:792.
  44. DPDx. Key points for laboratory diagnosis of cyclosporiasis: Cyclospora cayetanensis. http://www.cdc.gov/dpdx/resources/pdf/benchAids/cyclospora_benchaid.pdf (Accessed on February 26, 2015).
  45. Varma M, Hester JD, Schaefer FW 3rd, et al. Detection of Cyclospora cayetanensis using a quantitative real-time PCR assay. J Microbiol Methods 2003; 53:27.
  46. Verweij JJ, Laeijendecker D, Brienen EA, et al. Detection of Cyclospora cayetanensis in travellers returning from the tropics and subtropics using microscopy and real-time PCR. Int J Med Microbiol 2003; 293:199.
  47. Lalonde LF, Gajadhar AA. Highly sensitive and specific PCR assay for reliable detection of Cyclospora cayetanensis oocysts. Appl Environ Microbiol 2008; 74:4354.
  48. Mundaca CC, Torres-Slimming PA, Araujo-Castillo RV, et al. Use of PCR to improve diagnostic yield in an outbreak of cyclosporiasis in Lima, Peru. Trans R Soc Trop Med Hyg 2008; 102:712.
  49. Shane AL, Mody RK, Crump JA, et al. 2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea. Clin Infect Dis 2017; 65:e45.
  50. Fox LM, Saravolatz LD. Nitazoxanide: a new thiazolide antiparasitic agent. Clin Infect Dis 2005; 40:1173.
  51. Diaz E, Mondragon J, Ramirez E, Bernal R. Epidemiology and control of intestinal parasites with nitazoxanide in children in Mexico. Am J Trop Med Hyg 2003; 68:384.
  52. Zimmer SM, Schuetz AN, Franco-Paredes C. Efficacy of nitazoxanide for cyclosporiasis in patients with sulfa allergy. Clin Infect Dis 2007; 44:466.
  53. Verdier RI, Fitzgerald DW, Johnson WD Jr, Pape JW. Trimethoprim-sulfamethoxazole compared with ciprofloxacin for treatment and prophylaxis of Isospora belli and Cyclospora cayetanensis infection in HIV-infected patients. A randomized, controlled trial. Ann Intern Med 2000; 132:885.