The Tulsa Health Department (THD) in collaboration with the Oklahoma State Department of Health (OSDH), Acute Disease Service (ADS) are investigating an outbreak of cyclosporiasis among residents of Tulsa and surrounding counties. As of August 1, 24 laboratory-confirmed cases of cyclosporiasis have been reported; symptom onsets have occurred from June 24 through July 26, 2018. The epidemiologic investigation suggests this outbreak is likely ongoing with persons currently experiencing illness and new cases being reported. Case ages range from 27 to 67 years (median = 43 years); 67% of cases are females. Nine (38%) cases are of Hispanic ethnicity. Twenty-one (88%) cases are residents of Tulsa County; although the other three cases are residents of Wagoner, Creek, and Rogers counties, case interviews have revealed at least two of these three individuals shopped and dined at establishments in the Tulsa area.

An investigation is underway to determine the source of this outbreak. Even though the epidemiology of this outbreak suggests a geographic cluster among residents in northeast Oklahoma, it is possible that related cases may not have been identified in other areas of the State as cyclosporiasis is not a notifiable condition. Cases of cyclosporiasis may also be associated with international travel. Public health officials are advising clinicians in Oklahoma to consider cyclosporiasis among patients with an acute, afebrile diarrheal illness, particularly in persons with diarrhea persisting > 1 week, and to report laboratory-confirmed cases with onsets since June 1 to the OSDH ADS epidemiologist-on-call at (405) 271-4060 or via the Public Health Investigation and Disease Detection of Oklahoma (PHIDDO) system.

Cyclosporiasis is a diarrheal illness caused by a single-celled parasite called Cyclospora cayetanensis. It is spread by consumption of contaminated food or water, which becomes contaminated after exposure to fecal matter from ill individuals. Cyclospora is not spread person-to-person. Symptoms of cyclosporiasis include watery diarrhea, loss of appetite, weight loss, bloating, stomach cramps, nausea, vomiting, muscle aches, and fatigue. Symptoms begin an average of 7 days after ingestion of the parasite and may last from several days to several weeks. Weight loss can be significant (exceeding 20 pounds in some cases). Some infected persons may not have any symptoms. Persons of all ages are at risk of infection. Treatment includes Bactrim or Septra (trimethoprim-sulfamethoxazole) and rehydration with fluids.

Recommendations for clinicians and laboratories

  • Clinicians should consider cyclosporiasis in patients presenting with an acute diarrheal illness with persisting watery diarrhea.
  • Laboratory testing for suspected cyclosporiasis includes gastrointestinal polymerase chain reaction (PCR) and/or ova and parasite (O&P) fecal examination.
  • Notify the clinical diagnostic laboratory about suspicion of Cyclospora disease to determine what testing is available, instructions for specimen collection and submission, and whether Cyclospora must be specified on the test order.
  • If ordering a gastrointestinal PCR panel, clinicians need to assure the PCR panel includes a target for Cyclospora.
  • If microscopic examination is ordered, stool specimens are typically submitted in an O&P collection kit. Stool specimens should be obtained early in the course of illness; optimum time is 1-3 days after onset of illness, during the early morning hours when the parasite(s) should be present in the greatest numbers. Many parasites are shed intermittently during the course of an infection; therefore, for initial detection,
  • 3 separate specimens should be collected on separate days, at a minimum of 24 hours apart – one every other day (over 5 days) is optimal but collection should not exceed 10 days.