Public health officials investigate cyclosporiasis outbreak
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The State Hygienic Laboratory at the University of Iowa is working with the Iowa Department of Public Health and the Centers for Disease Control and Prevention to determine the source of an outbreak of cyclosporiasis, a rare intestinal illness that has been identified in nine Iowa counties.
The Iowa Department of Public Health announced on July 8 that 22 cases of cyclosporiasis were reported in the following counties:
- Linn County – 10 cases
- Fayette County – 3 cases
- O’Brien County – 2 cases
- Webster County – 2 cases
- Benton County – 1 case
- Des Moines County – 1 case
- Mills County – 1 case
- Polk County – 1 case
- Van Buren County – 1 case
Only 10 cases of cyclosporiasis have been identified in Iowa in the past 20 years.
Additional cases have been identified in Nebraska and other Midwestern states. Public health officials in these states and in Iowa are trying to identify possible common exposures. No specific source for the outbreak has been determined yet.
Infected people shed unsporulated (non-infective; immature) Cyclospora cayetanensis oocysts in their stool. Immature oocysts usually require at least one week under favorable laboratory conditions to sporulate (become infective). An unsporulated oocyst, with undifferentiated cytoplasm, is shown (far left), next to a sporulating oocyst that contains two immature sporocysts (A). An oocyst that was mechanically ruptured has released one of its two sporocysts (B). One free sporocyst is shown as well as two free sporozoites, the infective stage of the parasite (C). Photo courtesy of the CDC/DPDM.
Symptoms of cyclosporiasis, unlike other diarrheal illnesses, may last an average of 57 days in immune-competent patients, who may suffer five to 15 bouts of watery diarrhea per day. Fatigue and anorexia are prominent symptoms; others include nausea, flatulence, abdominal cramping, low-grade fever and weight loss. People who are immune-compromised will have more severe and longer lasting symptoms.
Cyclosporiasis is caused by the microscopic parasite Cyclospora cayetanensis. People can become infected with Cyclospora by consuming food or water contaminated with the parasite. Cyclosporiasis is not spread person to person.
In the United States, foodborne outbreaks of cyclosporiasis, identified since the mid-1990s, have been linked to various types of imported fresh produce, including raspberries, basil, snow peas and mesclun lettuce. No commercially frozen or canned produce has been implicated.
If you are experiencing symptoms consistent with Cyclospora infection, contact your physician. Diagnosis of cyclosporiasis can only be accomplished by a laboratory test. Your physician will provide an appropriate specimen collection kit and submission form which will then be sent to the Hygienic Laboratory for testing. Additional information is available on the IDPH website.