Increase in Reported cases of Cyclospora cayetanensis Infection, United States, Summer 2017

Distributed via the CDC Health Alert Network
August 7, 2017, 1400 ET (2:00 PM ET)
CDCHAN-00405

Summary

The Centers for Disease Control and Prevention (CDC), State and Local Health Departments, and the Food and Drug Administration (FDA) are investigating an increase in reported cases of cyclosporiasis. The purpose of this HAN Advisory is to notify public health departments and healthcare facilities and to provide guidance to healthcare providers of the increase in reported cases. Please disseminate this information to healthcare providers in hospitals and emergency rooms, to primary care providers, and to microbiology laboratories.

Healthcare providers should consider a diagnosis of cyclosporiasis in patients with prolonged or remitting-relapsing diarrheal illness. Testing for Cyclospora is not routinely done in most U.S. laboratories, even when stool is tested for parasites. Healthcare providers must specifically order testing for Cyclospora, whether testing is requested by ova and parasite (O&P) examination, by molecular methods, or by a gastrointestinal pathogen panel test. Cyclosporiasis is a nationally notifiable disease; healthcare providers should report suspect and confirmed cases of infection to public health authorities.

Background

Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis. People can become infected with Cyclospora by consuming food or water contaminated with the parasite; it is not transmitted directly from one person to another person. The most common symptom of cyclosporiasis is watery diarrhea, which can be profuse. Other common symptoms include anorexia, fatigue, weight loss, nausea, flatulence, abdominal cramping, and myalgia; vomiting and low-grade fever may also occur. Symptoms of cyclosporiasis begin an average of 7 days (range: 2 days to ≥2 weeks) after ingestion of the parasite. If untreated, the illness may last for a few days to a month or longer, and may have a remitting-relapsing course. The treatment of choice for cyclosporiasis is trimethoprim/sulfamethoxazole (TMP/SMX). No effective alternative treatments have yet been identified for persons who are allergic to or cannot tolerate TMP/SMX, thus observation and symptomatic care is recommended for these patients.

Cyclosporiasis occurs in many countries but is more common in tropical and sub-tropical regions. Previous outbreaks in the United States have been linked to various types of imported fresh produce (e.g., basil, cilantro, mesclun lettuce, raspberries, and snow peas). To date, no commercially frozen or canned produce has been implicated. In the United States, most of the reported cases and outbreaks have occurred during the spring and summer months, especially during May through August or September.

As of August 2, 2017, 206 cases of Cyclospora infections have been reported to CDC in persons who became infected in the United States and became ill on or after May 1, 2017. These cases have been reported from 27 states, most of which have reported relatively few cases. Eighteen cases reported hospitalization; no deaths have been reported. At this time, no specific vehicle of interest has been identified, and investigations to identify a potential source of infection are ongoing. It is too early to say whether cases of Cyclospora infection in different states are related to each other and/or to the same food item(s).

The number of cases (206) reported in 2017, is higher than the number of cases reported by this date in 2016. As of August 3, 2016, 88 Cyclospora infections had been reported in persons who became infected in the United States and became ill on or after May 1, 2016.

Recommendations for Healthcare Providers

• Consider a diagnosis of cyclosporiasis in patients who have prolonged or remitting-relapsing diarrheal illness.
• If indicated, healthcare providers should specifically order testing for Cyclospora, whether testing is requested by ova and parasite (O&P) examination, by molecular methods, or by a gastrointestinal pathogen panel test. Several stool specimens may be required because Cyclospora oocysts may be shed intermittently and at low levels, even in persons with profuse diarrhea.
• Report cases to local health departments. Contact the local health department if assistance is needed with reporting or submitting specimens.

For More Information

CDC Cyclosporiasis: http://www.cdc.gov/parasites/cyclosporiasis/

CDC Cyclosporiasis Resources for Healthcare Providers: https://www.cdc.gov/parasites/cyclosporiasis/health_professionals/index.html

CDC DPDx Laboratory Identification of Parasites of Public Health Concern:  https://www.cdc.gov/dpdx/cyclosporiasis/index.html