Cyclosporiasis: Health Alert for New Hampshire Providers

July 29, 2014

Cyclospora illness in the United States is traditionally associated with travel to tropical or subtropical regions where Cyclospora infection is endemic. Since May 2014, Texas, Maine, and Massachusetts have observed unusual increases in the number of cases of cyclosporiasis, primarily among persons without a history of international travel. There have been no common food items identified to explain the current increases; previous domestic outbreaks have been linked to various types of imported fresh produce, including raspberries (1995-2000), basil (1997), snow peas (2004), salad mix (2013), and cilantro (2013).

Cyclosporiasis is a gastrointestinal illness caused by the parasite Cyclospora cayetanensis. Illness is caused by ingestion of the infective oocyst, such as through contaminated food or water. Cyclospora is not transmitted directly from person to person, because its life cycle requires a period of time in the environment to become infective. Symptoms begin approximately one week after ingestion of infective oocysts (range: 2-14 days) and typically include watery diarrhea with frequent and sometimes explosive defecation. Other common symptoms include loss of appetite, weight loss, abdominal cramping/bloating, increased flatus, nausea, and prolonged fatigue. If untreated, symptoms can persist for several weeks to months. Cyclosporiasis is typically treated with a 7-10 day regimen of trimethoprim-sulfamethoxazole (TMP-SMX).

NH Division of Public Health Services recommends the following:

  1. Be aware that there have been an increased number of cases of cyclosporiasis in the US, including states that neighbor New Hampshire.

  2. Consider cyclosporiasis as a potential cause of prolonged diarrheal illness in patients, regardless of travel history.

  3. If cyclosporiasis is suspected, specifically request testing for Cyclospora (most laboratories do not test for Cyclospora in a routine ova and parasite test).

  4. Report all laboratory-confirmed cases of Cyclospora to the New Hampshire Division of Public Health Services Bureau of Infectious Disease Control at 603-271-4496 (after hours 1-800-852-3345 ext. 5300).

Laboratory Testing for Cyclospora cayetanensis

Currently, the only tests available to assist in the diagnosis of cyclosporiasis involve microscopy, with several staining methods in use. Microscopy to identify Cyclospora cayetanensis is not routinely done when stool is examined for ova and parasites, and therefore requires that a clinician make a specific request to the laboratory. Because symptomatic persons may not shed enough oocysts in their stool to be detectable by laboratory examination, at least three stool specimens collected on different days should be tested before a negative result is reported.


Cyclosporiasis is reportable in New Hampshire and should be reported to the Bureau of Infectious Disease Control at 603-271-4496 (toll free at 1-800-852-3345 ext. 4496) or by fax to 1-603-271-0545. After hours, call 1-800-852-3345, ext. 5300 and ask for the public health professional on call.

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