The CDC released a Health Alert Network (HAN) advisory(emergency.cdc.gov) on Aug. 7 saying there's been a notable increase in reported cases of cyclosporiasis. The agency said it's investigating this surge in cases along with the FDA and state and local health departments.
This photomicrograph of a fresh stool sample, prepared using a 10 percent formalin solution and stained with safranin, reveals the presence of three uniformly stained Cyclospora cayetanensis oocysts.
As of Aug. 2, the CDC had received reports of 206 cases of intestinal illness caused by the parasite Cyclospora cayetanensis among people who were infected in the United States and who became ill on or after May 1. That compares with 88 cases reported through Aug. 3 of last year. This year's cases have been spread across 27 states. Eighteen cases involved hospitalization, but no deaths have been reported.
Although the disease is known to be spread by consuming food or water contaminated with the parasite, the CDC has yet to identify a means of transmission and is continuing to investigate potential sources of infection.
Previous U.S. outbreaks have been traced to various imported fresh produce commodities, such as basil, cilantro, mesclun lettuce, raspberries and snow peas. So far, no commercially frozen or canned produce has been identified as a source of infection.
"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 agency said in its advisory.
It's important to note that the disease is not transmitted directly from person to person.
Epidemiology and Course of Illness
Cyclosporiasis is characterized by 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 be seen.
According to the CDC, disease symptoms begin an average of seven days after ingesting the parasite (ranging from two days to more than two weeks). If left untreated, the illness can last from a few days to a month or longer.
"Health care providers should consider a diagnosis of cyclosporiasis in patients with prolonged or remitting-relapsing diarrheal illness," the CDC's alert advised.
Most U.S. laboratories don't typically test for Cyclospora, even when stool is tested for parasites, so the CDC said health care professionals must specifically order testing for Cyclospora. Testing can be done via ova and parasite examination, by using molecular methods or through a gastrointestinal pathogen panel test.
Additionally, because cyclosporiasis is a nationally notifiable disease, health care professionals should report suspected and confirmed cases of infection to public health authorities.
Currently, the preferred treatment 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," the CDC said.
Recommendations for Clinicians
In summary, the CDC highlighted in its HAN advisory a few simple recommendations for health care professionals:
- Consider a diagnosis of cyclosporiasis in patients with prolonged or remitting-relapsing diarrheal illness.
- If indicated, specifically order testing for Cyclospora (multiple stool specimens may be needed because Cyclospora oocysts may be shed intermittently and at low levels regardless of symptoms).
- Report cases to local health departments and ask them for assistance with reporting or submitting specimens, if needed.
Related AAFP News Coverage
FDA, CDC Identify Possible Source of Cyclosporiasis Outbreak in Two States
Investigation to Determine Origin of Infections in Other States Continues
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