Federal health officials are asking health care providers across the country to be on the lookout for foodborne infections from the Cyclospora parasite because more than double the number of cases have already been confirmed this year and the peak season is not yet ended.

To view the full sized graphic about the transmission and life cycle of Cyclospora parasites, please click on the image.

From May 1 through Aug. 2 this year in the United States there were 206 confirmed cases of cyclosporiasis, compared with 80 confirmed cases during that time period in 2016, according to an advisory posted Monday by the Centers for Disease Control and Prevention. Such advisories are relatively rare, with Monday’s being only the sixth from the CDC this year.

“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),” according to the CDC advisory.

“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.”

The CDC advisory did not include a state-by-state breakdown of confirmed infections, but it did report that at least 18 people have required hospitalization. The 206 confirmed infections have been reported from 27 states, most of which have reported relatively few cases, CDC reported.

“Healthcare providers should consider a diagnosis of cyclosporiasis in patients with prolonged or remitting-relapsing diarrheal illness,” the CDC advised. “… Several stool specimens may be required because Cyclospora oocysts may be shed intermittently and at low levels, even in persons with profuse diarrhea.

“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.”

The federal advisory follows Cyclospora outbreak reports from state and local public health officials across the country

On Aug. 1 the Texas Department of State Health Services reported confirmed cases in the Lone Star state had more than doubled in the second half of July, increasing from 68 on July 17 to 160 as of Aug. 1.

The NYC Health Department reported on July 24 that it has been tracking an increase of Cyclospora parasite infections there.

“A total of 27 cases were reported between Jan. 1 – June 30, 2017, compared to 13 cases in 2016, and 21 cases in 2015 during the same time period,” the New York City department reported. “In June 2017 there were 22 cases reported, compared to 18 in June 2015 and 10 in June 2016.”

As with the CDC and Texas advisories, the New York City department is encouraging health care providers to watch for people with symptoms of Cyclospora infection and specifically test for the foodborne parasite.

The most common symptom of cyclosporiasis is watery diarrhea, which can be profuse, according to the CDC. Other common symptoms include anorexia, fatigue, weight loss, nausea, flatulence, abdominal cramping, myalgia, vomiting and low-grade fever.

Symptoms of cyclosporiasis begin two days to more than two 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.

People become infected with Cyclospora by consuming food, water or other beverages contaminated with the parasite. It is not transmitted directly from one person to another person, according to the CDC.

Infections spike despite preventive measures
The number of people in the United States infected from Cyclospora parasites has been peaking annually in June and July for several years, with the vast majority of illnesses reported from May through August.

Because of multiple outbreaks traced to fresh cilantro from the region of Pueblo, Mexico, the U.S. Food and Drug Administration stepped up inspection and enforcement there.

“Beginning in 2015, from April 1 through August 31, cilantro from this region has been and continues to be detained without physical examination at the U.S.-Mexican border and refused admission into the United States,” according to the FDA.

“The April through August time period aligns with the seasonality of previous (Cyclospora) outbreaks. Only cilantro producers on the Green List in the state of Puebla, who must comply with 11 minimal requirements on good agricultural and food safety practices as part of Mexico’s Systems of Risk Reduction of Contamination, are excluded from detention without physical examination under the import alert.”

The Texas case count for 2016 — 148 reported Cyclospora infections — was an improvement on the previous three years. Texas reported 351 cases of cyclosporiasis in 2013; 200 in 2014; and 316 in 2015.

The FDA suggested in September 2016 that the lower number of infections that year correlated with the first full season that FDA’s Import Alert for fresh cilantro from Puebla was in effect.

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