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Bagged salad in Flordia led to an increase of cyclosporiasis. ByLorena/Stocksy
  • Cases of a parasitic gastrointestinal disease have been increasing in recent years, according to a new CDC report
  • Scientists suspect the recent increase in cases in the U.S. can be attributed, at least in part, to salad kits.
  • Cyclosporiasis is a parasitic infection that attacks the small intestine.

Cases of cyclosporiasis, an intestinal illness caused by a microscopic parasite that can spread by contaminated foods, have been increasing at an alarming rate across the United States.

Between 2016 and 2017, the number of reported cases of cyclosporiasis doubled in the U.S., growing from 537 to 1,194, according to a new reportTrusted Source from the Centers for Disease Control and Prevention (CDC).

The amount of annual cases tripled in 2018, reaching 3,519 cases. The trend continued, soaring to 4,703 cases in 2019.

Cyclosporiasis isn’t the most common gastrointestinal infection in the U.S., but more and more people are contracting the parasite, which typically thrives in tropical areas, domestically.

One state that was particularly hard hit in recent years is Florida, where the number of cyclosporiasis cases doubled from 254 in 2021 to 513 in 2022.

Scientists suspect the recent increase in cases in the U.S., especially the cases in Florida, can be attributed in part to a salad kit that contained the pathogenic parasite that led to a spike in cases in 2022.

At the same time, the diagnostic testsTrusted Source used to detect the parasite has become more widely available, helping us detect and track cases better.

“It is likely multiple factors that are responsible for increased US cases including more travel to areas in which the organism is prevalent, better diagnostic testing and awareness, and importation of food from Cyclospora-endemic areas,” Amesh Adalja, MD, FIDSA, a senior scholar at the Johns Hopkins University Center for Health Security and an infectious disease expert, told Healthline.

CyclosporiasisTrusted Source is spread through Cyclospora cayetanensis oocysts in the stools of infected people.

Feces containing the parasite, which is so small that it can only be seen through a microscope, can then contaminate food and water, says Adalja.

When ingested, the parasite can cause an infection called cyclosporiasis in about a week.

The parasite attacks the small intestine, typically causing watery diarrhea and severe bowel movements along with loss of appetite, stomach cramps, bloating, increased gas, and nausea.

Some people also experience flu-like symptoms, including body aches, headache, fever, and fatigue.

Infections may be more seriousTrusted Source in infants, older adults, and people who are immune-compromised.

Though cyclosporiasis infections can occur anytime and anywhere, they tend to be more common in tropical locations.

According to the CDC, foodborne outbreaks have been triggered by produceTrusted Source that’s been contaminated with the parasite, often in the spring and summer seasonsTrusted Source.

“Though cyclosporiasis typically occurs in endemic regions in the tropics and subtropics, foodborne outbreaksTrusted Source of cyclosporiasis have occurred—linked to etiologies such as raspberries, lettuce, herbs, and other vegetation (some of which were imported)—in non-endemic areas, including in the United States,” says Jessica Tuan, MD, a Yale Medicine infectious diseases doctor.

By using a genotyping tool, the CDC is able to identify genotyped specimens, and, in large outbreaks, link them to affected foods such as the salad kit behind Florida’s 2022 outbreak.

ResearchTrusted Source suggests that the increase in reported cases can be attributed to the availability of diagnostic tests used to detect gastrointestinal pathogens.

These testsTrusted Source, traditionally, are not routinely done in healthcare settings.

“Nowadays, given the improved sensitivity and specificity of tests to diagnose and detect Cyclospora particularly during ongoing outbreaks, this enhanced testing may be one of the factors — other factors potentially including change in climate — contributing to the increasing number of detected cases of cyclosporiasis,” says Tuan.

Left untreated, cyclosporiasis can cause symptomsTrusted Source for several weeks and potentially months.

It’s usually treated with a combination of two antibioticsTrusted Source, trimethoprim and sulfamethoxazole, along with antidiarrheal medications, and, in serious cases, IV hydration.

Recovery varies from person to person and is influenced by factors such as their age and underlying health.

Healthy individuals who get infected with cyclosporiasis are often able to recover without treatment, says Adalja.

“The timeframe of recovery from cyclosporiasis can vary based on the immune status of the infected individual, with immunosuppressed hosts typically having an increased risk for severe or prolonged illness,” Tuan said.

Cases of cyclosporiasis, an intestinal illness caused by a microscopic parasite that can spread through contaminated foods, have been increasing at an alarming rate across the United States. Scientists suspect the increase in cases can be attributed, in part, to a salad kit that contained the pathogenic parasite that led to a spike in cases in 2022. Better diagnostic testing along with climate change may be driving an increase in cases as well.