Cases of a Parasitic Infection Tripled Due in Part to Bagged Salad, What to Know

The United States has seen a significant rise in cases of cyclosporiasis, a gastrointestinal illness caused by a tiny parasite that can be transmitted through contaminated food.

According to a recent report from the Centers for Disease Control and Prevention (CDC), the number of reported cases of cyclosporiasis in the United States doubled from 537 to 1,194 between 2016 and 2017.

The number of annual cases increased significantly from 3,519 in 2018 to 4,703 in 2019.

Cyclosporiasis is an uncommon gastrointestinal infection in the U.S., but it is becoming more prevalent among people. The parasite that causes this infection is usually found in tropical areas but is now being contracted domestically.

Florida had a rough time in the past few years. The number of cyclosporiasis cases in Florida increased dramatically. In 2021, there were 254 cases, but in 2022, that number doubled to 513.

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.

The diagnostic tests for detecting the parasite have become more accessible, enabling us to improve our ability to detect and monitor cases.

“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.

What is cyclosporiasis?

Cyclosporiasis is caused by tiny organisms called Cyclospora cayetanensis, which are found in the feces of infected individuals.

Feces that have the parasite, which is extremely tiny and can only be seen with a microscope, can easily contaminate food and water, according to Adalja.

When the parasite is consumed, it can cause an infection named cyclosporiasis in approximately one week.

The harmful organism attacks the part of the body that helps digest food, usually resulting in loose stools and intense stomach movements. This is accompanied by a reduced desire to eat, painful stomach contractions, feeling full and gassy, and a feeling of wanting to vomit.

Some individuals may also have symptoms similar to those of the flu, such as muscle pain, a headache, a high body temperature, and tiredness.

Infections can be more severe in babies, older people, and those with weakened immune systems.

Where and how cyclosporiasis spreads

Though infections caused by the parasite cyclosporiasis can happen at any time and in any place, they are more frequently found in tropical areas.

According to the CDC, there have been cases where people got sick from eating fruits and vegetables that had a parasite on them. This usually happens more often in the spring and summer months.

“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 can find out the genetic makeup of specimens, and, in big outbreaks, connect them to the foods that caused the outbreak, like the salad kit connected to the Florida outbreak in 2022.

Research indicates that the rise in reported cases can be linked to the presence of diagnostic tests that are used to identify gastrointestinal infections.

These tests are not commonly 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.

How cyclosporiasis is treated

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

It’s typically treated with two types of antibiotics called trimethoprim and sulfamethoxazole. This is usually done along with medications to help with diarrhea, and in severe situations, intravenous hydration.

Recovering differs from person to person and depends on things like their age and overall health.

Healthy people who get infected with cyclosporiasis can usually recover without needing any treatment, according to 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.