Federal health officials are urging Americans to take extra precautions with fresh produce as a parasite linked to severe gastrointestinal illness continues to spread across the country.
The Centers for Disease Control and Prevention (CDC) has confirmed more than 800 cases of cyclosporiasis in more than half of U.S. states, while investigators are also looking into more than 1,500 additional suspected cases, suggesting the outbreak could grow significantly.
Data show between that between 1 and 10 California cases have been linked to a broader statewide outbreak as authorities continue tracking the spread.
The illness is caused by the microscopic parasite Cyclospora cayetanensis, which infects the small intestine after people consume contaminated food or water.
According to the CDC, infected people often develop watery diarrhea with “frequent and sometimes explosive bowel movements.”
The agency said symptoms usually begin about one week after exposure, although they can appear anywhere from two days to more than two weeks later. Gastroenterologist Dr. Ariel Malamud told KTLA that symptoms often start five to seven days after exposure.
State and federal health officials are continuing to investigate multiple outbreaks, but the source has not yet been identified.
In previous US outbreaks, Cyclospora has repeatedly been linked to fresh produce, including raspberries, basil, cilantro, green onions, snow peas, lettuce, mesclun and salad mixes. Research has also connected past outbreaks to blackberries, watercress, mangoes and vegetable trays.
Health officials in Michigan, one of the states hardest hit during the current outbreak, are beginning to suspect lettuce or salad greens may be responsible, although the investigation remains ongoing.
“I’m annoyed at cyclospora,” infectious disease expert Dr. Bruce Hirsch told WPIX. “Cyclospora is contaminating the most healthful, delicious, seasonal foods there are.”
The CDC says people become infected after eating food or drinking water contaminated with feces carrying the parasite. Unlike many stomach bugs, Cyclospora is unlikely to spread directly from person to person because it takes at least one to two weeks outside the body before it becomes infectious.
Officials recommend following proper food safety practices when preparing meals.
Experts also say some foods appear to pose much less risk.
“To date, no commercially frozen produce, cooked foods or peeled fruit have been associated with cyclosporiasis infection,” one study cited by WPIX found.
The CDC advises washing hands thoroughly with soap and water after using the bathroom and before preparing food. Alcohol-based hand sanitizers do not kill Cyclospora.
Dr. Erika Noel, an assistant professor at the University of Hawaii’s medical school and a pediatrician on Kauai, told WPIX that washing produce carefully can also reduce risk.
She recommends separating the leaves of herbs such as cilantro and basil while rinsing them, and trimming the roots and outer layer from green onions before rubbing them under running water.
Research suggests washing fruits and vegetables in a mixture of three parts water and one part vinegar may help remove the parasite, although vinegar does not kill it. Noel also recommends washing pre-packaged salad mixes again before eating them or choosing whole heads of lettuce and removing the outer leaves instead.
Produce with deep crevices or delicate surfaces — including broccoli, cauliflower and berries — can be harder to clean. Noel suggests cooking berries in pies or jams rather than eating them raw during the outbreak.
Thick, dirt-covered root vegetables such as carrots, potatoes and radishes also require extra care.
The CDC also recommends peeling fruits and vegetables whenever possible. For melons, the agency advises scrubbing the rind before cutting, since a knife can transfer germs from the outside into the fruit.
Cooking produce to an internal temperature of at least 158 degrees Fahrenheit can kill Cyclospora.
While cyclosporiasis is not usually life-threatening, the CDC warns that symptoms can last from several days to more than a month if left untreated and may disappear before returning again. People with weakened immune systems may face more severe or prolonged illness.
The infection is typically treated with the antibiotic trimethoprim-sulfamethoxazole, sold under brand names including Bactrim and Septra.
Anyone experiencing persistent diarrhea is urged to seek medical care, as diagnosing Cyclospora requires a special stool test that is not included in routine testing. Drinking plenty of fluids and resting are also recommended to prevent dehydration
