You might call it “generate paranoia.” On social media, videos show people taking out their fridges, insulting salads and debating whether cilantro is safe to eat.
It’s the Internet’s dramatic but expected response to the rise in cases of diarrhea that is spreading rapidly across the US, as health officials investigate whether salad greens may be contributing to the outbreak.
As of Tuesday, the US Centers for Disease Control and Prevention has received reports of 1,645 laboratory-confirmed cases of cyclosporiasis and is investigating an additional 5,100 reports. Cases of “explosive diarrhea” have been reported in all 34 states, with Michigan among the hardest-hit states.
The stomach bug is caused by cyclospora, a hard-to-trace foodborne virus that has historically been linked to fresh produce such as berries and lettuce. Currently, no specific food, brand, farmer or supplier has been definitively identified as the source of the outbreak.
That doesn’t stop people from freaking out, oversharing and making lots of dark memes. With any health scare, bad advice and myths spread as quickly as real illness. So we turned to health care experts to learn the facts.
“I would not recommend that people avoid the product,” said Dr. John Openshaw, an infectious disease physician and epidemiologist at Stanford University. “While the number of people affected by this or the current outbreak appears to be large, the risk remains very low for most people.”
What is cyclosporiasis?
Cyclosporiasis is caused by cyclospora cayetanensis, a microscopic parasite that is spread through fecal matter that attacks the small intestine. According to infectious disease experts at Johns Hopkins, it only takes a few tiny Cyclospora eggs to hijack your intestinal tract.
In the US, previous cyclospora outbreaks were often associated with fresh produce, including bagged salad mixes, cilantro, basil, raspberries, snow peas and green onions. Any contaminated and undercooked food can transmit cyclospora.
Unlike other gastrointestinal diseases, such as norovirus, cyclosporiasis is unlikely to spread directly from person to person. After the parasite has left the body of an infected person, it usually needs at least one to two weeks in the environment before it becomes infectious.
Abdominal cramps are a common symptom of cyclosporiasis, an infection caused by the cyclospora parasite.
What are the symptoms of cyclosporiasis?
The most common symptom is watery diarrhea that can be frequent and, according to the CDC, sometimes “explosive.” Other unpleasant symptoms may include stomach cramps, nausea, loss of appetite, bloating and gas, fatigue, vomiting, and low-grade fever.
Unlike deadly foodborne diseases such as listeria or E. coli, cyclosporiasis is usually not life-threatening. The biggest danger right now during the hot summer months is dehydration. “People who are sick and have trouble staying hydrated should talk to a doctor,” said Openshaw.
Symptoms usually begin about one week after exposure, although they can appear anywhere from two days to two weeks or more. Dr. Timothy Henrich, a professor of medicine at UCSF, said it’s common for people to have “waning and waning symptoms” for weeks to months. Some infected people may have little or no symptoms, she said.
Because symptoms can appear and pass, it is important to be tested for cyclosporiasis and talk to a doctor about treatment, which is usually well tolerated and “may reduce the chances of local fecal-oral spread,” Henrich said.
How high is the risk?
While cases of cyclosporiasis affect the entire country, the highest concentration of these outbreaks is in a small group of states, particularly in the Midwest. Jessica Steier, a public health scientist and CEO of Unbiased Science, said the risk remains low outside of those areas.
“That being said, until the specific source of the outbreak is identified, people outside of those states who are pregnant or immunocompromised can consider making a mistake,” Steier said.
The CDC says that only about 9 percent of people who get the parasite need to be hospitalized, but the risk of serious illness and lasting complications is much higher in the elderly, young children and others with weakened immune systems. The CDC said Tuesday it had not received reports of deaths related to the outbreak.
Health officials say it’s best to avoid bagged vegetables or pre-cut mixes to stay safe during the current cyclospora outbreak.
How can you reduce your risk?
So far, only lettuce and salad greens have emerged as a possible source, and the CDC says no specific product, grower, supplier, restaurant or grocery store has been identified.
As of Tuesday, there was no nationwide recommendation to discard lettuce. However, Michigan health officials have issued specific guidelines for lettuce during the current investigation, including buying whole heads of lettuce instead of bagged lettuce or pre-mixed salad kits (and discarding the three outer layers of leaves) and cooking greens when possible.
Although washing fresh produce may reduce your exposure to cyclospora and other foodborne contaminants, it will not guarantee that the parasite will be completely removed.
“Washing produce does not significantly reduce the risk of Cyclospora, and heating is still the gold standard for risk reduction,” Steier said. Cooking vegetables to an internal temperature of 158 degrees Fahrenheit or higher is the only sure way to kill the parasite.
Experts also warn against using soap, bleach or household disinfectants on the product. Fruits and vegetables can absorb soaps and detergents, which can make you sick, and the CDC says routine chemical washing is less likely to kill cyclospora.
Household appliances or countertop items such as a UV-generating washer, ultrasonic cleaner or ozone device will not make contaminated food safe for consumption, either. Steier confirmed that none of these methods have enough real-world evidence to support their use in killing the parasite.
What should you do if you have symptoms?
Experts advise that you contact a health care provider if you experience chronic diarrhea, especially if it is severe, lasts more than a week, or comes and goes. Drinking fluids is also important because prolonged diarrhea can cause dehydration.
Diagnosing cyclospora requires special laboratory tests, and the parasite is not included in routine stool tests. The CDC says patients sometimes need to provide multiple samples because cyclospora can be difficult to detect.
The standard treatment is the antibiotic combination trimethoprim-sulfamethoxazole, commonly sold under the brand names Bactrim and Septra. People who are allergic to sulfa drugs should discuss alternatives with a medical professional.
The CDC has not found a single source linking the outbreak.
When will we know the origin of the outbreak?
It can take weeks or more to identify the source of the outbreak because investigators must interview people who have the animal, compare what they ate and trace the food back through the supply chain. For cyclospora, that process is more difficult because symptoms often begin days after exposure, and people may not remember exactly what they ate.
Public health agencies have also faced staff cuts and funding cuts in recent years, making it difficult to quickly identify outbreaks and tell people what foods to avoid. A recent study found that states with more CDC support reported more outbreaks than those without such programs, suggesting that federal funding improves detection and management.
“Tracing any outbreak like this requires trained staff and resources – any reduction in those parts of the public health response will hamper efforts to find a foodborne outbreak and identify how a virus like cyclospora got into the food,” Openshaw said.
