In the United States, more people are being infected with a parasite after eating lettuce.
On August 3, 2 deaths were reported.
Food-safety incidents usually end with the advice, “Wash it thoroughly before eating,” but that advice does not work very well this time.
3-line summary
1. This parasite does not all come off through washing alone.
2. 6,358 people have been confirmed to have been infected because of lettuce.
3. No affected shipments entering South Korea have been confirmed.
What happened
On August 3, the U.S. Centers for Disease Control and Prevention said that 2 people had died from this parasite. Both lived in Michigan and had underlying medical conditions. Death from this illness is rare even in the United States.
The parasite is called Cyclospora. This is also the name used to test for it in hospitals.
That does not mean healthy people are unaffected. For most people, it does not become life-threatening, but prolonged watery diarrhea can cause dehydration. Older people or those with underlying conditions may become more severely ill and remain ill longer.
The suspected source is iceberg lettuce (head lettuce). The investigation found that lettuce grown in central Mexico was contaminated, and distributor Taylor Farms recalled all lettuce from that area on July 17. This included lettuce sold in supermarkets as well as lettuce supplied to restaurants; in the United States, people who became ill after eating at Taco Bell are also included in this incident.
Patients began becoming ill from June 22 through July 31. The recall began on July 17, but many people had already become infected before then.
To answer the question you may have first: No affected shipments entering South Korea have been confirmed. There is no need to worry about tonight’s salad.
Still, this incident is worth looking at once. The method we turn to whenever there is a food-safety incident does not work this time.
Separate these two numbers
6,358 people have been confirmed to have been infected because of lettuce. They were reported in 15 U.S. states, and 278 of them were hospitalized.
However, about 1만 8,000 people—where 만 means ten thousand—are estimated to have contracted this illness in the United States this summer.
The two figures count different things. The latter includes every cause, not just lettuce. Health authorities are also investigating incidents separate from this lettuce case.
Even the confirmed 6,358 people is an undercount. Many people recover without going to a hospital, and confirmation by testing can take as long as 6 weeks, so recent cases may not yet be counted.
These figures are as of August 5. There were 1,947 people in 9 states on July 24, so the number tripled in 2 weeks.
*▲ The card above shows figures as of July 24. By August 5, 2 weeks later, the count had risen to 6,358 people in 15 states and 278 hospitalizations. The 2 deaths and the 27 states that received recalled products remain unchanged.*
Why it does not come off even when washed
This parasite spreads in an egg-like form enclosed in a hard shell. This shell does two things: it adheres well to vegetable surfaces and is not easily killed by disinfectants.
It is not eliminated by tap water or by the levels of chlorine used in processing facilities. The U.S. Food and Drug Administration states that chlorine disinfectants and commercially available vegetable washes have not been shown to work against this parasite. The Centers for Disease Control and Prevention also says to wash produce under running water, but that this does not mean it can be considered removed.
The condition that reliably kills it is heating. But lettuce is not usually eaten cooked, so that is not an answer available in the kitchen.
That is why this response focused not on individual washing, but on recall. U.S. authorities’ guidance is not “wash it better,” but “do not eat it; throw it away or return it to where it was purchased.”
This is also why such incidents have so far occurred only with foods eaten raw, such as raspberries, basil, and cilantro.
Symptoms come late and return after seeming to improve
Symptoms usually appear about 1 week after eating. They can appear as early as 2 days or as late as 2 weeks. That is why it is difficult to suspect something eaten yesterday.
Watery diarrhea is most common, along with loss of appetite, nausea, and bloating. Weight loss can also occur.
There is one more characteristic. If left alone, symptoms may seem to improve and then worsen again several days later repeatedly, and may continue for more than 1 month. This is why some people dismiss it as an upset stomach, then become ill again.
Testing is not easy either. This parasite is not included in standard hospital tests, so it must be requested separately. It may not appear in a single test, and several tests on different days may be necessary.
What to remember today
Do not wash recalled products. Because washing does not guarantee removal, discard them or return them to where they were purchased.
Continue washing other vegetables. It may not remove all of this parasite, but it remains a basic measure to reduce soil and other bacteria.
Do not simply dismiss prolonged watery diarrhea. If it continues for more than 1 week, or improves and then starts again, it is advisable to tell a doctor what and when you ate, as well as where you traveled.
In South Korea, food recall notices are posted by the Ministry of Food and Drug Safety on Food Safety Korea, along with the product name, manufacturer, and use-by date. The scope of a recall can expand as an investigation proceeds, so it is better to know where to check.
This was not an incident caused by someone failing to wash lettuce properly.
The less an instance of contamination can be prevented in the kitchen, the more we should look to recall notices rather than vegetable wash.
Sources
- U.S. Centers for Disease Control and Prevention Cyclospora Outbreak Linked to Iceberg Lettuce
- U.S. Centers for Disease Control and Prevention Investigation Update: Cyclospora Outbreak, July 2026
- U.S. Centers for Disease Control and Prevention Clinical Overview of Cyclosporiasis
- U.S. Food and Drug Administration Cyclosporiasis and Fresh Produce
- PBS News Michigan reports first 2 U.S. deaths in outbreak of cyclospora
- PBS News Taylor Farms recalls lettuce shipped to 27 states over cyclospora risk
- Ministry of Food and Drug Safety Food Safety Korea — Recall and Sales Suspension Information
The patient count follows the August 5 update from the U.S. Centers for Disease Control and Prevention. Because the investigation is ongoing, the figures may increase further.
This article is informational and summarizes publicly available health-authority materials; it does not replace medical diagnosis or treatment. If you have symptoms, please consult a medical institution.