Cyclosporiasis facts for kids

Quick facts for kids Cyclosporiasis
Cyclospora cayetanensis
Classification and external resources
Synonyms	cyclosporosis
Specialty	Infectious disease
Patient UK	Cyclosporiasis

Cyclosporiasis is an illness caused by a tiny germ called Cyclospora cayetanensis. This germ is a microscopic parasite that can make people sick. It spreads through contaminated food or water, often when it has come into contact with human waste. Outbreaks have happened because of contaminated fruits and vegetables. It's rare for the illness to spread directly from person to person. However, travelers can sometimes get it, causing what's known as "traveler's diarrhea." This infection can lead to severe, watery diarrhea.

How Does Cyclosporiasis Affect You?

Sometimes, people with cyclosporiasis have no symptoms or only very mild ones. When symptoms do appear, they often include a lot of watery diarrhea, stomach pain and cramps, feeling very tired, a slight fever, not wanting to eat, and losing weight. The illness can be more serious for babies, older people, those who don't usually live in areas where the germ is common, and people with a weakened immune system. If the diarrhea is severe, it can lead to dehydration (not enough water in the body) and malnutrition (not getting enough nutrients).

What Causes Cyclosporiasis?

Cyclosporiasis mainly affects humans and other primates. When a tiny egg-like form of the parasite, called an oocyst, enters the small intestine, it settles there. It then grows for about a week.

The Parasite's Journey

The parasite especially affects a part of the small intestine called the jejunum. Doctors have seen inflammation in the intestines of people with cyclosporiasis. The oocysts are often found in the environment. This happens when contaminated water or human waste is used as fertilizer for crops.

How Do Doctors Find Cyclosporiasis?

Finding cyclosporiasis can be tricky because the oocysts are hard to see in poop samples. Special DNA tests, like PCR, and certain stains, like acid-fast staining, help doctors identify the parasite. If someone has diarrhea and recently ate foods like fresh leafy greens, basil, cilantro, or berries, especially during summer months, doctors might suspect cyclosporiasis.

How Can You Prevent Cyclosporiasis?

There is no vaccine for humans to prevent cyclosporiasis. A vaccine exists for sheep to help prevent problems during pregnancy.

Washing your hands with soap and water before making food is very important. Also, washing fruits and vegetables well under running water helps prevent the spread of this germ. Cyclosporiasis spreads through contaminated food or water. Regular cleaning methods might not kill the parasite.

How is Cyclosporiasis Treated?

Doctors often treat this infection with a medicine called trimethoprim/sulfamethoxazole, also known as Bactrim. Other medicines like nitazoxanide or ciprofloxacin can be used if someone cannot take Bactrim, but they might not work as well. To stop the spread, food should be cooked thoroughly. It's also best to avoid drinking fresh water directly from streams or unsafe sources.

Understanding Cyclosporiasis Outbreaks

Early Discoveries and Spread

The first cases of cyclosporiasis in humans were only reported recently, in the late 1970s. A British scientist named Ashford found three cases in Papua New Guinea. He noticed that the parasite's eggs took a long time to become infectious, about 8 to 11 days. This made the illness hard to diagnose. When looking at poop samples, the parasite's eggs could easily be mistaken for other things and missed.

In 2007, some researchers in India linked Cyclospora infection to a condition called Bell's palsy, which affects facial muscles. This suggested that cyclosporiasis might cause nerve damage or other problems in the body, not just in the intestines.

In 2010, a study in Kathmandu Valley found that people got Cyclospora from swimming. Researchers found the parasite in human waste around swimming areas. They believed that pool water, contaminated by the environment, might have caused the infections. This is because the parasite can survive even with chlorine in the water.

Studies in Nepal also found Cyclospora in vegetables like radish, cauliflower, cabbage, and mustard leaves. It was also found in sewage and river water. These studies showed that cyclosporiasis outbreaks in Nepal often happen during the rainy season, from May to September.

Cyclosporiasis and Weakened Immune Systems

When the AIDS epidemic began in the early 1980s, cyclosporiasis was recognized as a serious infection for people with weakened immune systems. Researchers have studied how cyclosporiasis affects people with low hemoglobin levels and those with weakened immune systems in places like Kathmandu. They looked at how the parasite spreads in the environment, including in soil, river water, and sewage.

Recent Outbreaks in the United States

Even though Cyclospora was once thought to be mostly in tropical areas, outbreaks are now happening more often in North America. The Centers for Disease Control and Prevention (CDC) has recorded many outbreaks in the U.S. and Canada since the 1990s. They also track many individual cases.

For example, between June and August 2013, over 631 people in 25 states got sick from cyclosporiasis. Investigations found that a contaminated bagged salad mix caused an outbreak in Iowa and Nebraska.

In 2015, the CDC learned about 546 confirmed cases across 31 states. In Texas, where many cases were reported, contaminated cilantro was found to be the cause.

From July to August 2017, 20 cases of cyclosporiasis were reported in Houston, Texas. These cases were linked to people who ate at a Mediterranean-style restaurant chain.

On July 31, 2018, the United States Department of Agriculture (USDA) warned the public about certain beef, pork, and poultry salads and wraps. These products might have been contaminated with Cyclospora from chopped romaine lettuce.

In June 2020, the CDC investigated an outbreak in the Midwestern United States. This outbreak was linked to bagged salad mix. A company called Fresh Express recalled many of its salad products.

In April 2025, the CDC reported an outbreak in Alabama that happened in June 2023. This outbreak was linked to cilantro from Mexico. Thirty-eight cases were confirmed, and nine more were suspected.

2026 Outbreak Investigation

In 2026, between May 1 and June 16, at least 145 cases of cyclosporiasis were reported across 17 U.S. states. Public health officials investigated possible links to contaminated fresh produce. The highest number of cases were reported in New York, Illinois, and Texas. In early July 2026, the CDC identified at least eight more groups of cases in Alabama, Kentucky, Michigan, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. Investigations for these groups were still ongoing. By July 14, the disease had spread to 34 states and infected nearly 7,000 people. On July 15, the disease was reported in Canada, with Quebec registering 85 cases. By July 22, more than 11,500 people were infected in 41 states.

Michigan health officials reported that evidence suggested lettuce or other leafy salad greens were the source of a large cyclosporiasis outbreak. This outbreak began in mid-June 2026. By July 13, the outbreak had resulted in 2,640 confirmed cases and 44 hospitalizations. This was a big increase from reports the previous week and marked the largest annual cyclosporiasis outbreak ever recorded in the state. Cases were concentrated in the state's southeast, especially Wayne County, where Detroit is located. Natasha Bagdasarian, Michigan's chief medical executive, described the case count as a "moving target" that was expected to keep rising. Michigan typically reports roughly 40 to 50 cases of the disease each year. Investigators continued efforts to find the specific contaminated food source and understand how widespread the outbreak was.

Separately, federal officials investigated earlier groups of cases in Illinois, New York (including New York City), Pennsylvania, and Texas. These appeared linked to Mexican restaurants, a grocery chain, and a catered event.

Federal health officials identified contaminated lettuce served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio, and West Virginia as a source of the outbreak. However, experts noted that not every illness necessarily came from a single source. The farming company Taylor Farms later voluntarily recalled several products containing iceberg lettuce. These products were sold in 27 states and had a possible link to the cyclosporiasis outbreak.

In late July, the FDA started investigating a new, separate cyclospora outbreak that sickened at least 72 people. This was different from the ongoing, larger lettuce-related outbreak. The source of this specific group of cases had not yet been identified.