Intestinal Parasite Cases Nearly Double in Connecticut

The Connecticut Department of Public Health is warning residents about a significant increase in cyclosporiasis, an intestinal illness caused by a microscopic parasite.

As of July 13, 2026, Connecticut had confirmed 35 cases. At the same point in 2025, the state had reported 19 cases.

This represents an increase of approximately 84 percent.

Connecticut officials said they were interviewing patients and monitoring the situation. At the time of the state announcement, no specific food source had been identified for the Connecticut cases.

A Much Larger National Increase

The national numbers have continued to increase.

According to the Centers for Disease Control and Prevention, 15,716 laboratory confirmed cases acquired inside the United States were reported between May 1 and August 17, 2026.

During a comparable period in 2025, the CDC received reports of 1,180 cases.

The 2026 national total included 828 hospitalizations and two deaths. The CDC cautioned that the figures were preliminary and that thousands of additional reports required further investigation.

The CDC is investigating multiple groups of infections. A large outbreak involving several states was linked to processed iceberg lettuce from central Mexico. Additional groups of cases remain under investigation.

The Connecticut Department of Public Health did not establish that the lettuce identified in the national outbreak caused the Connecticut cases. The state and national investigations must not be confused.

What Is Cyclosporiasis?

Cyclosporiasis is an intestinal illness caused by Cyclospora cayetanensis.

People can become infected after consuming food or water contaminated with the parasite. Outbreaks in the United States have frequently been associated with fresh produce.

The infection is not usually transmitted directly from one person to another. After the parasite leaves an infected person, it generally must mature in the environment before it can infect someone else.

Symptoms usually begin approximately one week after exposure, but they can appear between two days and two weeks or longer afterward.

The most common symptom is frequent watery diarrhea.

Other symptoms may include loss of appetite, weight loss, abdominal cramps, bloating, gas, nausea and prolonged fatigue.

Some patients may also experience vomiting, body aches, headaches or a mild fever.

Why the Illness Can Be Difficult to Recognize

Without treatment, symptoms may continue for several days, weeks or more than a month. Diarrhea and other symptoms may disappear temporarily and then return.

Some infected people may not experience symptoms.

Cyclosporiasis is not usually life threatening, but the illness can become serious. Persistent diarrhea can cause dehydration, weakness and nutritional problems.

Testing can also be difficult because many laboratories do not routinely test stool samples for Cyclospora. Patients experiencing prolonged watery diarrhea should contact a health care professional and mention the possibility of cyclosporiasis.

Treatment

The preferred treatment is a prescription medication containing trimethoprim and sulfamethoxazole.

Patients should not attempt to diagnose or treat the infection without professional medical advice. Individuals who cannot take this medication should speak with a qualified health care provider about their options.

People experiencing diarrhea should drink fluids to reduce the risk of dehydration.

How Residents Can Reduce Their Risk

Connecticut and federal health officials recommend washing hands with soap and water before preparing food and before eating.

Fresh fruits and vegetables should be rinsed thoroughly under running water before they are eaten, cut or cooked.

Washing produce can reduce the risk of infection, but it cannot guarantee that Cyclospora will be completely removed.

Cooking can kill the parasite. The CDC states that heating food to at least 158 degrees Fahrenheit, or 70 degrees Celsius, is effective.

Consumers should also monitor official food safety alerts and avoid eating products included in an active recall.

When to Contact a Medical Professional

Residents should contact a health care provider if they experience persistent or frequent watery diarrhea, especially when it is accompanied by fatigue, loss of appetite, weight loss, nausea or abdominal discomfort.

Immediate medical assistance may be necessary when a person develops signs of severe dehydration, including dizziness, confusion, fainting, very limited urination or an inability to keep fluids down.

Children, older adults and people with weakened immune systems may face a greater risk of complications from prolonged gastrointestinal illness.

An Investigation That Continues to Change

The Connecticut and national case totals may continue to change as health departments receive new reports and complete investigations.

Residents should rely on current information from the Connecticut Department of Public Health, the Centers for Disease Control and Prevention and the United States Food and Drug Administration.

This article provides general public health information and is not a substitute for medical diagnosis or treatment.