Measles Resurgence and Record Cyclospora Outbreak Highlight Two Very Different Public Health Threats

The United States is confronting two unrelated but significant disease outbreaks this summer: the country’s largest measles resurgence in more than three decades and the largest recorded outbreak of cyclosporiasis in U.S. history.

Health officials say the outbreaks underscore different public health challenges — one driven by declining vaccination rates and the other by foodborne contamination that investigators are still working to trace.

Dr. David Williams, an emergency physician at Ellenville Regional Hospital, said the return of measles is particularly troubling because it is a disease that has long been preventable through vaccination.

“The virus has not changed,” Williams said. “It’s the same virus. That’s why we only need two vaccination doses.”

According to federal health officials, the U.S. has already reported more than 2,300 measles cases this year, surpassing last year’s total with several months remaining in 2026. The outbreaks have raised concerns that the nation could lose its measles elimination status after more than two decades.

Williams said outbreaks are occurring in communities where vaccination rates have fallen below the roughly 95% threshold needed for herd immunity.

“When that happens, people who are susceptible will develop measles,” he said. “It’s not just a rash. It’s a multi-system disease that weakens your immune system… and causes severe respiratory distress.”

He noted that many physicians practicing today have little firsthand experience diagnosing measles because it became so uncommon after the vaccine was introduced in 1963.

“I have not seen it,” Williams said. “I saw a case in California years and years ago. That’s it — one case in almost 40 years of practice.”

Early symptoms can resemble other illnesses

Williams said measles can initially look like common viral infections, making early diagnosis difficult.

Patients often develop cough, congestion, red eyes and respiratory symptoms before the characteristic rash appears.

“They’re very, very contagious,” Williams said. “One measles person can infect 12 to 15 other people.”

He said the measles, mumps and rubella (MMR) vaccine remains highly effective.

“The first vaccine dose gives you about 93% immunity,” Williams said. “The second gives about 98% immunity.”

He encouraged families preparing for back-to-school season and late summer travel to ensure vaccinations are current and to seek medical care if concerning symptoms develop.

“The number one thing is get the vaccine,” he said. “The virus does not change. We know what the virus is.”

Foodborne parasite investigation continues

At the same time, federal health officials are continuing to investigate a widespread outbreak of Cyclospora, a microscopic parasite that causes prolonged gastrointestinal illness.

The outbreak has sickened thousands of people nationwide. Investigators have linked one multistate outbreak to shredded iceberg lettuce while continuing to examine additional possible sources.

Williams said his emergency department has recently treated an unusually large number of patients with severe gastrointestinal symptoms.

“The last week we’ve seen so much GI complaints,” he said. “Yesterday I think I had seven or eight people with lots of watery diarrhea.”

Cyclospora infection commonly causes prolonged watery diarrhea, loss of appetite, cramping, bloating, gas and nausea.

Williams said most diarrheal illnesses resolve without emergency treatment, but patients experiencing frequent diarrhea should seek medical care before dehydration becomes severe.

“If you’re going every hour, you’re going to get dehydrated really quickly,” he said. “You should come to the emergency room for evaluation.”

He said emergency physicians can test for the parasite, provide intravenous fluids and replace lost electrolytes. Older adults and medically vulnerable patients may require hospitalization.

Following recalls, supporting local growers

Federal investigators continue working to identify the precise source of contamination. Williams said consumers should continue following public health guidance and food recall notices.

He also noted that many shoppers are turning to locally grown produce.

“I think the farmers market is a great option,” Williams said. “You know where it’s coming from.”

Regardless of where produce is purchased, he recommended washing fruits and vegetables thoroughly before eating them.

Image: In this Aug. 3, 2013, file photo are packages of Taylor Farms salads for sale at a supermarket in Omaha, Neb. The FDA retracted its only positive test for cyclospora, the parasite at the center of a multistate outbreak, on Taylor Farms lettuce. But the agency believes lettuce from the brand is still linked. (AP Photo/Nati Harnik, File)