Surge in Parasitic Infection Spreading Across the U.S.

A rising parasitic infection known for causing severe “explosive” diarrhea is becoming more prevalent in the United States. Public health agencies are working quickly to trace the origins of this sudden increase.

As of July 10, more than 3,100 cases of cyclosporiasis have been documented across 31 states, according to a recent count by NBC News.

States like Michigan, New York, Ohio, Illinois, and North Carolina are facing the most significant impact from this parasitic infection, which tends to become more common during the summer months, as noted by the U.S. Centers for Disease Control and Prevention.

The outbreak is attributed to the Cyclospora cayetanensis parasite, which typically spreads through food and water contaminated with feces from an infected individual—this pathway is referred to as the fecal-oral route. In the U.S., it’s often associated with fresh fruits and vegetables.

Once ingested, the parasite infects the small intestine, leading to watery, uncontrollable diarrhea accompanied by various gastrointestinal symptoms. Person-to-person transmission is rare.

Although cyclosporiasis is generally not life-threatening, as highlighted by the CDC, it can be extremely uncomfortable. Episodes of severe diarrhea can persist for weeks, potentially disrupting vacation plans. Some individuals may experience recurring symptoms, which can be particularly frustrating.

During the peak summer and fresh produce season, there’s been a notable increase in cyclosporiasis cases across several states. The CDC states there’s no evidence tying these clusters together up to now, but investigations are still underway.

“When we began noticing persistent diarrhea cases appearing, it was clear something unusual was happening,” Dr. Brian Kaminski, vice president of medical affairs at ProMedica Health System, which treats patients in Michigan and Ohio, shared with NBC News. “That trend seems to be ongoing.”

Regions Experiencing Case Increases

Nationally, infections have been on the rise since the spring.

According to the latest surveillance data from the CDC, at least 843 cases of cyclosporiasis have emerged in 31 states since May 1. (This figure doesn’t represent all recent cases reported by state health departments.)

Out of those infected, at least 86 required hospitalization.

On July 10, the CDC indicated it was aware of over 1,500 cases needing further analysis to confirm whether they were indeed domestically contracted cyclosporiasis.

The CDC also mentioned that the actual number of cyclospora infections in the U.S. is likely higher since many people recover without seeking medical attention or being tested.

Health departments in several states have reported sharp increases in cyclosporiasis cases directly to TODAY.com and NBC News.

Michigan

In Michigan, health officials are witnessing an unprecedented “sudden and large” surge in infections with the diarrheal parasite. As of July 10, there have been 1,562 reported cases since late June, according to the Michigan Department of Health and Human Services. This figure is about 25 times greater than the state’s annual average of around 40-50 cases, as stated by an MDHHS spokesperson.

The majority of Michigan’s cases are concentrated in Southeast regions including Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland, and Livingston counties.

Ohio

As of July 10, Ohio’s Department of Health reported at least 397 cases of cyclosporiasis in 2023, with 171 of those occurring since late June, according to an Ohio Health spokesperson.

The recent spikes in Michigan and neighboring Ohio might indicate the presence of an “epidemic cluster,” Kaminski noted.

New York

New York state has recorded roughly 394 cases since May 1, as indicated by a health department spokesperson on July 9. Typically, the state sees around 500-700 cases annually.

The spokesperson remarked that the current case counts don’t significantly deviate from what’s expected for this time of year.

Illinois

The Illinois Department of Health informed NBC News that the state has documented 141 cases so far this year, which is considered “higher than average,” though no specific cause has been identified.

North Carolina

As of July 6, North Carolina reported at least 110 cyclosporiasis cases since May, according to a statement from the state’s Department of Health.

Colorado

Colorado has seen 90 cases of cyclosporiasis up to this point, as relayed by a state public health spokesperson.

Indiana

Indiana reported around 72 cases since May 1, as per a state spokesperson’s comments to NBC News.

Texas

Texas has logged 48 cases between May 1 and July 6, with five hospitalizations and no reported deaths. No common source has been identified so far, according to the Texas Department of Health.

Understanding the Cyclosporiasis Situation in the U.S.

It’s not unusual for cyclospora infections to rise around this period, typically from May to August, according to the CDC.

“This year, several states have observed an uptick in cases in the past two weeks compared to the same time in 2022,” the CDC noted.

However, the agency clarified that it “has no evidence of a single, multistate Cyclospora outbreak connecting these cases currently reported in the media,” a spokesperson conveyed in an email to NBC News.

The CDC and FDA are closely monitoring clusters in various states but stated they are not ready to classify the current numbers as definitively unusual until investigations are complete.

The sharp rise in cyclosporiasis cases in Michigan and other states has instigated inquiries into a possible common source. So far, no specific food item, grower, or supplier has been pinpointed.

The prevailing theory is that contaminated fresh produce may be behind the spike, as shared by Dr. Natasha Bagdasarian, Michigan’s chief medical executive. Previous outbreaks have been linked to salad greens, raspberries, basil, cilantro, green onions, and snow peas.

Health officials encourage anyone experiencing symptoms of cyclosporiasis to seek medical attention.

Symptoms of Cyclosporiasis

The primary symptom of cyclosporiasis is a sudden bout of watery diarrhea. The CDC notes that these episodes are often frequent and “explosive.”

Alongside diarrhea, individuals may experience severe stomach cramps, bloating, vomiting, nausea, loss of appetite, and fatigue, according to the Cleveland Clinic.

Symptoms can last several days to weeks or even longer. Diarrhea may occur in cycles, returning after seemingly improving, the CDC advises.

It can take up to 14 days post-exposure to contaminated food or water for symptoms to manifest.

Compared to norovirus, another common GI illness, cyclosporiasis typically has a longer incubation period and is more likely to result in diarrhea and cramps rather than vomiting, Bagdasarian noted.

Most healthy individuals will recover without treatment, as per the CDC, but an antibiotic combination can help manage the infection. Those with weaker immune systems might face recurring symptoms and may need more extensive care.

If you experience signs of cyclosporiasis or sudden severe gastrointestinal distress, it’s advisable to contact your healthcare provider.

Preventing Cyclosporiasis

Avoiding food or water that might be contaminated is the only sure way to prevent cyclosporiasis.

Cooking food to a minimum internal temperature of 158 degrees Fahrenheit is the most efficient method to eliminate the parasite, according to MDHHS.

The New York State Department of Health provided additional tips to help prevent the spread of cyclospora:

• Wash your hands with soap and water before and after handling raw produce.
• Thoroughly wash all fresh produce under running water before eating.
• Use a produce brush on fruits and vegetables when feasible.
• Cut away any damaged parts on fresh produce before consumption.
• Refrigerate fruits and vegetables (cooked or fresh) within two hours of preparation.