Cyclosporiasis is a parasitic illness caused by ingesting contaminated food or water. This summer, Cyclospora parasites have severely affected the digestive systems of thousands in the U.S. It marks the largest outbreak of this parasite seen in the country.
As of July 28, the Centers for Disease Control and Prevention reported cases of cyclosporiasis in 45 states. Michigan is notably impacted, with over 10,000 cases linked to contaminated lettuce.
Cycle of Infection
Cyclospora parasites thrive in the human digestive tract. They likely travel from areas where the parasite is common, hitching rides on crops, and reaching Americans through food.
These parasites are found dormant on vegetables or berries as microscopic pods, or oocysts. Once ingested, the oocysts travel to the intestines. In response to the gut’s environment, such as body temperature and digestive enzymes, the parasites activate.
“It would take about a hundred of them, linked end to end, to fit across the head of a pin,” explains Vernon Carruthers, a microbiology professor at the University of Michigan.
Intestinal Challenges
Once active, parasites attack the small intestine lining, replicating in vast numbers and causing symptoms like nausea and diarrhea. Infected intestinal cells are destroyed in the process.
The parasites’ growth cycle involves transforming into egg- and sperm-like forms, combining to form new oocysts. This conversion contributes to considerable intestinal damage.
Hardy Parasitic Pods
Parasitic pods are expelled in diarrhea. Initially non-infectious when shed, they mature in the environment before becoming hazardous. Cyclospora enters food systems via contaminated dirt, water, or unclean handling. The industrial washing process may also facilitate its spread, as water shared by produce can distribute the parasite widely.
Treatment and Immunity
While infections can last for weeks or months, a combination of certain antibiotics can help clear them by inhibiting parasite replication, enhancing the immune system’s response. Cyclosporiasis is rarely fatal, and immunity can increase with repeated exposures, common in tropical regions where the parasite is endemic.
Bobbi Pritt, a microbiologist at Mayo Clinic, notes that in endemic areas, younger individuals are more likely to exhibit symptoms compared to older individuals.
Outbreak Impact
Recent years have seen an increase in Cyclospora cases in the U.S., with outbreaks occurring sporadically. This year, however, the numbers have surged.
Imported food is a primary factor, as produce from countries with limited sanitation facilities brings risks of contamination. Specific cases, such as those linked to Taco Bell’s lettuce from Taylor Farms, have already been identified.
Public health officials are investigating other potential sources; North Carolina cites parsley and cilantro as possible culprits.
For now, the recommended precaution is washing and cooking fresh produce to lower infection risks.