Cyclosporiasis is a parasitic illness caused by consuming contaminated food or water. Wildpixel/Getty Images
This summer, thousands of people across the U.S. have been affected by Cyclospora parasites causing havoc on their digestive systems. The country is witnessing the largest outbreak of this parasite recorded. As of July 28, the Centers for Disease Control and Prevention (CDC) reported cases in 45 states.
Michigan has been identified as the epicenter of cyclosporiasis, with over 10,000 individuals affected after consuming contaminated food, likely lettuce, containing Cyclospora parasites. These microscopic organisms rely solely on human hosts to reproduce.
The Parasite Lifecycle
Cyclospora parasites are almost invisible. They exist in dormant pods, called oocysts, on surfaces of vegetables and herbs. Vernon Carruthers, a microbiology professor at the University of Michigan Medical School, describes them as needing about a hundred linked end to end to span the head of a pin.
The lifecycle begins when a person swallows these oocysts, which travel through the digestive system to the intestines, where they respond to signals such as body temperature and digestive enzymes. The parasites then emerge and target the lining of the small intestine, invading cells to replicate.
Cyclospora parasites proliferate rapidly inside intestinal cells. This escalates to millions at the peak of infection. The parasites then differentiate into forms that combine to produce new oocysts, repeating this internal cycle.
The intrusion and damage caused by these parasites disrupt the intestinal lining, impairing nutrient absorption and leading to symptoms like nausea and diarrhea.
Transmission and Survival
Scientists caution that humans become infected primarily by ingesting contaminated food or water containing traces of human waste where Cyclospora is present. Fresh waste is not infectious. The oocysts need to mature in the environment, though the maturation timeline is unclear.
Cyclospora can infiltrate the food system through tainted soil, contaminated water, or by handling produce with unwashed hands. Industrial washing processes could even aid the spread. The pods are resilient, surviving adverse conditions like chlorine, sunlight, and cold.
Symptoms and Treatment
Infections can persist for weeks or months. Dr. Bobbi Pritt from Mayo Clinic highlights the complexity compared to typical viral stomach bugs. Antibiotics such as Bactrim, Septra, or Cotrim might help halt parasite replication, assisting the immune system.
Cyclosporiasis is rarely fatal, although its symptoms can be severe. In regions where Cyclospora is common, younger individuals tend to exhibit more symptoms than older adults, indicating possible immunity development over time.
Current Outbreak Mystery
Recent U.S. outbreaks of cyclosporiasis fluctuate, with current cases peaking significantly. Imported food supplies often introduce the parasite, particularly from countries with inadequate sanitary facilities.
This year’s widespread U.S. outbreak remains baffling. Dr. Pritt speculates that large doses of contaminated products entering high-consuming markets, such as Taco Bell with lettuce from Mexico, might be contributing factors. Taylor Farms had a voluntary recall of their contaminated lettuce in July.
North Carolina health officials suspect parsley and cilantro may be linked to infections. As investigations continue, experts recommend thoroughly washing and cooking produce to reduce infection risks.