Expert Angle: Cyclospora

Foodborne outbreaks often make headlines when they affect thousands of people, but the organisms behind them are rarely household names. One of those outbreaks is cyclospora, a microscopic parasite responsible for recurring infections across the United States that has renewed conversations about food safety, fresh produce and disease prevention.

SJU News talked to Diane M. Valentin, MS, MT (ASCP), MB, director of the medical laboratory science program, to learn more about the parasite, the recent outbreak and how people can protect themselves.

What is cyclospora?

Cyclospora is a human intestinal parasite. It's classified as a protozoan, meaning it's a single-celled eukaryotic organism. The parasite depends on human intestinal cells to complete its life cycle. Without a human host, it can't survive, so in many ways, it's completely dependent on us.

How common is this illness?

We tend to see cases increase every summer because warmer weather creates conditions that favor the parasite. This year, we're seeing a much larger spike, which some scientists believe may be influenced by factors such as climate change. It's also the time of year when people eat more fresh produce like berries, basil and lettuce – foods that have been associated with cyclospora outbreaks. So far this summer, 34 states have reported cases, and fortunately there have been no reported deaths.

Is there a known source of the latest outbreak?

On July 17, Taylor Farms released a statement saying the FDA informed them that their shredded lettuce products from Taylor Farms de Mexico in Guanajuato, Mexico, tested positive for cyclospora. Taylor Farms stated, “While the FDA traceback is indicating a specific independent farm, which represents less than 1% of the U.S.’s iceberg lettuce supply, as the potential source of the outbreak, we have removed all iceberg lettuce from the region indefinitely.” 

Where are the majority of the cases?

According to the CDC, as of July 13, more than 400 people infected with cyclospora had been reported to the CDC from Michigan, Ohio, West Virginia and Kentucky. Importantly, they noted that the true number of cases is likely higher, and that outbreaks may not be limited to those four states. They also reported 1,644 infections due to exposure from lettuce served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio and West Virginia.

What are practical steps people can take to reduce their risk of getting this foodborne illness? 

If you're eating foods that can be cooked, cooking is the most effective way to kill the parasite. Food should reach an internal temperature of at least 150 degrees Fahrenheit. Washing your hands and rinsing fresh produce are also important food safety practices, even though washing alone may not completely remove the parasite. Overall, the United States has a very safe food supply, with extensive monitoring happening behind the scenes. This outbreak is one of those instances where the system identifies a problem, and it's something we can all learn from.

What symptoms should people look out for?

I know it's a little taboo to talk about your poo, but that's often the biggest clue because the parasite affects the intestinal tract. People exhibiting symptoms of cyclosporiasis may experience diarrhea, along with loss of appetite, nausea and weight loss.

What does treatment look like?

It's important for anyone experiencing symptoms to contact their physician as soon as possible. Your doctor can order laboratory testing to confirm whether it's cyclospora. Confirming cases not only helps patients receive the appropriate treatment, but also gives public health officials a more accurate picture of the size and scope of the outbreak.