Cyclospora cayetanensis is a name that doesn’t exactly roll off the tongue—but that isn’t really the end of the GI tract we’re concerned about. Cyclospora is an intestinal parasite that causes a very unpleasant case of diarrhea. It’s normally pretty rare in the US, but this summer has seen a surge that is not entirely unexpected. Today alone I treated a number of patients with symptoms and a positive test.

Cyclospora is a one-celled parasite that causes the disease “cyclosporiasis”. It presents with stomach cramps, nausea, and especially diarrhea. The diarrhea can last for several weeks if untreated, but it’s pretty easy to treat, normally. People with normal immune systems will usually get better with or without drugs—eventually. But this is more than an inconvenience—there have been over 160 hospitalizations in Michigan so far. Older people are especially susceptible to dehydration from the loss of appetite and diarrhea.

Cyclospora comes from contaminated food. Because of the lifecycle of the parasite, the usual culprit is contaminated produce (the contaminant being human feces). When the parasite is passed through the gut it sits in the environment for a couple of weeks before it’s infectious, which is why you can’t pass it between people. But you can definitely get it from your salad. After eating the “bad salad” it can take a couple of weeks to get sick, making it harder to trace the source. Why are we eating salad contaminated with poop? As you can imagine, huge agribusiness farms aren’t always terribly concerned with worker safety and comfort, and bathroom and washing facilities might not always be readily available.

I went to an upscale market yesterday to grab some dinner. I love the kale tabbouleh they make. I picked it up, thought about chopped kale and parsley, and put it back on the shelf. At this point, we don’t know enough about this outbreak (I’ll explain why below) to feel comfortable with “business as usual”. It’s best to assume that any produce could be contaminated. Wash your hands with soap and water before and after handling produce. Wash all your fruits and vegetable thoroughly in running water—additives such as vinegar and other advertised products don’t help. You may want to avoid certain fruits and veggies with “crevices”, like berries. It’s also a good idea to peel off the first couple of layers of lettuce, cabbage, etc. Definitely DO NOT eat pre-cut fruits and veggies or bagged salad mixes. You’ll have to decide for yourself whether to eat restaurant food. Because the outbreak has not yet been traced definitively, we’re stuck being extra safe.

While the US has an incredibly safe and abundant food supply, we do suffer from plenty of outbreaks of food-borne diseases. Sometimes this is an “own goal” problem, as when people decide to drink “raw” unpasteurized milk. But usually it’s not a problem of consumer behavior. Contamination can happen anywhere from field to table—picking, processing, packing, preparation, etc. Some diseases are due to toxins secreted by bacteria, some from viruses or bacteria themselves, some from protozoa like Cyclopspora. This bug’s lifecycle does pose some challenges, given its long incubation period. Usual stool tests can miss cyclospora, prolonging the illness. Also the current administration has made deep cuts to our public health system, including cuts to the specific program that helps track Cyclospora outbreaks.

Because of the long incubation period it’s possible that we are on the “back end” of this outbreak—perhaps food recalls have removed contaminated products and the infections I’m seeing today were acquired a couple of weeks ago. It is just as likely that we are right in the middle of things with no clear end in sight. So keep it safe out there.