Cyclosporiasis: Unpacking the explosive parasitic outbreak

The parasite cyclospora is making its way across the U.S., causing more than 7,000 cases of intestinal illness that are lasting anywhere from days to a month.

Dr. Andrea Perkins, director of Auburn’s Public and One Health program and a clinical assistant professor of infection control and biosecurity, shares insight into the cause of the outbreak, symptoms, how to avoid infection, and how public health experts work to track and prevent further cases.

Q: What is cyclosporiasis?

A: Cyclosporiasis is an illness caused by an organism called cyclospora cayetanesis, and that is what is classified as a parasite. You might have heard of other types of microorganisms like viruses, bacteria, fungi. Parasites are essentially a type of microorganism or germ that is living, and it needs to live in something else — in or on something else that is living.

This particular organism causes infection in the gastrointestinal tract. There’s a lot of different symptoms associated with cyclosporiasis, but the primary symptom and what we’re seeing a lot of with this outbreak is watery diarrhea. You might see headlines that are using the term explosive diarrhea. That can look different for different people. The illness can be very mild — some people may not even notice that they’re sick. Then some people can become very ill, and then everything in between that as well.

The symptoms of cyclosporiasis are primarily diarrhea, but you can also experience other symptoms: weight loss, loss of appetite, some cramping in the abdominal region, things like that. Some of the less common symptoms you might have are fever, body aches, those sorts of things. Symptoms usually show up sort of tricky. They can show up as early as a couple days or as late as a couple weeks, but usually it’s about a week after you’ve been exposed to the parasite.

The duration of illness is also sort of interesting with this particular germ. After you have been exposed, which usually occurs through ingestion either of contaminated food or water, you can fall ill and experience symptoms anywhere from a very short duration, a matter of days, or all the way to a month or longer. What’s sort of unique about this is that you may develop diarrhea — severe diarrhea, mild diarrhea — just for a short period of time, and then it may seemingly resolve. You might start to feel better, and then it can come back. It can sort of wax and wane over time, and that can last sometimes over a month or more.

Q: How is it contracted?

A: Cyclospora cayetanesis is transmitted through ingesting contaminated food or water sources, and it’s generally not spread from person to person. The reason for that is because once you ingest it, it is excreted out into the environment, and it needs to live in the environment and mature a little bit over the span of about a week or two before it is able to infect another person.

The question comes up, does it affect animals? You may be worried about your dogs or your cats at home, but this is something that primarily impacts humans.

Q: What is the treatment?

A: Right now, the treatment is antibiotics. You’ll want to talk to your healthcare provider. Right now, because we’re in the midst of an outbreak, there’s a lot more testing being done to definitively diagnose cyclosporiasis infections. Your doctor may decide to administer antimicrobial or antibiotic treatment to help resolve those types of infections.

Q: Should I go to the doctor if I think I may be infected?

A: A lot of times when people experience a mild bout of diarrhea, they won’t go to the doctor. But right now, especially because we are experiencing an outbreak that is affecting over 30 states now, it’s really important from a public health perspective that we can diagnose and get a better idea of how many cases are occurring and where they’re occurring throughout the country. We’re seeing the most cases in the state of Michigan, but we’ve got lots of states that are involved in this particular outbreak.

This is public health in action, what we’re seeing right now. One of the jobs of public health is to be always working in the background, performing surveillance, actively, passively, lots of different ways that they do this to understand what the normal number of cases of cyclosporiasis is that we see in Alabama or in other states.

The state right now that’s being hit the hardest is Michigan, and they’ve had, I think, as of [July 14] about 3,300 cases identified. We know that that’s a problem because public health has been doing its job historically. That is over somewhere between 30 and 40 times what they would be seeing at this time during a normal year.

Q: Are certain populations at higher risk?

A: The populations that are at higher risk are, like with many illnesses, are young, old, immunocompromised.

This particular outbreak seems to be linked to specifically leafy greens and bagged lettuce products. We’re not quite sure what the brand is or lot numbers or any of those sorts of things at this point, but it does seem that there is a signal pointing to those particular food products.

If you are going to be eating leafy greens, get it by the head and peel off the outer layers and rinse it under water. It’s always a good idea to wash your fresh produce. Right now, until we know a little bit more definitively what’s causing this illness or what the source is, it’s probably good to steer clear from fresh fruits and veggies. Cooking them to about 158 degrees is a good idea, or if you’re able to peel your fruits and veggies.

Q: What makes this different from other stomach bugs?

A: What makes this a little bit different is the high number of cases that we’re seeing. It’s not unusual that we’ll see cases of cyclosporiasis in the United States. A lot of times it’s linked to individuals who have traveled to subtropical or tropical areas. That’s where this organism tends to be endemic, or you see it more regularly. But we do see periodic cases popping up in the United States.

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