Ohio has seen a nearly fourfold increase in the number of diarrhea-causing infections linked to the cryptosporidium parasite commonly found in pools and water parks and spread when people swallow water contaminated with human feces, according to state and federal health officials.
Last year, Ohio health officials identified 1,940 people sick with cryptosporidiosis, also known as Crypto, which represented a 386 percent increase from the median number of cases (399) reported from 2012 through 2015, according to the U.S. Centers for Disease Control and Prevention (CDC).
The CDC also reported 24 Crypto-related outbreaks — or multiple cases in one location — in the state last year, and at least 10 of those outbreaks were associated with aquatic venues, according to the CDC and the Ohio Department of Health.
“We had people who had diarrhea go to the pool and swim in the pool, and (fecal) particles may have been left in pool water or in splash pads,” said Sietske de Fijter, state epidemiologist at the Ohio Department of Health. “When we interviewed them as to where they had gone during their incubation period before they became ill, they mentioned many different locations. So it’s hard to tease out where the outbreaks started.”
Crypto is “particularly hard to kill,” according to Jenny Bailer, health commissioner for the Butler County Health Department.
“It forms a hard coating around itself, kind of a shell,” Bailer said. “It has to bask in chlorine for quite a while at a high concentration in order to kill it, so that’s why occasionally there are these outbreaks because it’s really a tough thing to get rid of.”
The Butler County Health Department inspects 195 pools each season three times a season each and more often if needed due to disease outbreaks or complaints, she said.
There were 36 swimming-related and non-swimming-related Crypto cases between 2012 to 2016, but no actual outbreaks or large numbers of people ill from Crypto during that time, Bailer said.
When a person is diagnosed with Crypto, it is required by law that the person’s information be sent to the health department by the doctor or lab that diagnosed the disease,” Bailer said.
“When we receive a report, we are required to follow up with a phone call to conduct an interview with the ill person or their parent,” she said.
The health department’s communicable disease nurses ask “numerous questions” about where the person went, what they ate and what they did during the period of time when they would have become infected, Bailer said.
“Did they swim in any pools, did they swim in a river, did they swim in a lake?” she said. “Do they have reptiles at home? Did they handle a lot of different things, because you don’t just get Crypto from a swimming pool, you can get it from other places.
“From this we are often able to make an educated guess as to where they picked up Crypto, but not always,” Bailer said.
If a particular pool is identified, the health department doesn’t know with 100 percent certainty that Crypto originated from there but is “suspicious” and hands the information to its environmental staff.
Registered sanitarians then make a visit to the pool and pool management is required to follow CDC guidelines in “Fecal Incident Response Recommendations for Pool Staff.” That involves closing and “super chlorinating” the pool with levels of chlorine high enough, and in place for a specified period of time long enough to kill Crypto (or whatever organism is involved).
Once that is completed, it must be entered into a “pool record” so it can be noted in the future, she said, adding there is no method of testing for the cryptosporidium parasite.
Middletown Health Department is responsible for inspecting 32 pools, according to Carla Ealy, the department’s environmental health director.
“We go out once a month for the outdoor ones and quarterly for the indoor ones,” Ealy said.
Any Crypto cases reported by Middletown Health Department are investigated by Butler County Health Department, Bailer said.
Fairfield Aquatic Center staffers take chemical readings at the opening and closing of the pool each day during the season, as well as every two hours in between, according to Brad Williams, operations coordinator for Fairfield Parks and Recreation Department.
“We’re taking chlorine readings, alkalinity, PH, water clarity, water temperature,” Williams said. “We’re continually monitoring it.”
Bob Schappacher, facility manager for Fairfield Aquatic Center and a certified pool operator, said while state requirements call for a chlorine level of 1.0 ppm (parts per million), pool staffers for the center typically keep the pool at 2.0 or 3.0 ppm for the bacteria-destroying chemical.
“We always try to keep our chlorine levels a little higher than the low just to help, so if and when that does occur for a stool sample or if something happens in the pool, we’ve already got levels of chlorine that will be higher than normal,” Schappacher said.
There are 10 pools within the branches across the Great Miami Valley YMCA’s association and the maintenance schedule is “constant,” according to spokeswoman Liza Deaton.
“Lifeguards are tasked with checking the chemical levels at regular intervals throughout the day,” Deaton said. “In addition to the lifeguards, we also have maintenance staff and aquatics directors whose utmost priority is the safety of every person that visits our branches.”
The number of outbreaks in Ohio made up about a third of the 32 outbreaks reported so far to the CDC for 2016 at swimming pools or water playgrounds across the country. Last year’s outbreak figure was double the national figure from 2014, prompting the CDC to issue a nationwide warning about contaminated pool water just before the pool season begins on the upcoming Memorial Day weekend.
“To help protect your family and friends from Crypto and other diarrhea-causing germs, do not swim or let your kids swim if sick with diarrhea,” said Michele Hlavsa, chief of CDC’s Healthy Swimming Program. “Protect yourself from getting sick by not swallowing the water in which you swim.”
Swallowing just a mouthful of water contaminated with Crypto can make otherwise healthy people sick for up to three weeks with watery diarrhea, stomach cramps, nausea, or vomiting, and can lead to dehydration.
While Crypto is the most common cause of diarrhea illness and outbreaks linked to swimming pools or water playgrounds each year, it is not clear whether the number of outbreaks has increased or whether better surveillance and laboratory methods are leading to better outbreak detection, Hlavsa said.
“We don’t know what was different about last year,” she said. “What we do know is someone somewhere went swimming with diarrhea had an incident in the water, other people came around, drank that contaminated water and became infected. That’s how these outbreaks happen.”