Waterborne disease outbreak is traced to Duluth water parkThe Edgewater Resort and Water Park closed Monday after three confirmed cases of diarrheal disease.
By: John Lundy, Duluth News Tribune
An outbreak of a waterborne diarrheal disease has been linked with Duluth’s Edgewater Resort and Water Park, a state health official said on Tuesday.
Three cases of cryptosporidiosis have been confirmed and six more are suspected in Minnesota and Wisconsin, said Trisha Robinson, an epidemiologist for the Minnesota Department of Health who specializes in the waterborne disease. The cases involved both adults and children, and all of those who came down with the illness spent time at the water park this month.
Both cryptosporidiosis and the parasite that causes it, Cryptosporidium, typically are shortened as Crypto.
Robinson said many other cases may have gone unreported. “For every confirmed case, there’s usually 98.6 additional cases,” she said.
It can take anywhere from two days to two weeks for symptoms to appear, she added.
“It is certainly possible and very probable that there are additional people who are ill out there,” Robinson said. “There could be people who may have not shown symptoms yet.”
The water park voluntarily closed on Monday afternoon, and all of the water facilities were treated with super-chlorination, said Leanne Joynes, vice president of sales and marketing for ZMC Hotels of Duluth, which owns the Edgewater. After going through that process, the water park reopened at 10 a.m. on Tuesday.
Robinson confirmed that super-chlorination would remove any threat of Crypto. The parasite survives chlorination at ordinary levels, but it’s destroyed when the chlorine is brought up to 20 parts per million and kept there for 13 hours. Once that is done, and the chlorination is dropped to normal levels, it’s safe to reopen a facility, she said.
Crypto is one of the most frequent causes of waterborne illness in the United States, according to the Centers for Disease Control and Prevention. The best-known outbreak took place in Milwaukee in 1993, when 403,000 residents of the metropolitan area became ill after drinking contaminated drinking water.
Today, most cases are transmitted via recreational waters, Robinson said. She typically investigates between one and three outbreaks each year.
The parasite is spread through the feces of infected humans, according to the Wisconsin Division of Public Health
Symptoms of the disease can include watery diarrhea, abdominal cramping, nausea, dehydration and sometimes a low-grade fever, said Andrea Kubarek, a Douglas County public health nurse. Symptoms generally persist for two weeks, she said.
“You might not even know you had it unless you were tested for it,” Kubarek said.
The Douglas County Department of Health and Human Services received one report of crypto, said Pat Schanan, the department’s director. The case was referred to the Minnesota Department of Health.
Although crypto can be fatal, “fortunately for most people with healthy immune systems, that is not the case,” Robinson said.
Robinson stressed that people typically remain infectious for two weeks after the symptoms disappear.
“If you currently have diarrhea or have had diarrhea within the past two weeks, we do not want you going into any type of recreational water facility,” she said.
Individuals with symptoms of the disease should see their health-care provider, Robinson added.
The Edgewater water park opened in December 2005. It closed in January of this year for maintenance and repairs but never previously had closed for health-related reasons, Joynes said.
Robinson said the outbreak doesn’t necessarily reflect badly on the water park.
“Crypto can survive in even properly maintained facilities,” she said.