The Minnesota Department of Health says waterborne illnesses are at a 10-year high for the state.
Department spokesman Doug Schultz says there have been more than 130 cases of waterborne illnesses so far this year. He says the majority of those cases came during two major outbreaks in late March in Duluth and in Brainerd.
"And those were both at pools," Schultz says. "But that doesn't mean there aren't risks obviously associated with beaches as well, and we do get a number of sporadic cases of illness reported to us. So we're only halfway through the year, and we have a high number and we have a lot more summer to go."
Schultz says most waterborne illnesses are caused by parasites, several that are resistant to chlorine.
He says people can prevent their spread by washing with soap before going into water. "And don't swim when you have diarrhea," he says. "That's probably the biggest rule we have to follow because we found that leads to the greatest number of illnesses."
He adds, "We also recommend don't swallow pool or lakewater. Wash your hands thoroughly after using the toilet. Change your diapers often and use a bathroom -- don't change them at poolside or on a beach."