Ninety-seven people have reported cases of cryptosporidiosis since last month's outbreak at Edgewater Resort and Water Park in Duluth, according to the Minnesota Department of Health. Twenty-two of those cases have been confirmed in laboratories.
Minnesota Department of Health (MDH) epidemiologist Trisha Robinson said the confirmed cases probably only represent a fraction of people who were actually sickened by the parasite. The investigation of the outbreak is still in progress.
"One different thing with cryptosporidiosis is the time from when a person is exposed to the time when they become sick can be as long as two weeks," Robinsons said. "Pools were closed on March 26, so we could still have people becoming ill two weeks after that, and their symptoms last anywhere from one to two weeks."
Another unrelated cryptosporidiosis outbreak in Brainerd last month resulted in 36 reported cases, with one case being confirmed in a laboratory.
The symptoms of cryptosporidiosis include stomach cramps, fevers or diarrhea. It can be contracted by swimming in infected water, contact with animals or even drinking raw unpasteurized milk.
"The way that cryptosporidiosis is typically introduced into the water park, and which we believe is the instance in both of these cases, is that it comes in from an infected user," Robinson said.
In 2011, there were 305 laboratory-confirmed cases of cryptosporidiosis, according to preliminary MDH numbers. Robinson said one person was hospitalized in each of the Brainerd and Duluth outbreaks.
"It certainly can be more dangerous to those who are immune-compromised: the children, the very elderly, pregnant individuals," Robinson said. "In Minnesota, we can see about 20 percent of individuals that would require hospitalization for this, so it is something that can cause very serious illness."
Robinson said that people who have been sick with diarrhea in the previous two weeks should avoid swimming in recreational waters.