A microscopic parasite is infecting an unusually high number of people in Wyoming this year, with most of the illnesses occurring in Campbell County.
Health officials recorded 54 cryptosporidium infections in Wyoming for the first eight months of the year. That’s more cases than in either of the past two full years, according to Wyoming Department of Heath figures.
Nearly 75 percent of this year’s infections have been reported in Campbell County.
“We don’t fully understand all of the reasons for that,” said Kelly Weidenbach, an epidemiologist who monitors outbreaks of waterborne illnesses for the state.
It’s likely the actual number of infections is higher. Health officials would only be aware of cases where ill people sought medical attention.
Cryptosporidiosis is one of the country’s most common causes of waterborne diseases, according to the Centers for Disease Control and Prevention. Wyoming’s illness rate last year was more than double the national average.
The infection can cause diarrhea, stomach cramps, fever and weight loss. Symptoms usually last for a week or two, and often come in cycles that extend for a few days, according to the centers.
The parasites are found in natural bodies of water, such as lakes and rivers, but cases are also sometimes associated with swimming pools. An outer shell makes the parasites resistant to chlorine-based disinfectants.
The high number of infections in Campbell County might be related to the cryptosporidium outbreaks that occurred there in 2006 and 2007, Weidenbach said. Doctors also might be more familiar with the infection – making them more likely to identify and test for it.
The majority of Campbell County infections involved someone who visited Keyhole Reservoir, about 35 miles east of Gillette. State health officials don’t know why many of the infections have a link to Keyhole. All natural water sources have the parasites, with the concentration depending on a number of factors, including the depth and temperature of the water.
Despite the reported illnesses, Keyhole State Park remains open. Rangers there have been informing swimmers about the infections, but people they’ve spoken with haven’t reported problems, said Wyoming State Parks spokesman Gary Schoene.
Water levels at Keyhole were low the last time cryptosporidiosis was an issue. That’s not the case this time, Schoene said.
Health officials say the public can take steps to reduce the likelihood of illness. They recommend people avoid swallowing untreated water from lakes, rivers and pools; wash uncooked food; and frequently wash hands.