ST. LOUIS COUNTY • There have been 18 reported cases of the diarrheal illness known as crypto in St. Louis County in the last week, most linked to day care centers, health officials said Wednesday.

Ten of the illnesses were in children ages 1 to 4, and the others were in people between 10 and 59 years old.

A total of 56 cases have been identified in the county this year, compared to 10 cases by this time last year.

County health officials did not name the day care centers connected to the outbreak, citing state regulations.

The illness, cryptosporidiosis, is spread through contact with infected feces, most commonly in swimming pools and day care centers.

Crypto outbreaks have also been linked this summer to the RiverChase pool in Fenton and the Belleville municipal pool.