Canyon County health officials are testing a small number of sick people for a potentially dangerous intestinal illness after five toddlers at a day-care center contracted the same illness.

The culprit is E. coli 0157:H7, the strain of bacteria that most often grabs headlines because it can cause cause serious illness and sometimes is linked with undercooked restaurant meat.

The five children, all boys age 3 or younger, attended Little Legg's day-care center in Middleton.

None was sick enough to be hospitalized, Southwest District Health spokeswoman Laurie Boston said.

The day-care had received its regular annual inspection just 11 days earlier. At that time, 54 children were enrolled.

Southwest District Health officials believe the illness has run its course, Boston said.

"If there was going to be a lot more cases, they would have surfaced by now," Boston said.

KIVI-Channel 6 reported Friday that the owner of the daycare contacted health officials when she was notified late last week that a 7-month-old at her facility tested positive for E. coli.

Boston said at least one of the children who tested positive has attended other day-care centers in the Treasure Valley.

"If it was widespread, we'd probably be getting a lot of calls," Boston said.

Health officials are trying to determine where the children contracted the E. coli infections.

She said the children who tested positive for the bacteria are being kept home until the bacteria has cleared their system, and they test negative. Boston said that can take several weeks.

The day-care center has been sanitized, Boston said.

"They're being very cooperative," she said.

There are many strains of the E. coli bacteria, most of which are harmless, according to the U.S. Centers for Disease Control & Prevention.

Symptoms of E. coli infection include severe stomach cramps, diarrhea, bloody diarrhea, vomiting and low fever.

The CDC says the bacteria is spread in humans through ingestion of tiny or invisible amounts of animal or human feces.

There are many ways people can be exposed to the bacteria, including eating contaminated food, unpasteurized milk, water that isn't disinfected, or direct contact with the feces of infected people, such as while changing diapers.

Thorough hand-washing after using the bathroom and changing diapers and before handling food is the best ways to prevent E. coli illness.

Other ways to avoid E. coli poisoning include thoroughly cooking meat and avoiding raw, unpasteurized dairy products or juices.

People with symptoms of E. coli are being asked to call Southwest District Health Department, 455-5442.

Colleen LaMay: 377-6448; Katy Moeller: 377-6413