Tri-County health officials are investigating another outbreak of norovirus at several day care centers in southern Arapahoe and northern Douglas counties.They said it's the resurgence of a virus first diagnosed in that part of town last July."I have a child in this center," said Abe Monzon, referring to the KinderCare day care center near South Quebec and East County Line Road. "I'm very concerned." "It's not just a KinderCare issue ... You'd be hard-pressed to find a day care center or school in the area not affected by this," said Kelley Egre, a spokeswoman for the day care chain.Last September, Tri-County Health closed the Creme de la Creme day care center in Lone Tree for four days after 41 kids and several staff members came down with the virus.This time, health officials said they would not close any of the centers."One of the biggest reasons," said Deputy Director Bruce Wilson, "is that if children are ill, they could be placed (by their parents) in other centers (without telling the staff about the illness). Then we'd have a larger outbreak on our hands."Wilson said some parents are more concerned about not missing work than about not spreading germs."I don't agree with that," Monzon said. "I want this disease to be isolated so it doesn't spread. I don't want my son getting sick."Monzon said authorities should close the affected centers.Wilson said there are already rules in place to control the spread of the virus.He said any staff member or child who exhibits symptoms -- nausea, vomiting, stomach cramps or diarrhea -- should be isolated and immediately sent home. They should not be allowed back in the center until they've been symptom-free for two or three days, he added.Parents and staff should wash their hands frequently after using the restroom, changing diapers or toilet training, especially before eating or preparing food, health officials said.Wilson said people should avoid preparing or serving food if they have a gastrointestinal illness.He also said they should use a bleach-based household cleaner to thoroughly clean and disinfect contaminated surfaces.Agre said that all of the affected KinderCare centers have been cleaned."We have gone above and beyond in terms of cleaning and sanitizing the centers," she said.