Tri-County health officials said a home day care is a focal point in an E. coli investigation.A 3-year-old Aurora boy died from an E. coli infection Friday, and investigators are trying to figure out how he got it and if other children are at risk.Health officials say the boy went to a private home day care with about 12 other children, and that all of those parents have been contacted and are giving stool samples to see if they are infected.E. coli is normally a harmless bacteria, but some strains can be extremely dangerous if ingested."With the very young and very old, you have the potential for more severe illness that can require hospitalization," said Dr. Tista Goche of the Tri-County Health Department.Tri-county health investigators are still doing tests to see if the boy had one of those strains, but just in case, they're keeping a close eye on anyone who may have had contact with him at the home day care or at home, in case they get sick, too."At this time, we are investigating to see if some reports we've received are related to E. coli, but they're ones that we are well aware of and following very closely," said Bruce Wilson, deputy director of the Tri-County Health Department.Most E. coli infections come from eating undercooked beef or unwashed fruits and vegetables or drinking contaminated water. But the bacteria can also be passed from person to person, especially at day cares."I could be the fact the people didn't wash hands after changing the diaper of one child before moving to another child," said Wilson.Tri-County Health investigators said they don't know if that's where the little boy got infected, but there are simple steps everyone can take to prevent a tragedy like this."Washing your hands is probably the No. 1 thing you can do. Wash your hands before you make food. Wash your hands before you serve food," said Goche.She said that's because if an infected person doesn't properly wash his or her hands after using the restroom or changing diapers, then handles food or toys that children put in their mouths, they can spread the bacteria to other people.Symptoms of E. coli infection begin from two to 10 days after ingesting the bacteria and include sudden diarrhea, severe stomach pains and sometimes fever and vomiting.