A 2-year-old boy has died and three other children were hospitalized after being sickened by a strain of E. coli linked to contact with animals at a San Diego County Fair, local health officials announced late Friday. The kids range in age from 2 to 13 and health officials determined that all had visited the fair earlier this month. The cause of the outbreak is under investigation, but all four kids reported visiting an animal area, the petting zoo, or had contact with animals at the fair, the San Diego County Health and Human Services Agency said in a release. The children contracted the E. Coli strain known as Shig-toxin-E. coli or STEC—which is linked to contact with animals. The San Diego Union-Tribune reported that fair officials were “devastated” to hear of the news, and have closed off the animal areas at the fair, which will continue through July 4.