A 2-year-old boy died and three children fell ill after contracting E. coli at the San Diego County Fair petting zoo, according to a report.

The boy had been hospitalized and died from complications. San Diego Health and Human Services announced the boy’s June 24 death on Friday, CBS News reported.

The three sick children are between the ages of 2 and 13 and came down with symptoms within days of visiting the fair, between June 8 and 15, the agency said. No symptoms have been reported since June 16.

The fair is scheduled to stay open through July 4, but the zoo, and all other animal areas, are closed.