Two students at Reese Elementary School in Lodi, CA, have reportedly tested positive for E. coli, and a seven-year-old boy was hospitalized. Lab tests are being done to identify other potential cases. to the San Joaquin County Health Department in Stockton, CA, an inspection of the school was inconclusive. Questionnaires to pinpoint a common source of bacteria have been done but have not yet been completed by all the impacted individuals, indicated San Joaquin County Health Officer Alvaro Garza, M.D., MPH, in a statement released Monday. “Environmental Health has made a site visit and found nothing unusual,” he noted, adding that, besides the two confirmed cases, there were additional lab results pending.

Meanwhile, the school’s principal said that immediate steps had been taken to prevent the spread of the bacterial infection.

“We have done the cleaning,” Gary Odell said. “We’ve had the public health department involved throughout. We’ve been in contact with the maintenance and operations department to make sure that everything that needs to happen here has happened to keep it clean and safe.” Odell said calls went out to parents on Monday evening, and the school would also be sending out a letter to them on Tuesday. The classroom the two students shared was thoroughly cleaned, and no E. coli was found in the school cafeteria. The father of the hospitalized boy, a second-grader, said his son started having stomach cramps and diarrhea last week and was in a lot of pain before the diagnosis was made. While some E. coli bacteria are harmless, some types can cause serious illness, or even death. The types of E. coli that can cause diarrhea can be transmitted through contaminated water or food, or through contact with animals or people. According to the U.S. Centers for Disease Control and Prevention (CDC), those of any age can become infected with E. coli. Very young children and the elderly are more likely to develop severe illness and hemolytic uremic syndrome (HUS) than others, but even healthy older children and young adults can become seriously ill. CDC advises these ways to prevent E. coli infection: Wash your hands thoroughly after using the bathroom, changing diapers, before preparing or eating food, and after contact with animals or their environments. Cook meat thoroughly, avoid raw milk or other unpasteurized dairy products and juices, prevent cross-contamination in food preparation areas by washing everything after contact with raw meat, and avoid swallowing water when swimming or playing.