More than 20 students at a private Doral pre-K school have confirmed infections of the Salmonella bacterium, and the number is expected to double by next week, according to the Miami-Dade County Health Department.

Juan Suarez, regional environmental epidemiologist with the health department, said today he is looking into how the children became ill at Born 2 Learn, a private pre-kindergarten school.

The salmonella was confirmed in more than 20 children, ages 1 to 5 years old, over the past week, and as many as 60 others are showing symptoms, he said.