A student at a preschool in northwest suburban Bartlett has been diagnosed with the coronavirus.

The Cook County Department of Public Health notified School District U-46 officials Thursday that a student at the Independence Center for Early Learning has a confirmed case of COVID-19, Supt. Tony Sanders wrote in a letter to families.

“The student has been isolated and is expected to remain in isolation/self quarantine to prevent spreading the virus,” Sanders wrote.

The child’s age and gender have not been released, but the school serves children between 3 and 5 years old.

Doctors in areas hardest hit by COVID-19 warn they're running low on essential supplies as President Donald Trump enacts the Defense Production Act to aid response.

The child could be the youngest COVID-19 patient in the state so far. State officials previously said that cases were reported in people ranging from 9 to 99 years old.

The death toll for the virus in Illinois rose to four Thursday as the case total hit 422.

District U-46 schools will remain closed at least through March 30, according to Sanders.

“As I have shared, we have been making plans in the event we need to remain closed beyond March 30, including Phase 2 of our Distance Learning Plan that will be released tomorrow,” Sanders wrote in the letter on Thursday. “However, we will await further guidance from the Governor and state health officials on whether schools will remain closed past March 30.”