The number of respiratory infections known as “walking pneumonia” is surging across the country, concerningly among young children, the Centers for Disease Control and Prevention said.

Bacterial infections from Mycoplasma pneumoniae, which can cause walking pneumonia, have surged since late spring, according to the CDC. The spike has been highest in children ages 2-4. Cases of "walking pneumonia" — a milder form of the lung infection pneumonia — have spiked in the United States, particularly among young children.

A new update from the CDC is sounding the alarm for parents of young children. The agency is tracking a rise in cases of “walking pneumonia” and other respiratory illnesses caused by the mycoplasma pneumoniae bacteria.