This infectious respiratory illness is on the rise, especially among children. Here's what parents need to know.

An important message for parents, doctors are warning against an unusually high numbers of cases of a respiratory illness – especially in young children.

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.

According to the CDC, respiratory infections caused by the bacteria Mycoplasma pneumoniae have increased in the U.S. over the past six months, particularly among young children. In previous years, most pneumonia or acute bronchitis infections caused by the bacteria were found in school-aged children and teens.

The infection is causing what's called "Mycoplasma pneumonia." The rate of cases at emergency rooms had been increasing over the past six months with the peak hitting in August.

Infectious disease experts stress it’s not a cause for panic. Still, it’s important to be aware of symptoms to protect your children.