Between May and October, the number of 2 to 4 year olds diagnosed after visiting the ER for a pneumonia-related illness has jumped from one to 7%.

Dr. Vin Gupta joins José Díaz-Balart to describe everything you need to know about the rise of "walking pneumonia" and other winter illnesses.

Milder cases of pneumonia, dubbed “walking pneumonia,” are on the rise in young children this year The temperature is dropping, and rates of a whole host of respiratory illnesses are doing the opposite. Among them is so-called walking pneumonia, a relatively mild form of pneumonia that has been unusually common in young children this year.

Cases of walking pneumonia have been increasing. What is walking pneumonia? How many cases have there been in Ohio? Here's what to know

Mycoplasma pneumoniae can cause "walking pneumonia." It usually causes a mild illness at first, giving people the impression they have a less severe infection.

Cases of walking pneumonia, a bacterial infection, have been on the rise in Michigan, according to the Centers for Disease Control and Prevention.

The other respiratory infection experts are watching closely is atypical (walking) pneumonia. Dr. Michel Hirsh, Worcester’s medical director and the chief pediatric surgeon at UMass Memorial Health, said he was told by Dr. Jean-Marc Gauguet, a diagnostic radiologist at UMass Memorial, that X-rays show a lot of kids with walking pneumonia.

Feeling run down but not "sick enough" to stay in bed? You might have a condition dubbed "walking pneumonia." This mild yet persistent form of pneumonia often sneaks up on people, leaving them with cold-like symptoms they try to power through.