Atypical pneumonia, also known as "walking pneumonia", is a pneumonia not caused by one of the more traditional pathogens and with a clinical presentation that contrasts to the "typical" pneumonia. It can be caused by a variety of microorganisms. When developed independently from another disease it is called primary atypical pneumonia (PAP).
The term was introduced in the 1930s and was contrasted with the bacterial pneumonia caused by Streptococcus pneumoniae, at that time the best known and most
Atypical pneumonia Search Trends: