Primary atypical pneumonia and Respiratory disease

Primary atypical pneumonia noun - An acute respiratory disease marked by high fever and coughing; caused by mycoplasma; primarily affecting children and young adults.

Respiratory disease and primary atypical pneumonia are semantically related. In some cases you can use "Respiratory disease" instead a noun phrase "Primary atypical pneumonia".

Respiratory disease noun - A disease affecting the respiratory system.

Primary atypical pneumonia and respiratory disease are semantically related. Sometimes you can replace phrase "Primary atypical pneumonia" with "Respiratory disease", this phrases are similar.