Primary atypical pneumonia and Respiratory illness

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

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

Respiratory illness noun - A disease affecting the respiratory system.

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