Respiratory illness and Whooping cough

Respiratory illness noun - A disease affecting the respiratory system.

Whooping cough and respiratory illness are semantically related. In some cases you can replace phrase "Whooping cough" with "Respiratory illness", this phrases are similar.

Whooping cough noun - A disease of the respiratory mucous membrane.

Respiratory illness and whooping cough are semantically related. You can use "Respiratory illness" instead a noun phrase "Whooping cough".