Many of the less common pneumonias have a high death toll and are occurring more often. Various special pneumonias are caused by the inhalation of:
- a foreign body
Pneumonia can also be caused by a bronchial obstruction such as a tumour.
Rickettsiae (considered something between viruses and bacteria, like a mycoplasma) cause Rocky Mountain spotted fever, Q fever, typhus, and psittacosis --diseases that involve the lungs to a greater or lesser extent. Tuberculous pneumonia is an overwhelming lung infection and extremely dangerous unless treated early.