There are many types of germs that can caurse pneumonia
(infection in the lungs).
They are found in the dirt or air, on skin, in the nose or mouth. When someone coughs, they spread their germs in a fine mist around them. Pneumonia germs usually start in the nose, throat or eyes. If the body fights the germ it may just cause a "cold" but if the germ "wins" and spreads, it can lead to "pneumonia".