There are actually several different types of pneumonia, each with a different cause.
- Viral pneumonia - caused by a viral infection
- Bacterial pneumonia - caused by a viral infection. Usually more dangerous than viral pneumonia
- Fungal pneumonia - rare form of pneumonia with a high mortality rate. Caused by a fungal infection
- Parasitic pneumonia - caused by infection with parasitic organisms, such as roundworms
- Chemical pneumonia - Not a "true" pneumonia, it is caused by aspirating an irritating chemical