A pathogen is a foreign body, bacteria, or virus.
Pneumonia is an inflammation or infection of the lungs most commonly caused by a bacteria or virus. Pneumonia can also be caused by inhaling vomit or other foreign substances.
You can find names for viruses and bacteria in a medical health book. A good source is a book called Bacteria and Viruses by Leslie J. Lemaster.
Bacteria and virus
Smallpox was a virus.
virus
a bacteria. the bacteria that causes pneumonia is called pneumoniae.
Bacteria Virus
Viruses are (debatably) not alive while bacteria are; meaning they are smaller and require a living host to survive. Bacteria are killed with antibiotics, but viruses are not.
Virus
Virus
virus
Virus