any of various poisonous living things, smaller that bacteria, causing the spread of infectious disease
bacterium, bug
Cases of word usage
1) a disease of the skin with blisters, especially on the lips, caused by a virus (herpes)
2) Human Immunodeficiency Virus (the virus that is present in a person who may suffer from AIDS) (HIV)
3) a substance containing a virus or bacteria, used to protect a person from disease by encouraging antibodies (vaccine)
