Which of the following diseases is/are caused by viruses?
All the above
A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to microorganisms. Example:
Smallpox is caused by the Variola virus.
Common cold is caused by different viruses.
AIDS is caused by Human Immunodeficiency Virus (HIV).