- Virus and Worms are malwares(malicious software programs).

- Virus spread from one machine to another via physical contact(USB) or sharing(e-mails), replicates itself by modifying other computer programs and inserting its own code. It is same like biological virus, it require living hosts — such as people, plants or animals.   

- Worms burrow from one machine to another across a network to spread itself. Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.