What is a Virus? Definition and examples

The term VIRUS has two meanings. It may refer to a computer program that infects computer systems, or an infectious agent that replicates inside the living cells of organisms.

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They Both Cause Illness

Viruses can cause illness either in living things, such as humans, or in computer systems, i.e., they can make us or computers sick.

In 2020, a pandemic began which was caused by a virus known as the coronavirus. It spread all over the world and killed millions of people.

A disease caused by a virus is a viral disease, as opposed to a bacterial or fungal disease.


No biological and computer viruses cannot reproduce on its own. Biological viruses need a host cell while computer viruses require documents or files.

Computer Virus – Malware

A computer virus is a type of malware. Malware is any software program that has been deliberately created to harm computer systems or manipulate them.

Malware gains unauthorized access into computer systems causing damage or disruption.

The term MALWARE comes from the beginning of the word MALicious and the second half of softWARE. There are many different types of malware, including trojans, adware, ransomware, spyware, viruses, rootkits, keyloggers, and worms.

Biology – Virus

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In the world of biology, viruses are tiny, microscopic particles that make animals (including humans) and plants ill.

Many human diseases are caused by viruses. AIDS, chicken pox, mumps, measles, the common cold, flu, herpes, rubella, viral hepatitis, and COVID are viral diseases.

According to the National Human Genome Research Institute in the US:

“A virus is an infectious microbe consisting of a segment of nucleic acid (either DNA or RNA) surrounded by a protein coat. A virus cannot replicate alone; instead, it must infect cells and use components of the host cell to make copies of itself.”

“Often, a virus ends up killing the host cell in the process, causing damage to the host organism.”

Video – What is a Virus