Dec 17, 2025 · Virus, infectious agent of small size and simple composition that can multiply only in living cells of animals, plants, or bacteria. Viruses possess unique infective properties and …

1 day ago · A virus is an infectious agent that occupies a place near the boundary between the living and the nonliving.

Viruses are small germs that have to infect a host — like humans, animals, plants — to reproduce. Learn more about types of viruses and how they work.

Apr 12, 2025 · They are among the tiniest entities in the biological universe, yet their presence has shaped the course of life on Earth for billions of years. They ride on the edge of life and …

Oct 19, 2023 · Viruses are tiny infectious agents that invade host cells and cause disease. Although they are harmful, viruses also have interesting technological potential.

Transmission is the passing of a virus from one host to another. The mechanism by which a virus is transmitted depends on several things, including which organisms the virus is able to infect, …

Jun 26, 2024 · A virus is the smallest type of parasite to exist and is typically within the size range of 0.02 to 0.3 micrometers (μm) in size; however, some viruses can be as large as 1 μm. …