Virus | Definition, Structure, & Facts | Britannica
WEBApr 12, 2024 · 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 thus often cause disease in host organisms. Learn about the history, types, and features of viruses.
Virus - Wikipedia
WEBA virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity.
Intro to viruses (article) | Viruses | Khan Academy
WEBKey points: A virus is an infectious particle that reproduces by "commandeering" a host cell and using its machinery to make more viruses. A virus is made up of a DNA or RNA genome inside a protein shell called a capsid. Some viruses have an external membrane envelope. Viruses are very diverse.
Coronavirus - World Health Organization (WHO)
WEB5 days ago · Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus. Most people infected with the virus will experience mild to moderate respiratory illness and recover without requiring special treatment. However, some will become seriously ill and require medical attention.
Viruses: Definition, Types, Characteristics & Facts - Cleveland Clinic
WEBViruses are small germs (pathogens) that can infect you and make you sick. They can infect humans, plants, animals, bacteria and fungi. Each one infects only specific types of hosts. Viral infections in humans can cause no symptoms or make you extremely ill. Types of diseases they can cause include:
Viruses - National Geographic Society
WEBOct 19, 2023 · noun. pathogenic agent that lives and multiplies in a living cell. Viruses are tiny infectious agents that invade host cells and cause disease. Although they are harmful, viruses also have interesting technological potential.
Viruses: What are they, and what do they do? - Medical News Today
WEBApr 21, 2023 · Summary. Viruses are microscopic particles that are present in animals, plants, and other living organisms. They can sometimes cause diseases, such as the flu and COVID-19. Viruses are...
What is a virus? How do they spread? How do they make us sick?
WEBMar 13, 2020 · Once a person is infected with a virus, their body becomes a reservoir of virus particles which can be released in bodily fluids – such as by coughing and sneezing – or by shedding skin or in ...
virus | Learn Science at Scitable - Nature
WEBA virus is an infectious agent that can only replicate within a host organism. Viruses can infect a variety of living organisms, including bacteria, plants, and animals. Viruses are so small that ...
Virus facts and information - National Geographic
WEBFeb 22, 2019 · Inside their cellular hosts, viruses can create an enormous number of copies and spread the infection to other cells. For example, if you get the flu, your body will be riddled with some hundred ...