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.
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.
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: 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...
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)
WebApr 18, 2024 · 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 - 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.
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 ...
Structure and features of viruses | Britannica
Webvirus, Microscopic, simple infectious agent that can multiply only in living cells of animals, plants, or bacteria. Viruses are much smaller than bacteria and consist of a single- or double-stranded nucleic acid (DNA or RNA ) surrounded by a protein shell called a capsid; some viruses also have an outer envelope composed of lipid s and …
Overview of Viral Infections - The Merck Manuals
WebA viral infection is a sickness caused by a virus. Viruses can get into your body through breathing air (for example, the virus that causes COVID-19), having sex, touching something with viruses on it, or being bitten by a bug such as a mosquito or tick
Skip to content