noun, plural vi·rus·es.
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Origin of virus
OTHER WORDS FROM virusvi·rus·like, adjectivean·ti·vi·rus, adjective
Words nearby virus
What is a virus?
Viruses are only 20 to 300 nanometers—so small that even microscopes can’t see them. Viruses are also very simple. They consist of a core made of DNA or RNA, a protein coat that surrounds the core, and sometimes an envelope that surrounds the core.
A virus can’t reproduce on its own. Instead, it will infect a living cell and force it to make more copies of the virus. When the virus does this, it stops the cell from whatever it was doing before and, eventually, kills the cell.
Viruses are infectious, meaning they often cause symptoms that allow fluids with copies of the virus to spread to other organisms. For example, if you have the flu and cough on another person, your virus-containing saliva and mucus will enter the other person’s body and allow the virus to infect their cells.
Because viruses remain inside living cells, it is often impossible to kill the virus without also killing the cell. Usually, your immune system is the only thing that can safely fight a virus.
Why is virus important?
Viruses are responsible for some of the most deadly, incurable diseases we have today. In 2019, a new type of coronavirus (a family of viruses that often cause respiratory illnesses) was the cause of a deadly disease known COVID-19 (short for coronavirus disease 2019), which became a worldwide pandemic.
Viruses have also been responsible for other serious diseases, such as HIV (short for human immunodeficiency virus), that causes AIDS, a disease in which the immune system gradually breaks down and often leads to cancer.
Because viruses are so hard to kill and some can make you very sick, we try to prevent viruses from infecting us in the first place. Washing your hands, not breathing on people, and staying home when you are sick with a virus all help prevent the virus from spreading.
Vaccines are used to train your immune system to better fight specific viruses. Sometimes, antiviral medications can interfere with the virus’s ability to take over a cell or treat the symptoms of the virus rather than attack the virus itself.
Did you know ... ?
The word virus is also used to describe malicious computer code that is designed to harm or infect computers in a similar way to how a biological virus infects living things.
What are real-life examples of virus?
This photo depicts an image of a virus.
Viruses cause many deadly diseases so people are never fans of them.
Q: Which antibiotic should you take to treat COVID at home?
Antibiotics kill bacteria; COVID is caused by a virus
Unnecessary antibiotics and/or steroids in non-hospitalized patients do more harm than good
— Faheem Younus, MD (@FaheemYounus) July 15, 2020
I swear every time I leave the house I pick up a new virus
— Pilgerz (@EveLily95) January 6, 2018
True or False?
Because viruses are hard to kill, we try to prevent them from spreading in the first place.
Example sentences from the Web for virus
By September 10, there was a 44 percent increase in the proportion of people over age 75 who have been diagnosed with the virus compared to the previous week.
These viruses circulate year-round in the tropics but are more common during the rainy season.COVID-19 may one day come and go like the flu, but we’re not there yet|Kate Baggaley|September 16, 2020|Popular Science
That is when Eckard Wimmer, a virologist at Stony Brook University, caused a sensation by creating infectious polio virus starting from only genetic instructions.Synthetic biologists have created a slow-growing version of the coronavirus to give as a vaccine|David Rotman|September 16, 2020|MIT Technology Review
“Once a cell is infected, it is completely taken over by the virus, producing an astonishing number of viruses,” Ehre says.Lung cell images show how intense a coronavirus infection can be|Jonathan Lambert|September 15, 2020|Science News
By April, waves of workers who debone chickens or carve up pork elbow-to-elbow with their co-workers were falling ill from the virus.Emails Show the Meatpacking Industry Drafted an Executive Order to Keep Plants Open|by Michael Grabell and Bernice Yeung|September 14, 2020|ProPublica
The vaccine is delivered through a “carrier virus” that causes a common cold in chimpanzees but does not affect humans.
He became delirious, his heartbeat grew ragged, his blood teemed with the virus, and his lungs, liver and kidneys began to fail.
By May 27, five people had succumbed to the virus and 16 more were infected.Jail Threats for Sierra Leone Ebola Victims’ Families|Abby Haglage|December 10, 2014|DAILY BEAST
The current FDA-approved measles vaccine consists of live but weakened measles virus that is injected into the arm.
The fact that the virus is still alive has sustained many safety concerns, both rational and irrational, about its use.
If there is neuritis from the virus it becomes intense and causes muscular contractions, paresis, and paralysis.Essays In Pastoral Medicine|Austin Malley
(p. 442) But it was the more poisonous virus of Secession which finally laid their proud city low.The Boys of '61|Charles Carleton Coffin.
The scientists of Sator knew that the virus was virulent; in fact, too virulent for its own good.
They knew that shortly after every Nansalian died, the virus, too, would be dead.
It killed the host every time, and the virus could not live outside a living cell.
British Dictionary definitions for virus
noun plural -ruses
Derived forms of virusvirus-like, adjective
Word Origin for virus
Medical definitions for virus (1 of 2)
n. pl. vi•rus•es
Medical definitions for virus (2 of 2)
Scientific definitions for virus
Other words from virusviral adjective
Cultural definitions for virus (1 of 3)
Microorganisms consisting of DNA and RNA molecules wrapped in a protective coating of proteins. Viruses are the most primitive form of life. They depend on other living cells for their reproduction and growth. (See under “Medicine and Health.”)
notes for virus
Cultural definitions for virus (2 of 3)
A minute organism that consists of a core of nucleic acid surrounded by protein. Viruses, which are so small that a special kind of microscope is needed to view them, can grow and reproduce only inside living cells. (See under “Life Sciences.”)
Cultural definitions for virus (3 of 3)
See computer virus.