Virus

A virus is a microscopic infectious agent that can reproduce only inside a host cell. Viruses infect all types of organisms: from animals and plants, to bacteria and archaea. Since the initial discovery of tobacco mosaic virus by Martinus Beijerinck in 1898, more than 5,000 types of virus have been described in detail, although most types of virus remain undiscovered. Viruses are ubiquitous, as they are found in almost every ecosystem on Earth, and are the most abundant type of biological entity on the planet. The study of viruses is known as virology, and is a branch of microbiology.

What is a Virus?

A virus is a small infectious agent that can only replicate inside the cells of another organism.

What are Viral Clades?

What is Vertical Transmission?

What is a Viral Mutation?

Virus Eradication, Extinction, and Elimination Explained

What Are Giant Viruses?

Jamestown Canyon Virus: An Emerging Arboviral Threat in Temperate Climates

What is the Difference Between Bacteria and Viruses?

Virus Origins

Virus Uses in Virology

Virus History

What are Filoviruses?

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Virus Purification Methods

Virus Microbiology

Virus Classification

Antiviral Immunity and COVID-19

Virus Infection in Other Species

Human Diseases Caused by Viruses

Are Viruses a Lifeform?

Latest Virus News and Research

New imaging method reveals nanodomains inside ALS-linked protein droplets

Inside the cell reside many tiny assembly factories and warehouses that gather together all of the proteins and RNAs-which carry out instructions from our DNA-that a living being needs.

26 Nov 2025

South Carolina’s measles outbreak shows chilling effect of vaccine misinformation

Near the back corner of the local library's parking lot, largely out of view from the main road, the South Carolina Department of Public Health opened a pop-up clinic in early November, offering free measles vaccines to adults and children.

26 Nov 2025

'Mental model' approach shown to reduce effects of misinformation about mRNA vaccines

Correcting misinformation after it has gone viral is a common way of informing the public that what they've encountered may be inaccurate, lack context, be unproven, or be demonstrably false.

24 Nov 2025

Study uncovers how a specific immune cell may contribute to HIV persistence

Researchers from the Institute of Human Virology (IHV) at the University of Maryland School of Medicine have discovered how a specific type of immune cell may contribute to the persistence of HIV infections.

24 Nov 2025

Study introduces cost-effective approach to analyze entire T-cell repertoire

Studying T cells, the immune cells most responsible for responding to infections and cancers, just received a significant boost in the form of a new technique from St. Jude Children's Research Hospital.

24 Nov 2025

New Cochrane reviews confirm the effectiveness of HPV vaccines in preventing cervical cancer

Two new Cochrane reviews show strong and consistent evidence that HPV vaccines are effective in preventing cervical cancer and pre-cancerous changes, especially when given to young people before they are exposed to the virus.

24 Nov 2025

Kennedy sharpens vaccine attacks, without scientific backing

As the federal government prepares for the next meeting of its Advisory Committee on Immunization Practices, Health and Human Services Secretary Robert F. Kennedy Jr. has intensified his attacks on aluminum vaccine components used in many shots to boost the body's immune response.

24 Nov 2025

Study finds GLP-1 drugs improve strength and reverse aging biology in mice

Researchers showed that GLP-1 receptor agonism counteracts aging across multiple organs in mice, improving strength and reversing molecular aging signatures without meaningful effects on body weight. These benefits depended largely on hypothalamic GLP-1R signaling and closely mirrored the anti-aging patterns produced by rapamycin.

23 Nov 2025

New sequencing method reveals how transposons move and shape the genome

Cornell researchers have found that a new DNA sequencing technology can be used to study how transposons move within and bind to the genome.

22 Nov 2025

Promising long-term vaccine for Crimean-Congo hemorrhagic fever developed

Crimean-Congo hemorrhagic fever (CCHF) is one of the world's most dangerous yet overlooked infectious diseases.

22 Nov 2025

Comprehensive antibody map reveals how SARS-CoV-2 mutations evade immunity

Researchers at the Icahn School of Medicine at Mount Sinai and collaborators have created the most comprehensive map to date showing how antibodies attach to the SARS-CoV-2 virus, which causes COVID-19, and how viral mutations weaken that attachment.

21 Nov 2025

Scientists identify cellular control points to tackle multiple viruses

Scientists were pleased when they learned more about how the common cold gains a foothold in the body, identifying key cellular checkpoints that are important targets of the virus.

21 Nov 2025

Pairing antiviral therapy with immune modulation restores lung repair in lethal Influenza

Recovery from deadly influenza infection may hinge on helping the lungs heal in addition to stopping the virus, according to a new study in mice, which shows that pairing modest antiviral therapies with immune modulation can restore damaged tissues and lung function, even after severe infection has taken hold.

20 Nov 2025