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.

Antiviral Immunity and COVID-19

Virus History

Virus Purification Methods

Virus Classification

What Are Giant Viruses?

What is the Difference Between Bacteria and Viruses?

Virus Uses in Virology

Are Viruses a Lifeform?

Jamestown Canyon Virus: An Emerging Arboviral Threat in Temperate Climates

What is Vertical Transmission?

Virus Microbiology

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Human Diseases Caused by Viruses

Virus Eradication, Extinction, and Elimination Explained

What is a Viral Mutation?

What are Filoviruses?

What are Viral Clades?

Virus Infection in Other Species

Virus Origins

Latest Virus News and Research

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

Global Virus Network awards first pandemic preparedness research grants across four continents

The Global Virus Network (GVN) is pleased to announce that, for the first time, it is awarding pandemic preparedness research grants, totaling $160,000, to GVN scientists across four continents.

20 Nov 2025

Waning immunity and falling vaccination rates fuel pertussis outbreaks

Rates of pertussis, also known as whooping cough, are surging in Texas, Florida, California, Oregon, and other states and localities across the country.

20 Nov 2025

New AI investment aims to accelerate the search for an effective HIV vaccine

As of 2024, over 40 million people in the world are diagnosed with human immunodeficiency virus (HIV)-a chronic, life-threatening infection that remains one of the leading global causes of death.

18 Nov 2025

Harnessing a natural blood vessel molecule to develop broad mRNA antivirals

In a surprising discovery, a 'sticky molecule' that occurs naturally in our blood vessels could be both a culprit behind blood clots and organ failure during COVID and long COVID and the key to new treatments to counter COVID-related viruses.

18 Nov 2025

Muscle-driven gene therapy shows promise for protecting memory in Alzheimer’s

Alzheimer's disease (AD) is a devastating cause of memory loss and cognitive decline, for which no curative treatment is available.

18 Nov 2025

Gut immune cells follow an atypical pathway to provide long-lasting antiviral protection

A new study led by University of Toronto researchers has shown that immune cells in the gut follow an atypical pathway to produce antibodies that provide long-term protection against viruses.

17 Nov 2025

T cells drive vaccine effectiveness against porcine reproductive and respiratory syndrome virus

A new study shows that the effectiveness of current vaccines against porcine reproductive and respiratory syndrome virus (PRRSV) is due to the response of T cells against the disease, rather than the production of antibodies.

17 Nov 2025

Preparing for the respiratory virus season: A guide for families

As respiratory virus season begins, pediatric experts are preparing for an expected rise in cases of Respiratory Syncytial Virus (RSV), which can cause cold-like symptoms in most people but serious illness in infants and older adults.

17 Nov 2025

Wild birds found to be key drivers of H5N1 outbreak in North America

Since late 2021, a panzootic, or "a pandemic in animals," of highly pathogenic bird flu variant H5N1 has devastated wild birds, agriculture, and mammals.

14 Nov 2025

Conflicting advice on covid shots likely to ding already low vaccine rates, experts warn

More than three-quarters of American adults didn't get a covid shot last season, a figure that health care experts warn could rise this year amid new U.S. government recommendations.

14 Nov 2025

Study links common Epstein-Barr virus to autoimmune lupus

One of humanity's most ubiquitous infectious pathogens bears the blame for the chronic autoimmune condition called systemic lupus erythematosus or, colloquially, lupus, Stanford Medicine investigators and their colleagues have found.

12 Nov 2025

Nasal vaccine shows promise as a non-invasive treatment for cervical cancer

Cervical cancer, which affects the reproductive tract, is one of the most common cancers in women worldwide.

12 Nov 2025

Understanding thrombocytopenia in patients with portal hypertension and chronic liver disease

Chronic liver disease (CLD) and its advanced stage, cirrhosis, represent a significant global health burden, with portal hypertension (PH) being a primary driver of disease progression and decompensation.

12 Nov 2025

Tiny airborne plastics may facilitate virus spread

As plastic pollution worsens worldwide, scientists are uncovering a new and unsettling possibility. Tiny airborne fragments of plastic, known as micro- and nanoplastics, may do more than pollute the air we breathe.

11 Nov 2025

Green-synthesized nanoparticles enhance cidofovir's anticancer efficacy

In this study, led by Nahid Shahabadi from Razi University in Kermanshah, researchers developed an environmentally friendly approach to enhance the performance of cidofovir, a drug used to treat infections caused by DNA viruses. The work responds to the growing need for therapies that are safer, more effective, and better targeted.

10 Nov 2025