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.

Virus Eradication, Extinction, and Elimination Explained

Jamestown Canyon Virus: An Emerging Arboviral Threat in Temperate Climates

What is a Viral Mutation?

What are Viral Clades?

Virus Origins

What is Vertical Transmission?

Human Diseases Caused by Viruses

Virus Infection in Other Species

Virus Uses in Virology

Are Viruses a Lifeform?

What is the Difference Between Bacteria and Viruses?

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What are Filoviruses?

Antiviral Immunity and COVID-19

Virus Microbiology

Virus Purification Methods

What Are Giant Viruses?

Virus History

Virus Classification

Latest Virus News and Research

New strategy harnesses pre-existing antiviral immunity to boost anti-tumor responses

Because many different types of cancer cells overexpress programmed death-ligand 1 (PD-L1), this cell surface protein is a major target of cancer immunotherapy.

11 Feb 2026

One in five US women prefer at-home HPV screening

National data shows women who experience healthcare discrimination favor at-home HPV testing, raising questions about trust and access in screening guidelines.

11 Feb 2026

Study suggests shingles vaccine may help lower Alzheimer’s and dementia risk

A large observational electronic health record study found that older adults receiving the recombinant zoster vaccine showed substantially lower rates of diagnosed dementia compared with matched unvaccinated individuals. The association persisted after multiple sensitivity analyses, although causality remains unproven and longer follow-up is required given the long latency of dementia.

10 Feb 2026

Parvovirus infection disrupts nucleolar structure and cellular balance

Research at the University of Jyväskylä (Finland) reveals that autonomous parvoviruses, such as canine parvovirus, are highly capable of affecting the internal balance of the nucleolus.

10 Feb 2026

Choroid plexus enlargement in Long COVID signals cognitive risk

The increased size of, and lesser blood supply to, a key brain structure in patients with Long COVID tracks with known blood markers of Alzheimer's disease and greater levels of dementia, a new study finds.

10 Feb 2026

Preexisting flu immunity may offer baseline protection against avian influenza

Are seasonal flu antibodies also effective against avian flu? A team from the University of Geneva (UNIGE) has shown that a specific type of antibody associated with the former virus—already present throughout the population—may offer baseline protection against the latter.

10 Feb 2026

Influenza viruses can directly impair heart function

Mount Sinai researchers have identified a cellular mechanism linking infections from influenza A viruses (IAVs) to cardiovascular disease, providing critical insights on how influenza can damage the heart and increase the risk of a heart attack or other major cardiovascular event.

9 Feb 2026

Menstrual blood HPV testing accurately detects cervical precancer

A study reveals menstrual blood can effectively screen for HPV, matching clinician-collected samples in accuracy, enhancing cervical cancer detection globally.

9 Feb 2026

CRISPR gene-drive technology reverses antibiotic resistance in bacteria

Antibiotic resistance (AR) has steadily accelerated in recent years to become a global health crisis. As deadly bacteria evolve new ways to elude drug treatments for a variety of illnesses, a growing number of "superbugs" have emerged, ramping up estimates of more than 10 million worldwide deaths per year by 2050.

7 Feb 2026

Binghamton University receives $2.5 million to develop a next-generation avian flu vaccine

Outbreaks of avian flu at U.S. poultry farms led to more than $1.5 billion in losses over the last two years and drove egg prices to all-time highs in 2025.

6 Feb 2026

New DNA-based vaccine scaffolds boost targeted immune responses to HIV

One of the biggest hurdles in developing an HIV vaccine is coaxing the body to produce the right kind of immune cells and antibodies. In most vaccines, HIV proteins are attached to a larger protein scaffolding that mimics a virus.

6 Feb 2026

Griffith researchers on the cusp of new vaccine to prevent chikungunya

Griffith University researchers are on the cusp of a new vaccine to prevent chikungunya, a global health threat which attacks human joint tissue.

6 Feb 2026

Enhanced natural killer cells show promise for HIV remission

More than 30 million people with HIV must take antiretroviral therapy (ART) medications daily to keep the virus under control, according to the Joint United Nations Programme on HIV/AIDS (UNAIDS).

5 Feb 2026

Weak governance hinders One Health outbreak response in Africa

Across Africa, One Health is endorsed at the top but often breaks down where outbreaks start, writes Albert Ansah.

5 Feb 2026

Study reveals evidence of silent mpox exposure in healthy Nigerians

New evidence suggests that mpox may be circulating quietly among healthy Nigerians, with some infections occurring without the symptoms that typically trigger detection by health authorities.

5 Feb 2026

Influenza D virus and canine coronavirus pose human risks

Two emerging pathogens with animal origins - influenza D virus and canine coronavirus - have so far been quietly flying under the radar, but researchers warn conditions are ripe for the viruses to spread more widely among humans.

5 Feb 2026

EBV-linked killer T cells implicated in multiple sclerosis

Researchers at UC San Francisco have uncovered a new clue to how Epstein-Barr virus (EBV) could contribute to multiple sclerosis (MS), a chronic autoimmune disease that affects nearly one million Americans.

5 Feb 2026

Breakthrough enables continuous laboratory growth of human norovirus

Researchers at Baylor College of Medicine report in Science Advances a breakthrough in human norovirus (HuNoV) research.

4 Feb 2026

Why did influenza fail to spread in a crowded indoor setting?

The EMIT-2 trial shows zero influenza transmission despite ideal conditions, suggesting a perfect storm is needed for the virus to spread effectively.

4 Feb 2026

Herpes virus infection softens cell nuclei through internal mechanical changes

A recent international research project has used advanced microscopy techniques and computational modeling to discover why virus infection changes the nuclear structures and biomechanical forces affecting the nucleus.

3 Feb 2026