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

Virus Microbiology

Human Diseases Caused by Viruses

Jamestown Canyon Virus: An Emerging Arboviral Threat in Temperate Climates

What Are Giant Viruses?

What are Filoviruses?

Are Viruses a Lifeform?

What are Viral Clades?

Virus Infection in Other Species

What is the Difference Between Bacteria and Viruses?

Virus Classification

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What is a Viral Mutation?

Virus Purification Methods

Antiviral Immunity and COVID-19

Virus Origins

Virus Uses in Virology

What is Vertical Transmission?

Virus History

Latest Virus News and Research

How the aging gastrointestinal tract drives age-related cognitive decline

We become forgetful as we age. This is often seen as a universal truth, but in fact it is far from universal: some people remain incredibly sharp at 100 years old, while others experience memory loss starting in middle age.

11 Mar 2026

Prior flu exposure may weaken the immune response to other strains

Prior exposure to one strain of influenza virus may weaken children's ability to mount an effective antibody response against their subsequent exposure to a different flu strain, according to a study led by Weill Cornell Medicine investigators.

11 Mar 2026

Marburg virus enters human cells far more efficiently than Ebola

In a new study published in Nature, University of Minnesota researchers found that the Marburg virus, one of the world's deadliest pathogens with an average 73% fatality rate, is unusually efficient at getting inside human cells.

11 Mar 2026

Severe COVID and flu infections increase risk of lung cancer

Severe COVID-19 and influenza infections prime the lungs for cancer and can accelerate the disease's development, but vaccination heads off those harmful effects, new research from UVA Health's Beirne B. Carter Center for Immunology Research and UVA Comprehensive Cancer Center indicates.

11 Mar 2026

DNA origami vaccine platform shows promise against multiple infectious viruses

The COVID-19 pandemic brought messenger RNA (mRNA) vaccines to the forefront of global health care. After their clinical trial stages, the first COVID-19 mRNA vaccine was administered on 8 December 2020 and mathematical models suggest that mRNA vaccines prevented at least 14.4 million deaths from COVID-19 in the first year alone.

11 Mar 2026

EVA1A regulates fatty acid transporter CD36 in fatty liver disease

Metabolic Dysfunction-Associated Steatotic Liver Disease（MASLD） is characterized by excessive accumulation of lipids in hepatocytes and is closely associated with the rapid rise in insulin resistance, obesity, and diabetes prevalence, making it one of the most common chronic liver diseases worldwide.

9 Mar 2026

Researchers validate Mpox antibody test during outbreak in Rwanda

An antibody test for the infectious disease Mpox was successfully developed during the new clade 1b outbreak in Rwanda, the first time that an assay of its kind has been validated within this setting.

9 Mar 2026

Most pandemic viruses show little adaptation before infecting humans

A new University of California San Diego study published in Cell challenges a long-standing assumption about how animal viruses become capable of sparking human epidemics and pandemics.

9 Mar 2026

How somatic mutations shape disease and reveal new drug targets

Researchers reviewed how somatic mutations accumulate in normal and diseased tissues, showing that natural selection can expand clones that influence disease risk, tissue adaptation, or cellular resilience. The study proposes somatic genomics as a powerful strategy to uncover disease mechanisms and identify new therapeutic targets across multiple conditions.

8 Mar 2026

Scientists identify ANKIB1 as key regulator of innate immune signaling

Innate immune sensors – known as pattern recognition receptors (PRRs) – detect specific molecular components of bacterial or viral intruders.

6 Mar 2026

Disrupted iron levels after SARS-CoV-2 infection may trigger long COVID

Problems with iron levels in the blood and the body's ability to regulate this important nutrient as a result of SARS-CoV-2 infection could be a key trigger for long COVID, new research has discovered.

6 Mar 2026

Single dose of CAR-astrocyte therapy halves amyloid levels in mice brains

The new generation of Alzheimer's disease drugs - the first proven to change the course of the disease - typically extend independent living for patients by 10 months.

6 Mar 2026

Scientists discover how herpes simplex virus softens cells to multiply faster

Herpes simplex virus partially liquifies the tightly packed, gel-like interior of human cell nuclei to copy itself faster, a new study shows.

6 Mar 2026

Spatial intelligence platform supports health policy decisions aimed at ending HIV

INCLIVA Healthcare Research Institute-University Clinical Hospital of Valencia, the Universitat Politècnica de València - through its VRAIN Institute, the Valencia Anti-AIDS Committee and the Centre for Epidemiological Studies on Sexually Transmitted Infections and AIDS in Catalonia (CEEISCAT) have joined forces to develop a spatial intelligence platform to support health policy decisions aimed at optimizing the prevention of human immunodeficiency virus (HIV) and accelerating its early diagnosis.

5 Mar 2026

Researchers identify immune markers linked to cognitive decline after viral infections

What impact does a viral infection have on our memory, attention, and concentration? The COVID-19 pandemic has reignited interest in this question, which has now been extended to other infections such as HIV, herpes, and hepatitis.

5 Mar 2026

Long COVID taste loss tied to reduced expression of key taste genes

The study identifies molecular changes in taste receptor cells as a potential cause of persistent taste dysfunction in long COVID-19, impacting quality of life.

5 Mar 2026

Why measles remains one of the most contagious viral diseases worldwide

This review synthesizes current evidence on measles virus biology, immune responses, complications, treatments, and prevention strategies. It highlights how measles can suppress immune memory, increasing susceptibility to other infections, and underscores vaccination as the most effective control measure.

4 Mar 2026

Periodontal bacteria trigger bone density reduction via the gut

Periodontitis, a chronic inflammatory disease of the gums, affects hundreds of millions of people worldwide and is increasingly linked to systemic disorders beyond the oral cavity.

4 Mar 2026

Study uncovers a biological cause for persistent taste loss after COVID-19

Some individuals have experienced a loss of taste long after a COVID-19 infection has subsided. Researchers from the Swedish University of Agricultural Sciences, Uppsala University and the University of Colorado have now shown that this may be due to a disruption in taste cells that would otherwise give rise to experiences of sweet, bitter or umami.

4 Mar 2026

Natural fungal supplement strengthens vaccine protection without increasing side effects

Researchers at University California San Diego School of Medicine have found that a natural fungal supplement taken at the time of COVID-19 vaccination reduced short-term vaccine side effects and helped antibodies - the body's natural immune defenders - last longer in people who had not previously been exposed to the virus.

4 Mar 2026