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

What is Vertical Transmission?

Are Viruses a Lifeform?

Virus Purification Methods

What is the Difference Between Bacteria and Viruses?

Virus Uses in Virology

Virus Origins

What is a Viral Mutation?

Virus Microbiology

What Are Giant Viruses?

Virus History

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Human Diseases Caused by Viruses

What are Filoviruses?

Virus Classification

Virus Infection in Other Species

Antiviral Immunity and COVID-19

Jamestown Canyon Virus: An Emerging Arboviral Threat in Temperate Climates

What are Viral Clades?

Latest Virus News and Research

Respiratory viruses awaken dormant breast cancer cells and raise relapse risk

Respiratory viruses such as influenza and COVID-19 can reactivate dormant breast cancer cells in the lungs, raising the risk of metastasis. The process is driven by IL-6–induced cell changes and immune suppression, with the highest recurrence risk soon after infection.

14 Aug 2025

GIPR signaling opens brain’s gate for GLP-1 weight-loss therapy

A Cell Metabolism study reveals that GIPR signaling in oligodendrocytes enhances brain access and weight-loss efficacy of GLP-1R agonists by increasing vascular permeability and targeting appetite-regulating neurons. This mechanism may explain why GIPR/GLP-1R co-agonists outperform single-agent therapies.

14 Aug 2025

Gene editing restores hearing and balance in adult mice with DFNA41 deafness

Zheng-Yi Chen, DPhil, associate scientist at the Eaton-Peabody Laboratories, and Ines and Fredrick Yeatts Chair in Otolaryngology, at Mass Eye and Ear, is the senior and co-corresponding author of a paper published in the Journal of Clinical Investigation, "Single Dose Genome Editing Therapy Rescues Auditory and Vestibular Functions in Adult Mice with DFNA41 Deafness."

14 Aug 2025

COVID-19 increases risk of asthma and sinusitis while vaccination offers protection

People who have had COVID-19 are at increased risk of developing certain inflammatory diseases of the airways, such as asthma, hay fever and chronic sinusitis.

14 Aug 2025

Rare immune mutation unlocks universal antiviral protection

For a few dozen people in the world, the downside of living with a rare immune condition comes with a surprising superpower-the ability to fight off all viruses.

14 Aug 2025

‘Alternative facts’ aren’t a reason to skip vaccines

President Donald Trump's administrations have been notorious for an array of "alternative facts" — ranging from the relatively minor (the size of inaugural crowds) to threats to U.S. democracy, such as who really won the 2020 election.

14 Aug 2025

Study shows economic benefits of continued COVID-19 vaccination

As the nation gears up for the rollout of an updated COVID-19 vaccine, a new study shows the economic benefits of continued broad vaccination in adults.

14 Aug 2025

New diagnostic tool offers rapid, low-cost blood test for multiple diseases

Researchers at Arizona State University have developed a breakthrough diagnostic tool that could transform how quickly and reliably we detect illnesses like COVID-19, Ebola, AIDS or Lyme disease. The test uses just a single drop of blood, costs a couple of dollars and delivers results in only 15 minutes.

13 Aug 2025

Rising human adaptive potential seen in 2.3.4.4b clade of H5N1

In recent years, there has been growing concern over the H5N1 influenza virus. It was first identified in birds three decades ago and has now gradually found its way to humans.

12 Aug 2025

Global Virus Network committed to the continued development of mRNA vaccines

The Global Virus Network (GVN), a coalition of leading human and animal virologists from 80+ Centers of Excellence and Affiliates in more than 40 countries dedicated to advancing pandemic preparedness, is unequivocally committed to the continued development and deployment of mRNA vaccines and the global scientific collaboration that makes such innovation possible.

12 Aug 2025

Synthetic sugar-coated nanoparticle blocks Covid-19 from infecting human cells

Groundbreaking research led by a Swansea University academic has revealed a synthetic glycosystem - a sugar-coated polymer nanoparticle - that can block Covid-19 from infecting human cells, reducing infection rates by nearly 99%.

11 Aug 2025

New biomarker may be the first specific and quantifiable indicator for confirming long COVID

Researchers from the Translational Genomics Research Institute (TGen), part of City of Hope, and the Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center have identified a potential biomarker for long COVID.

11 Aug 2025

How early immune challenges influence oral and systemic health in children

Once viewed only as infectious invaders, bacteria are now understood to play an important role in overall health.

8 Aug 2025

Revolutionizing therapeutic protein design with synthetic biology

In medicine and biotechnology, the ability to evolve proteins with new or improved functions is crucial, but current methods are often slow and laborious.

8 Aug 2025

New research pipeline fuels the development of universal vaccines

Most vaccines are designed to provide immunity against just one pathogen. Vaccines for chicken pox (caused by varicella-zoster virus) were only developed to fight that one disease, for example.

7 Aug 2025

Immune surveillance in children sheds light on virus rebound after COVID

The first paper from a multi-year clinical research study has been published in The Lancet Infectious Diseases: Dynamics of Endemic Virus Re-emergence in Children in the USA Following the COVID-19 Pandemic (2022-2023): A Longitudinal Immunoepidemiologic Surveillance Study and demonstrates how the approach can improve modeling to better predict future outbreaks.

7 Aug 2025

New toolkit supports hepatitis prevention and care in European prisons

The new toolkit is designed to support the implementation and scale-up of hepatitis B and C interventions in prisons across Europe.

6 Aug 2025

Starfish compound overcomes drug resistance in prostate cancer models

Researchers identified that triterpene glycosides from the starfish Solaster pacificus can kill drug-resistant prostate cancer cells in vitro by bypassing common resistance pathways. CuC1 showed synergy with existing chemotherapies, though with only moderate selectivity for cancer cells.

5 Aug 2025

Gfi1 regulates exhausted CD8+ T cells to improve cancer immunotherapy

Killer immune cells destroy cancer cells and cells infected by virus. These CD8+ T cells are activated after detection of viral infection or growth of "non-self" tumor cells.

5 Aug 2025

HIV trial points to semaglutide as a new anti-aging contender

Once-weekly semaglutide significantly slowed epigenetic aging in adults with HIV-associated lipohypertrophy, as measured by multiple DNA methylation clocks in a randomized controlled trial. These exploratory findings suggest GLP-1 receptor agonists could impact biological aging but require further validation in broader populations.

4 Aug 2025