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 is the Difference Between Bacteria and Viruses?

Virus History

Virus Origins

Virus Microbiology

Virus Classification

Virus Infection in Other Species

Human Diseases Caused by Viruses

Virus Uses in Virology

Virus Purification Methods

What are Filoviruses?

Antiviral Immunity and COVID-19

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What is Vertical Transmission?

What is a Viral Mutation?

What are Viral Clades?

Are Viruses a Lifeform?

What Are Giant Viruses?

Virus Eradication, Extinction, and Elimination Explained

Latest Virus News and Research

Small antibodies provide broad protection against SARS coronaviruses

Scientists have discovered a unique class of small antibodies that are strongly protective against a wide range of SARS coronaviruses, including SARS-CoV-1 and numerous early and recent SARS-CoV-2 variants.

14 Jun 2025

Research highlights the lasting impact of geographic labels in pandemic reporting

"China virus", the Chinese virus - at the start of the 2020 pandemic, you likely often encountered this epithet in the media.

13 Jun 2025

CDC staffing upheaval disrupts HIV projects and wastes money, researchers say

Dozens of HIV experts at the Centers for Disease Control and Prevention received emails on Wednesday revoking notices they received 10 weeks ago that laid them off.

13 Jun 2025

WHO warns of ORVO as outbreaks surge and health risks rise

Oropouche virus poses a growing public health risk, with recent outbreaks in Brazil and Cuba. The WHO report calls for urgent global preparedness measures.

13 Jun 2025

Kennedy’s HHS sent Congress ‘junk science’ to defend vaccine changes, experts say

A document the Department of Health and Human Services sent to lawmakers to support Secretary Robert F. Kennedy Jr.'s decision to change U.S. policy on covid vaccines cites scientific studies that are unpublished or under dispute and mischaracterizes others.

13 Jun 2025

AI and film animation tools lead to breakthrough in coronavirus drug discovery

About 30% of all respiratory tract infections are caused by coronaviruses, leading to widespread illnesses and, in some cases, to epidemic and even pandemic outbreaks, as we experienced with the COVID-19 pandemic.

13 Jun 2025

New CRISPR tool enables precise chemical modification of RNA in living cells

CRISPR-Cas13, a powerful RNA-targeting technology is gaining increasing attention as a next-generation gene therapy platform due to its precision and reduced side effects.

12 Jun 2025

Chikungunya vaccine could stop millions of infections worldwide, study finds

A landmark global modeling study reveals that more than 2.8 billion people in 104 countries are at risk of chikungunya, with up to 35 million infections annually. Strategic deployment of the IXCHIQ vaccine could prevent thousands of infections and deaths each year.

11 Jun 2025

Study reveals a unique vulnerability in melanoma patients with neurofibromin 1 mutations

Increased activity in a specific biological pathway may explain why many patients with a deadly form of skin cancer do not respond to the latest cancer treatments, a new study shows.

10 Jun 2025

Mental recovery after COVID lags behind physical recovery

New research finds that people with COVID-like symptoms returned to optimal physical well-being an average of three months after infection, but took up to nine months to return to top mental well-being.

10 Jun 2025

Early signs of breastfeeding failures after premature birth

A study on breastfeeding after premature birth identifies key factors affecting milk composition and volume, emphasizing the need for early support for mothers.

10 Jun 2025

Manganese-coordinated lipid nanoparticles boost VZV vaccine-induced T cell responses

Announcing a new article publication for Zoonoses journal. Because varicella zoster virus (VZV) infections are continually increasing, vaccine efficacy must be enhanced.

10 Jun 2025

Measles poses serious risks for pregnant people amid rising cases in Canada

Measles is on the rise in Canada and poses serious risks to pregnant people and their newborns, yet discussion about how to protect this vulnerable group is notably lacking.

9 Jun 2025

‘We dissent’: NIH workers protest Trump policies that ‘harm the health of Americans’

Hundreds of workers at the National Institutes of Health on Monday openly protested the Trump administration’s cuts to the agency and consequences for human lives, writing in a sharply worded letter that its actions are causing "a dramatic reduction in life-saving research."

9 Jun 2025

New COVID variant NB.1.8.1 spreads across continents amid calls for vigilance

The Global Virus Network (GVN) is closely monitoring the emergence of a newly identified SARS-CoV-2 variant, NB.1.8.1, a sublineage of the Omicron family. This variant was first identified in January 2025 and has rapidly spread across Asia and into other regions, including parts of the United States.

6 Jun 2025

In axing mRNA contract, Trump delivers another blow to US biosecurity, former officials say

The Trump administration's cancellation of $766 million in contracts to develop mRNA vaccines against potential pandemic flu viruses is the latest blow to national defense, former health security officials said.

6 Jun 2025

New technique creates multimeric aptamers for precision virus targeting

We have all heard of antibodies – proteins produced by our bodies to bind to viruses or bacteria, marking them for elimination by the immune system.

6 Jun 2025

Compact diagnostic platform enables rapid COVID-19 antibody testing from fingertip blood

Researchers from the Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences, along with multiple collaborators, have developed a compact diagnostic platform that can evaluate antibody protection against COVID-19 using only a single microliter of fingertip blood.

5 Jun 2025

Norovirus GII.17 overtakes GII.4 as the dominant strain in US outbreaks

Norovirus GII.17 has rapidly overtaken GII.4 as the leading cause of norovirus outbreaks in the United States between 2022 and 2025. This unprecedented shift signals an urgent need for continued genomic surveillance and preparedness for future outbreak trends.

4 Jun 2025

Researchers warn of bird flu survival in raw milk

The stability of H5N1 in unpasteurized milk poses potential health risks. Study findings emphasize the need for awareness among consumers and dairy workers.

4 Jun 2025