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.

Human Diseases Caused by Viruses

What are Filoviruses?

Virus Microbiology

Virus Purification Methods

What is a Viral Mutation?

Virus Uses in Virology

Jamestown Canyon Virus: An Emerging Arboviral Threat in Temperate Climates

Virus Origins

What is Vertical Transmission?

Antiviral Immunity and COVID-19

Virus Infection in Other Species

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What is the Difference Between Bacteria and Viruses?

Virus History

What are Viral Clades?

Virus Classification

What Are Giant Viruses?

Virus Eradication, Extinction, and Elimination Explained

Are Viruses a Lifeform?

Latest Virus News and Research

Measles outbreaks may reveal more than gaps in vaccination

A commentary in Human Vaccines & Immunotherapeutics argues that measles outbreaks can serve as a sensitive indicator of weaknesses in vaccination coverage, surveillance, health equity, community trust, and broader immunization systems. The authors contend that pursuing measles eradication could also strengthen routine immunization, laboratory capacity, outbreak preparedness, and health-system resilience.

21 Sep 2026

New mRNA vaccine expands flu protection options for older adults

Every fall, millions of Americans heed the call to get their annual flu shot. Getting vaccinated reduces the risk of severe illness, hospitalization, and death from influenza.

20 Sep 2026

Mosquito excrement offers new way to detect circulating viruses

When public health researchers want to know whether diseases such as COVID-19 or polio are circulating in a community, they can look for genetic evidence in wastewater.

18 Sep 2026

HIV awareness emphasizes prevention, treatment and healthy aging

About 1.2 million people in the United States are living with HIV, or human immunodeficiency virus. Because of major advances in medical treatment and technology, people with HIV are living long, healthy lives.

18 Sep 2026

SARS-CoV-2 protein ORF8 drives macrophage infection and lung inflammation

In the sickest COVID-19 patients, the SARS-CoV-2 virus doesn't just cause severe damage by directly infecting airway cells.

18 Sep 2026

Adenine base editing slows neurodegeneration in hereditary motor neuron disease

A team of researchers led by Professor Haruhisa Inoue (Center for iPS Cell Research and Application, Kyoto University) and Professor Yuishin Izumi (Tokushima University) demonstrated that adenine base editing can correct a disease-causing genetic mutation and alleviate neurodegeneration in hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P), providing proof of concept for a precision gene therapy for inherited motor neuron diseases.

18 Sep 2026

Global Virus Network monitors spreading avian influenza in Australian mammals

The Global Virus Network (GVN) is closely monitoring detections of highly pathogenic avian influenza A (H5N1), commonly known as bird flu, in several mammal species in Australia as the virus continues to spread among birds and mammals worldwide.

18 Sep 2026

Chile becomes first South American nation to eliminate dog-transmitted rabies

Chile has become the first country in South America to receive the World Health Organization (WHO) validation for eliminating dog-transmitted rabies as a public health problem.

18 Sep 2026

Antibody therapy teaches the immune system to control HIV

There is no cure for HIV. While scientists have made considerable progress in controlling the infection, patients still must take daily antiretroviral medication for the rest of their lives.

18 Sep 2026

Persistent stigma creates barriers to modern HIV prevention methods

For decades, HIV (human immunodeficiency virus) has been surrounded by fear, misinformation and stigma.

18 Sep 2026

Eight-weekly HIV injections prove more effective than daily tablets for young people

Young people living with HIV manage their condition better when their antiretroviral therapy is given by injections every eight weeks, rather than in the form of daily tablets, according to the results of a trial in Africa led by UCL (University College London) researchers.

17 Sep 2026

New funding boosts data archive that tracks healthy aging environments

With an $11 million award from the National Institute on Aging, University of Michigan researchers will build and share national data that track how neighborhood conditions change over time, helping scientists study how local environments affect older adults' health.

17 Sep 2026

Innate immune system variations determine vaccine side effects

Redness and pain at the injection site, fever, fatigue or headaches: vaccines can cause side effects, but their frequency and severity vary considerably from person to person.

17 Sep 2026

Single-molecule imaging reveals nucleated growth mechanism of viral capsids

Oxford University researchers have captured the step-by-step assembly of individual virus-like particles, revealing how simple molecular interactions can reliably build these complex biological structures. The results have been published today (16 September) in Nature.

17 Sep 2026