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

See more featured articles »

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

The chicken and egg problem of fighting another flu pandemic

Even a peep of news about a new flu pandemic is enough to set scientists clucking about eggs.

31 May 2024

After grilling an NIH scientist over covid emails, Congress turns to Anthony Fauci

Former National Institutes of Health official Anthony Fauci has faced many hostile questions from members of Congress, but when he appears before a House panel on Monday, he'll have something new to answer for: a trove of incendiary emails written by one of his closest advisers.

31 May 2024

COVID-19 associated with higher risk of erectile dysfunction

Men previously diagnosed with COVID-19 are at a greater risk of developing new-onset erectile dysfunction.

31 May 2024

Engineered immunogens show promise in inducing HIV broadly neutralizing antibodies

Using a combination of cutting-edge immunologic technologies, researchers have successfully stimulated animals' immune systems to induce rare precursor B cells of a class of HIV broadly neutralizing antibodies (bNAbs).

30 May 2024

Three-year study shows lingering effects of COVID-19

New findings on long COVID -; long-term effects on health experienced by many who have had COVID-19 -; present a good-news, bad-news situation, according to a study at Washington University School of Medicine in St. Louis and the Veterans Affairs St. Louis Health Care system.

30 May 2024

Inexpensive “duckbill” N95 becomes the champion in COVID-19 mask effectiveness

In a head-to-head comparison of masks worn by people with active COVID-19, the inexpensive "duckbill" N95 came out on top, stopping 98% of COVID-19 particles in the breath of infected people from escaping into the air.

30 May 2024

Advancing protein structure prediction with quantum computing

Researchers from Cleveland Clinic and IBM recently published findings in the Journal of Chemical Theory and Computation that could lay the groundwork for applying quantum computing methods to protein structure prediction.

30 May 2024

New antibody shows promise as universal weapon against COVID-19 variants

SARS-CoV-2, the virus that causes COVID-19 disease, continues to evolve and evade current vaccine and therapeutic interventions.

29 May 2024

Foam-based delivery system could revolutionize gene therapies

Foam mixed with medications is already used to treat conditions such as varicose veins, hemorrhoids, wounds on the skin and even hair loss.

29 May 2024

Surface-enhanced raman spectroscopy for precise diagnosis of infections

Every year, medical diagnostics are getting better and better thanks to the tremendous development of new methods that enable the precise detection of the many different molecules present in biological fluids during an infection.

29 May 2024

Vaccination remains crucial for preventing avian influenza spread, says study

Vaccination remains the most effective strategy for avian influenza prevention and control in humans, despite varying vaccine efficacy across strains.

29 May 2024

Addressing local dynamics in rubella vaccination policy

When public health officials make policies about when and how vaccination programs are implemented, they must weigh the benefits and risks of how infectious diseases spread throughout the country.

29 May 2024

Farmworkers face high-risk exposures to bird flu, but testing isn’t reaching them

Farmworkers face some of the most intense exposures to the bird flu virus, but advocates say many of them would lack resources to fall back on if they became ill.

29 May 2024

Evaluating the efficacy of harmol in treating herpes simplex virus-induced keratitis

The antiviral efficacy and therapeutic potential of harmol in treating herpes simplex virus type 1 (HSV-1) induced keratitis

29 May 2024

Assessing the effects of COVID-19 on breast cancer screening rates

Breast cancer is the second most common cancer among women in the U.S. Early detection of the disease through screening can greatly improve the chances of successful treatment and is an essential preventive service in primary care.

28 May 2024

Understanding the link between EBV-infected B cells and multiple sclerosis

The Wistar Institute's Paul M. Lieberman, Ph.D., and lab team led by senior staff scientist and first author, Samantha Soldan, Ph.D., have demonstrated how B cells infected with the Epstein-Barr virus (EBV) can contribute to a pathogenic, inflammatory phenotype that contributes to multiple sclerosis (MS); the group has also shown how these problematic B cells can be selectively targeted in a way that reduces the damaging autoimmune response of multiple sclerosis.

28 May 2024

Study shows enforced masking on long flights prevents SARS-CoV-2 transmission

A recent study reveals that longer flights without enforced masking significantly increase the risk of SARS-CoV-2 transmission, while enforced masking on long-haul flights effectively prevents in-flight transmission. The findings underscore the importance of mask enforcement in reducing COVID-19 spread on aircraft.

28 May 2024