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

Rare lung cell found to protect against COVID-19 death

A rare cell type in the lungs is essential to survival from the COVID-19 virus, a new study shows.

25 Apr 2025

Children with chronic conditions face higher RSV hospitalization risk

Young children with chronic conditions are more likely to be hospitalized for respiratory syncytial virus (RSV) than healthy children, according to a new study.

25 Apr 2025

Novel cancer immunotherapy approach could complement existing CAR-T treatments

Researchers in South Korea have proposed a novel cancer immunotherapy approach that could complement existing CAR-T (Chimeric Antigen Receptor T-cell) treatments.

24 Apr 2025

Shingles vaccine eligibility lowers dementia risk in older adults

A large quasi-experimental study in Australia found that adults eligible for free shingles vaccination based on their date of birth were significantly less likely to be diagnosed with dementia over a 7.4-year period. The findings reinforce previous results from Wales and suggest a potential preventive role for HZ vaccination.

24 Apr 2025

COVID-19 lowers sperm count and motility, new study confirms

SARS-CoV-2 infection is linked to significant declines in sperm quality, including reduced sperm count, motility, and increased DNA fragmentation, as shown in both cross-sectional and longitudinal observations.

24 Apr 2025

H5N1's evolutionary leap could undermine vaccines and heighten human infection risk

From egg prices to pet food recalls – and now, confirmation that another strain of bird flu has infected a large commercial flock of broiler chickens on a Mississippi farm – headlines are capturing escalating concern over H5N1's spread.

24 Apr 2025

New biosensor offers fast detection of H5N1 in farm air

As highly pathogenic H5N1 avian influenza continues to spread in the U.S., posing serious threats to dairy and poultry farms, both farmers and public health experts need better ways to monitor for infections, in real time, to mitigate and respond to outbreaks.

24 Apr 2025

Baloxavir marboxil shows promise in reducing household flu spread

One dose of the antiviral baloxavir marboxil lowers the chance of transmitting the influenza virus to family members by about 30%, according to research in the New England Journal of Medicine.

24 Apr 2025

Scientists develop promising new drug candidates against coronaviruses

A team at UC San Francisco and Gladstone Institutes has developed new drug candidates that show great promise against the virus that causes COVID-19 and potentially other coronaviruses that could cause future pandemics.

23 Apr 2025

One RSV shot cuts severe lung infections in older adults for three seasons, trial shows

A phase 3 trial involving nearly 25,000 older adults across 17 countries found that a single dose of the RSVPreF3 OA vaccine reduced RSV-related lower respiratory tract disease by 63% over three seasons. Protection remained substantial despite waning, with similar efficacy to a two-dose regimen and a favorable safety profile.

23 Apr 2025

San Antonio scientists use machine learning to identify potential treatments for deadly viruses

A team of San Antonio-based biomedical researchers trained a machine learning algorithm to identify more than two dozen viable treatments for diseases caused by zoonotic pathogens that can jump from animal hosts to infect humans.

23 Apr 2025

New vaccine targets sugar shield to protect against multiple coronaviruses

Sugar coatings aren't only for candies; they also help viruses, like the ones that cause COVID-19, hide from their hosts' immune system.

23 Apr 2025

Beckman Coulter Life Sciences transforms purification with the launch of the OptiMATE Gradient Maker

Beckman Coulter Life Sciences, a Danaher company and a global leader in laboratory automation and innovation, announces the launch of the OptiMATE Gradient Maker, a groundbreaking instrument designed to automate the process of density gradient ultracentrifugation (DGUC).

From Beckman Coulter Life Sciences - Flow Cytometry 22 Apr 2025

Interferon regulatory factor 8 identified as key driver of liver fat buildup in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is a hepatic metabolic syndrome resulting from lipid metabolic imbalance. Interferon regulatory factor 8 (IRF8) is well known for its roles in immune cell differentiation and tumor pathogenesis; however, its role in regulating glucose homeostasis and lipid metabolism remains unclear.

22 Apr 2025

Africa CDC and WHO strengthen mpox response with updated strategy

Africa CDC and WHO have updated their joint Continental Response Plan for the mpox emergency as the disease continues to affect new areas.

18 Apr 2025

Public ignorance and apathy towards bird flu could hinder preventive efforts

In an editorial in the American Journal of Public Health, a team led by researchers from the CUNY Graduate School of Public Health and Health Policy (CUNY SPH) say public ignorance and apathy towards bird flu (highly pathogenic avian influenza, or HPAI) could pose a serious obstacle to containing the virus and preventing a larger-scale public health crisis.

17 Apr 2025

Legal challenge puts ACA’s preventive health services in jeopardy

A study by the Stanford Prevention Policy Modeling Lab (PPML) finds that almost 30% of privately insured individuals in the United States, or nearly 40 million people, use at least one of the free preventive health services guaranteed under the Affordable Care Act (ACA).

17 Apr 2025

Vaccine trial shows promise for saving California condors from bird flu

Researchers evaluated the safety and immune response of a poultry-derived H5N1 avian influenza vaccine in black vultures and critically endangered California condors. The findings support the use of vaccination as a conservation tool against deadly avian flu outbreaks.

17 Apr 2025

Experimental bird flu vaccine offers strong protection in preclinical trials

A vaccine under development at the University at Buffalo has demonstrated complete protection in mice against a deadly variant of the virus that causes bird flu.

17 Apr 2025

Beyond Ivy League, RFK Jr.’s NIH slashed science funding across states that backed Trump

The National Institutes of Health's sweeping cuts of grants that fund scientific research are inflicting pain almost universally across the U.S., including in most states that backed President Donald Trump in the 2024 election.

17 Apr 2025