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

Machine learning uncovers promising drug leads against human enterovirus 71

Artificial intelligence algorithms have now been combined with traditional laboratory methods to uncover promising drug leads against human enterovirus 71 (EV71), the pathogen behind most cases of hand, foot and mouth disease.

29 Apr 2025

Measles makes a deadly comeback in Europe as vaccine gaps widen

In 2024, measles cases in Europe soared to the highest levels in decades, with over 35,000 reported cases, 87% from Romania alone. Most affected were unvaccinated children, revealing critical immunity gaps and suboptimal vaccination coverage across the EU/EEA.

29 Apr 2025

Celebrating 25 years of GOARN's global health impact

The Global Outbreak Alert and Response Network (GOARN), an initiative coordinated by the World Health Organization (WHO), marks its 25th anniversary today.

29 Apr 2025

Global Virus Network urges action to prevent H5N1 pandemic

Today, the Global Virus Network (GVN), representing eminent human and animal virologists from 80+ Centers of Excellence and Affiliates in 40+ countries, published a comprehensive analysis and call-to-action in The Lancet Regional Health-Americas on the North American avian influenza virus, or H5N1, outbreak. The GVN calls on world governments to address the threat of H5N1 avian influenza by enhancing surveillance, implementing biosecurity measures, and preparing for potential human-to-human transmission.

29 Apr 2025

Influenza virus hijacks human gene regulator to evade immune system

The influenza virus manipulates the body's gene regulation system to accelerate its own spread, according to researchers at the University of Gothenburg.

28 Apr 2025

Immune evasion found in early stages of HPV-related anogenital lesions

A new research paper was published in Oncotarget, Volume 16, on April 24, 2025, titled "PD-L1 and FOXP3 expression in high-grade squamous intraepithelial lesions of the anogenital region."

28 Apr 2025

Scientists say global conditions are ripe for a yellow fever pandemic

A new study in npj Viruses warns that global trends like urbanization, travel, and mosquito spread are amplifying the risk of yellow fever virus (YFV) expansion into the Asia-Pacific. Researchers caution that the conditions for a devastating YF pandemic are now more favorable than ever.

27 Apr 2025

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