Receptors on the cell surface are key to whether a virus is successful

Flu viruses use special proteins to invade and spread in the body

Influenza viruses carry two key surface proteins: hemagglutinin (H), which lets them enter cells, and neuraminidase (N), which helps them escape and spread. These proteins are the basis for the names of flu subtypes like H1N1 and H3N2

Computer viruses' hijacking abilities led them to be named after biological viruses

Just as their counterparts infect cells and take control of cellular processes to replicate endlessly, computer viruses cannot replicate on their own and must copy their code into host software before duplicating when the program or file is opened. The term "virus" comes from the Latin word for "venom."

Bats are uniquely suited to act as reservoirs of viruses.

Some of the deadliest diseases to jump from animals to humans originate in bat species. This rich visualization explores the diversity of bats and the factors that make them efficient vectors for harboring and transmitting disease, from their long lifespans to their migration patterns.

Explore 3D models of some of the most dangerous viruses, allowing us to understand these and other pathogens in new ways.

Every virus is classified into 7 groups based on genetic differences

Viruses infecting humans have been named based on symptoms ("chickenpox") or the location or animal in which they were first discovered ("Bolivian Haemorrhagic Fever" and "Monkeypox"). For clarity among scientists and to reduce stigma, virologists classify the 15,000 known viruses (270 of which infect humans) by their basic genetic material.

Some viruses evade detection by altering their own code or hiding in Microsoft Office

Computer viruses are often classified by how they spread or which files they infect, with the oldest ones—boot sector viruses—targeting systems that are active when a computer is turned on. Macros—custom codes in office productivity programs authored to automate tasks—spawned their own class of viruses.

Bacteriophages—viruses that infect bacteria before multiplying within them—exist on Earth in numbers greater than all other living organisms combined.

CRISPR-Cas systems act as genetic memory banks for defending bacterial cells

When viruses called phages inject DNA into bacteria, some bacterial species store bits of this DNA in their own genomes. This allows them to recognize and destroy the same virus if it attacks again.

How bitter taste receptors help guard against infection

Receptors for "bitter" tastes evolved to detect potentially harmful plant chemicals, such as nicotine. The receptors also trigger bacteria-fighting responses, including waving hairlike projections to bat away bacteria, ordering the release of bacteria-killing nitric oxide, and calling for antimicrobial protein reinforcements.

Understanding R0, a measure of how contagious a pathogen is

The R0 value is a basic measure of how many people an infected person will transmit a pathogen to, on average. If R0 is less than 1, transmission dies out; if greater than 1, an outbreak is likely. Measles has one of the highest known R0 values at almost 18, meaning that after four transmission steps, more than 100,000 people could be infected.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

The seven viruses that cause human cancers

Certain viruses have been linked to the development of human cancers. These viruses account for up to 20% of cancers worldwide, causing cancer by interacting with host proteins, proliferating within weak immune systems, and commandeering susceptible human cells. Unlike other viruses, human tumor viruses don't kill host cells, allowing them to establish persistent infections. The seven viruses include the Epstein-Barr Virus, the Human Papillomaviruses, and more.

Vector-borne diseases kill more than 700,000 people globally each year—and are growing

The diseases with the greatest potential to spread widely aren't the ones that quickly kill human hosts. Instead, the best hosts or reservoirs for vector-borne diseases would be chronically ill over the long term, increasing the likelihood that the pathogen could be transmitted to others.

Modern antivirus software searches for malicious behavior alongside malicious code

The first viral infections were identified by comparing the computer code of programs and files with a database of known virus codes, a method known as signature detection. The ongoing creation of new malware made databases continuously outdated, leading to the development of systems that detect patterns consistent with known viral activity.

The gut microbiome's community of viruses is collectively known as the virome, but most of its viruses remain unidentified.

These cells 'taste' danger, trigger immune responses

Taste receptor-coated tuft cells are found throughout the body, where they communicate with and take part in a growing list of biological processes. In the intestines, these taste receptor-studded cells can sense byproducts of parasite metabolisms. This causes the taste receptors to release chemicals that alert the immune system, order nearby goblet cells to produce mucus, and trigger muscle contractions in attempts to launch the parasites from the intestines.

Bats have evolved to carry viruses without getting sick

Bats—the likely animal reservoir for diseases including Ebola and coronavirus—tolerate viruses without getting sick. The secret lies in evolutionary adaptations allowing bats to become the world’s only flying mammal and to thrive under immense physiological stressors.

The R0 value is how epidemiologists quantify disease contagiousness

The basic reproduction number indicates the average number of people a person with a disease will infect. Measles is the most contagious disease, with an R0 of 12-18, though vaccines have significantly reduced the number of susceptible individuals.

Robins are a major host for West Nile in North America, even though other species more readily spread the disease.

Explore a 3D model of the influenza virus

This interactive 3D model reveals the influenza virus’s structure—its outer coat and spike proteins—and compares it with other well-known viruses, offering a clear view of how flu differs from pathogens like HIV or coronaviruses.

Up to 8% of the human genome consists of ancient viral DNA

Human endogenous retroviruses are remnants of infections that affected human primate ancestors millions of years ago and were passed on by infiltrating sperm and egg cells. Studies have shown that this DNA may play a role in immune responses and in placental formation.

Watch what the Ebola virus does inside the body in order to spread and survive.

Herd immunity works by slowing down viral transmission until a disease dies out.

See how the Pfizer-BioNTech vaccine's mRNA instructions teach your own cells to trigger an immune response against the coronavirus's spike protein.

Seven known types of coronaviruses have jumped from animals to humans

Coronaviruses, including SARS-CoV-2, belong to a large family of viruses characterized by their crown-like appearance under a microscope, due to spike proteins on their surface. While thousands are believed to exist in animals, only seven are known to have made the jump to humans.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

Roughly 1 in 5 cancers are caused by viruses

About 20% of cancers are caused by viruses, with seven specific oncoviruses causing between 10% and 15% of cancers worldwide. These include human papillomavirus and hepatitis B and C viruses, which can lead to diseases such as cervical and liver cancer. Understanding the mechanisms of these viruses is crucial for prevention and treatment strategies.

HIV sidelines your immune system by destroying T cells, eventually rendering the body unable to fight off even minor illnesses.

What are universal vaccines?

As viruses mutate and develop, vaccines have to adapt, leading to regular recommended injections like flu shots. Researchers are working to develop universal vaccines that aim to protect against multiple virus variants if not entire virus families. These vaccines work by creating broadly neutralizing antibodies (bnAbs) that target aspects of viruses that don't typically mutate and are integral to the virus' survival.

NASA worries about the reactivation of dormant viruses during missions—particularly the virus that causes shingles—because spaceflight suppresses the human immune system and elevates stress hormones, making it more challenging to stay healthy.

Increasing contact between humans and wild animals is driving zoonotic threats

Zoonotic diseases, which spread from animals to humans, present one of the most significant emerging threats worldwide. Scientists have identified around 200 viruses capable of infecting humans, and unfortunately, the number of such diseases are on the rise—at least 60% of all emerging infectious diseases are zoonotic in origin.

Before vaccines, there was 'variolation': what was it?

Before the technology behind vaccinations was discovered, some keen observers of medicine around the globe noticed how previous infections could impact future ones. Learn about the techniques early physicians used before they had vaccines.

HFMD can survive on surfaces for days at a time

That's why the virus can be transmitted via fomites—surfaces that have virus on them like doorknobs, kids toys, etc. These viruses are resilient—they are often even resistant to freezing (and are frequently stored at freezing temperatures in lab settings).

Learn how monoclonal antibodies, which mimic the body's antibodies, can fight diseases like Ebola.

Explore how cells respond to signals from their environment

In "Dropping Signals," users can drag stimuli, such as hormones and light, into various cellular environments to observe cellular responses. These include changing their shape, enabling the transport of chemicals into or out of the cell via the cell membrane, or dividing to compensate for surrounding damaged cells.

Creating malware requires more than knowledge of programming languages

Because computer viruses, worms, and other malicious software reside within a computer's operating system, which manages computer hardware and software, cybercriminals writing effective malicious code must understand how the OS manages input and output, permissions, memory, etc. Knowledge of credentials and network access also helps create malware that easily spreads.

The proteins and sugars on the surface of your blood cells determine your blood type.

A computer virus is a type of malware that self-replicates and spreads

Spread through emails, downloads, messaging services, and outdated software, viruses attach to programs, self-replicate, and infect other systems. They can delete files, steal data, and cause performance issues as they spread.

Small genetic changes that accumulate over time force flu vaccines to be updated regularly.

Gene therapy treats a disease by editing the disease's underlying DNA, replacing it with a functional variant.

View a list of simple ways you can avoid catching a computer virus

Because this type of malware requires human intervention, such as plugging an infected flash drive into a computer or downloading and running an infected file, the chance of infection can be greatly reduced by being cautious about unfamiliar emails, attachments, and links. Keeping systems up to date with the latest security fixes is also crucial.

Dispose of invading viruses while learning about the CRISPR immune system

In this free, easy-to-play game, defend the city of Bacterium by playing the role of Cris Perotein. As you play, you'll learn microbiology and the workings of the mechanisms that CRISPR uses to protect bacteria. (desktop recommended)

TIGR may supplement CRISPR by providing more refined DNA targeting

The tandem interspaced guide RNA is primarily found in viruses—unlike CRISPR, which is bacterial in origin—and is smaller than CRISPR, making it easier to deliver into cells. The TIGR-Tas system appears to read both sides of the DNA double helix and opens a smaller segment of DNA for repairs, improving the precision of single letter modification.

Different types of malware are categorized by how they spread or operate

Computer viruses require user interaction to execute a file and spread, whereas worms can self-replicate across systems without human intervention. Ransomware locks systems until a key is provided, spyware tracks and reports user activity to a third party, and trojans disguise various types of malware as legitimate software.

Major genetic shifts in flu viruses can spark global pandemics

Antigenic shift happens when two different influenza viruses infect the same host and swap genetic material. The result is a brand-new subtype of influenza which, if easily spread among people, can trigger a worldwide pandemic.

Animal-to-human pathogens constitute 75% of emerging infectious diseases

Zoonotic diseases encompass more than 200 diseases transmitted from animals to humans, wherein humans are usually accidental hosts. Ranging from rabies to HIV to monkeypox, this overview lists some of the most common viral threats.

Rosalind Franklin uncovered the molecular structure of the tobacco mosaic virus

Franklin's work revealed the role of ribonucleic acid in virus infectivity, contributing to a foundational understanding of genetics and virology. Her molecular model of the virus was featured as the centerpiece at the 1958 Brussels World's Fair.

How the 1918 pandemic spurred developments in virology and vaccines

This article provides an in-depth historical account of the 1918 Spanish Flu pandemic, including its impact on the global population and how its occurrence spurred significant advancements in the study of viruses—laying the groundwork for the...

Explore a technical look at the measles virus and its toll on humanity through the ages.

Humans have taste receptors throughout the body, including in the testes and lungs, but we don't taste what they detect because those areas lack taste buds.