Roughly 1 in 5 cancers are caused by viruses

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.

The HPV vaccine reduces cervical cancer rates by 90% or more

Cervical cancer is the fourth most common cancer in women globally. Almost all cases (99%) are linked to infection with high-risk human papillomaviruses. However, cervical cancer is both treatable and preventable—and we may be able to prevent most cases through vaccination.

About 40% of cancer cases are linked to preventable risk factors

Maintaining a healthy weight, engaging in regular physical activity, and consuming a balanced diet can lower cancer risk. Research indicates that about 40% of US cancer cases are linked to preventable factors, including poor diet and inactivity. Understanding these mechanisms empowers individuals to adopt healthier lifestyles for cancer prevention.

Alcohol is responsible for 5% of cancer cases and 4% of cancer deaths in the US

Alcohol consumption is linked to at least eight different types of cancer, including liver, breast, and throat. The risk comes from ethanol, which turns into DNA-damaging acetaldehyde. Experts recommend limiting intake or quitting altogether to reduce long-term health risks.

There are hundreds of subtypes of cancer, making a universal cure nearly impossible

Cancer is an umbrella term for over 200 different diseases, each with its own subtypes, genetic mutations, and behaviors. This diversity means that a treatment effective for one cancer type or patient may be ineffective for others. Moreover, as tumors grow, their cells accumulate different mutations, creating subclones with unique characteristics.

Breast, prostate, and lung cancer are the most common forms of the disease

Close to 1.8 million cases of cancer are diagnosed each year in the US, with more than 600,000 deaths (about 0.2% of the total population). This visualization tool offers a searchable database of aggregate statistics on common cancers by gender, race, state, and other demographic information.

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.

Many cancers arise from genetic mutations inherited from your parents

These mutations may happen in response to environmental or lifestyle factors, or may be passed down through family members. Genetic testing can be important in catching certain family cancers early and ensuring patients receive the right treatment for their disease.

How does cancer spread through the body?

Cancer usually begins with one tumor, but it can spread to other organs if not removed. This video breaks down how cancer moves to these new areas and why some organs are more likely to get infected than others.

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.

Explore 3D models of some of the most dangerous viruses

Everyone has come in contact with common viruses—typically something like influenza (the common flu)—but sometimes they encounter more dangerous strains. While we're familiar with the symptoms that manifest, it wasn't until the advent of advanced microscopy that scientists could pin down the exact structure and behavior of various viruses.

See this diverse list of vector-borne diseases

Human illnesses caused by parasites, viruses, and bacteria, and transmitted by a living organism—often small, bloodsucking ones like mosquitoes, ticks, and sandflies—are known as vector-borne diseases. That carrier is called a vector. These diseases disproportionately affect the poorest populations in tropical and subtropical areas.

This scientist treated her own cancer

Virologist Beata Halassy treated her own breast cancer by injecting the tumor with lab-grown viruses. Though this self-treatment worked, it has not been approved for widespread use. Read to learn more about her fascinating experience, and how it has led to conversations about safety and ethics.

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

Three Ebola species are responsible for most large outbreaks of the disease, yet the only approved Ebola vaccine is known to work against just one of them.

What is the gut virome?

The gut microbiome's community of viruses is collectively known as the virome. It has been found to affect immune system development—important to the gut-brain axis—and has been implicated in the development of inflammatory bowel disease and Type 2 diabetes. As of early 2023, less than half of the viral sequences in the gut had been identified. Further study is needed to understand the virome's influence and therapeutic potential.

The 1957 and 1968 influenza pandemics caused millions of deaths worldwide

The 1957 H2N2 pandemic spread from East Asia, killing more than 1M globally, while the 1968 H3N2 pandemic began in Hong Kong and caused a similar toll, with both strains rapidly moving across continents.

Autoimmune diseases affect between 5% and 10% of people worldwide, but their causes remain unknown

Autoantibodies—which attack the body—may be detectable in the body years before a patient develops symptoms, but some people may have detectable levels yet never go on to develop an autoimmune disease. This video discusses this and other unsolved mysteries with autoimmune disease.

Less than 1% of people globally have schizophrenia, a syndrome strongly linked to genetics

Schizophrenia's causes remain largely unknown, though scientists suggest it's caused by multiple factors. Its symptoms include disruption of thought processes rather than the exhibiting of multiple personalities. This brief video provides an overview of the condition.

Paralysis from polio occurs in under 1% of infections

About 1 in 200 cases of infection causes paralysis. For paralysis to occur, the virus travels from the throat, intestines, and gut to infect specific cells within the spinal cord and brain stem that control movements. Within hours of invading the nervous system, paralysis can occur. The virus can be present in bodily secretions and stool for multiple weeks post-infection.

Ebola has an average fatality rate above 50%

The Ebola virus is one of the planet’s most feared bugs. Symptoms begin with fever and fatigue but quickly develop into severe vomiting, diarrhea, and internal and external bleeding. But why is it so deadly? In short, Ebola hijacks the immune system to rapidly make replicas of itself.

An estimated 1% of DNA mutations in bacteria can produce more dangerous strains

Researchers have developed a technique to monitor these mutations in real time. Using this technology, scientists found that mutations occur at a steady rate, with 1% leading to potentially deadly changes.

HIV originated in Central and West Africa from a virus in chimpanzees

Researchers believe the virus crossed from chimpanzees to humans through bushmeat practices in the early 20th century, with genetic studies suggesting the most recent common ancestor of the HIV-1 M group, which is responsible for the global AIDS pandemic, emerged around 1910–1930 in Léopoldville (now Kinshasa) in the Belgian Congo.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Lack of Vitamin D seems to be one major factor fueling MS risk

Researchers believe that a combination of factors can elevate MS risk, including a lack of vitamin D exposure in different locales, genetic history, cigarette smoke exposure, and Epstein-Barr virus infection.

Ringworm is caused by a fungus, not a worm

Ringworm, formally known as tinea and known for its red circular rash, is responsible for about 325 million infections at any given time—comprising roughly half the world’s fungal skin infection burden. It’s caused by a type of fungus called a dermatophyte, which also causes athlete’s foot and jock itch. Doctors typically prescribe antifungal tablets or powders to stamp out these fungal invaders.

Norovirus is the leading cause of food poisoning in the US

The illness is typically transmitted when virus-laden feces gets into another person’s mouth. That occurs when people do not properly wash their hands, contaminating food or surfaces.

The coronavirus pandemic sparked theories about the dangers of 5G

COVID-19 spreading around the same time as the rollout of 5G sparked conspiracy theories and outrage that the new wireless technology was harming people and the environment. (Some users may experience a paywall.)

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Experimental hantavirus vaccines and therapies, still under development, have long been funded by the US military.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

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.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

11 people died from firework injuries in the US in 2024.

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

Elk Cloner, the first computer virus to spread in public, was written as a practical joke by Richard Skrenta, a Pittsburgh high school student.

Poison ivy can cause rashes year-round since all parts of the plant contain urushiol, the oil that triggers our allergic response.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in terms of casualties, forces mobilized, and displacement of civilians.

Hotels in Cannes, the glamorous city on the French Riviera, hire hawks to ward off seagulls during the city's famous film festival.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.