Poliomyelitis is derived from Greek

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.

View this timeline of polio milestones and vaccine development

Polio has a long history in art and medicine, dating back centuries. It includes a representation of an apparent polio survivor with a shriveled leg in ancient Egyptian art. See milestones in the history of polio in this timeline.

Polio commonly spreads when virus-laden feces gets into our mouths

This highly infectious disease is transmitted from one person to another, mainly when we eat virus-laden poop particles. Less frequently, contaminated food or water can transmit the virus, or people can be infected via respiratory droplets (from coughing or sneezing).

Most polio cases today are vaccine-derived rather than naturally occuring

Weakened, live virus vaccines—which aren't offered in the US—carry a risk of virus being shed in the stool. Rarely, the shed virus mutates and leads to vaccine-derived polio infections. Most recent polio cases are genetically linked to those vaccines. As shown in this graphic, there are typically hundreds of vaccine-derived polio cases annually.

Improved 19th-century sanitation meant kids encountered polio later, with worse results

Almost all children likely used to contract poliovirus, but scientists suggest that when infants encountered it very early in life—due to poorer conditions and hygiene—they still had some maternal protection from pregnancy or through breastmilk, so the symptoms were more flu-like.

Hand, Foot, and Mouth Disease is part of the same virus family as polio

These viral infections are both caused by enteroviruses, which are a group of single-stranded, non-enveloped RNA viruses. Several different enteroviruses are known to cause this condition, including Coxsackie virus A16, Enterovirus 71, and Coxsackie virus A6.

Ebola is a filovirus, meaning it resembles a thread under a microscope

Filovirus is derived from the Latin word 'filum', meaning 'thread.' That term describes its thin, flexible, threadlike appearance. Originally isolated in 1976, the microscopic image of the Ebola virus is now famous, even portrayed in the movie Outbreak. In fact, Ebola's threadlike appearance can vary in both length and degree of twisting, sometimes resembling a bowl of spaghetti.

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

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."

Malaria comes from the Italian term 'mal'aria,' meaning 'bad air'

The term refers to marshy areas associated with the disease. An estimated 94% of malaria cases—215 million—occur in Africa.

After FDR was paralyzed by polio in 1921, Eleanor Roosevelt became active in politics and supported his political ambitions

FDR contracted polio at age 39 and permanently lost the use of his legs. Eleanor Roosevelt persuaded him to stay in politics, then took on the task of maintaining his public profile—attending events, building relationships, and serving as his "eyes, ears, and legs" across the country.

The word 'vertigo' derives from the Latin 'vertere,' meaning to turn

Beyond the word's origin, this article makes clear that fuzzy definitions of the disorder make it confusing for patients to describe it.

The virus was officially described for the first time in 1789

Michael Underwood, an English physician and surgeon, was the first to describe the disorder, noting it caused disability in the lower extremities in children. Large-scale outbreaks of the disease were not observed until the late 19th century.

'Melancholia' was the ancient Greek term for depression

"Melancholia" in Hippocrates's time was derived from the Greek word for black bile. This term made sense in its context since the Greeks believed that depression stemmed from an improper balance of the four humors.

The word 'Peloton' comes from the word for the main group of riders in a cycling race

The word itself is French for "ball," but became the inspiration for the word "platoon" in the 17th century to describe a group of soldiers. Now, it's a common cycling term and the main focal point in cycling races.

Physiological muscle memory allows us to quickly regain lost musculature

The term "muscle memory" is most often associated with the neurological kind, which involves the development of strong and efficient neural pathways in the brain and spine. Physiological muscle memory also slows the loss of muscle mass, with both types affected by genetics and diet.

Measles evolved from an ancient cattle disease as early as 3,000 years ago

Genetic analysis suggests that the closest modern relative of measles is a livestock virus known as rinderpest, with the viral strains diverging between 2,000 and 3,000 years ago. The timing coincided with the rise of major cities above 250,000 people, offering a novel transmission route for the newly mutated measles virus.

How ALS (Lou Gehrig’s Disease) might work, and what scientists are learning about it

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that affects the nerve cells (neurons) controlling muscle movement. As the motor neurons degenerate, they stop sending signals to the muscles, causing progressive muscle weakness and, eventually, death. This three-minute animation focuses on the mechanisms within the motor neurons that cause them to degenerate. By understanding these mechanisms, researchers hope to one day find a cure for ALS.

The word peptide comes from Greek

Originating from the Greek term "peptos," which means digestible, peptide as a word refers to two or more amino acids. (Some users may encounter a paywall.)

Sclerosis is the technical term for the lesions or plaques that form without myelin

In the absence of myelin, the body forms scar tissue called sclerosis. That scar tissue hampers nerve's abilities to transmit nerve impulses, essentially acting as a roadblock to speedy communication.

The ancient Greeks laid the foundation of Western culture, from ideas to sports

The Latin alphabet is the most used in the world and stems from the Greek language. The greatest sporting event in the world, the Olympics, originated among the Greeks. The way many countries decide on policy is via forms of democracy, an innovation of the ancient Greeks.

Rodent evidence is mounting that dysfunctional mitochondria may be a cause of Parkinson's

Though researchers have long observed mitochondrial malfunction in Parkinson's patients, it has remained unclear whether faulty mitochondria cause the disease or are casualties of it. Rodent research published in 2025 adds further weight to the idea that it's causative.

The wonderfully named Vibrio diabolicus is a cousin of the cholera-causing bacterium

This bacterium, which belongs to the same genus as the cholera bacterium, was initially isolated from deep-sea hydrothermal fields. It was sampled from water that was scooped up during a French-American cruise in October 1991.

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.

Why we should care about renaming the hormonal disorder PCOS to PMOS

The new name, polyendocrine metabolic ovarian syndrome, nods to the hormonal disruptions that cause this condition, which affects roughly one in eight women. People with PMOS may have symptoms including irregular periods, trouble conceiving, weight gain, acne, undesired hair growth, and more. The earlier name, polycystic ovary syndrome, was a misnomer because women with the condition don't have cysts in their ovaries. Rather, they have masses that are actually immature follicles. World health experts think the condition often goes undiagnosed.

The political ideology of fascism originates in Italy

Fascism—first named by Benito Mussolini in 1919—derives from the Italian word fasci, linked to the Roman fasces, symbolizing authoritarian unity. Mussolini adapted this term to represent his autocratic, ultranationalist movement.

The origins of volleyball in a game called mintonette

Volleyball was invented in 1895 in Massachusetts, USA, by William G. Morgan of the YMCA. He aimed to create a less strenuous alternative to basketball, using elements from basketball, tennis, handball, and baseball. Originally called "mintonette," it was introduced at a YMCA conference and took off. Dive into the history from then until today here.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

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

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

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

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

Lesser-known phobias include turophobia, or the fear of cheese, and nomophobia, the fear of being without your cell phone.

Graffiti dates back to at least ancient Pompeii, where citizens scrawled messages to one another on public walls

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

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.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

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.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

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.

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.

El Niño, Spanish for 'the boy,' was named after Jesus Christ because the phenomenon resembled the weather changes observed around Christmastime.

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto