The similarly named foot-and-mouth disease doesn't affect humans, unlike HFMD

Foot-and-mouth disease, which affects animals, has been eradicated in many locations

The disease, which causes fevers and painful blistering in the mouth, muzzle, snout, teats, and feet—somewhat similar to hand, foot, and mouth disease in people—is transmitted via contact with infected animals or their fluids or eating infected foods or meat. Though it primarily affects cloven-hoofed animals, it's also been known to sicken camels and even elephants.

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.

Hand, foot, and mouth disease spreads easily—including via fomites

The common ailment spreads through respiratory droplets, touching infected secretions like poop, but also by touching virus-laden fomites, which are contaminated objects such as doorknobs or toys.

Yes, many animals get malaria—not just humans

Birds, rodents, monkeys, lizards, bats, apes, and livestock are among the species that can become infected with malaria. Infected animals' symptoms often resemble those of humans, including fever, lethargy, loss of appetite and difficulty breathing. Birds will also have ruffled feathers and drooped heads.

'Tomato flu' outbreak in India turned out to be HFMD

An illness initially dubbed "tomato flu" in 2022 that sickened children in Kerala, India, with symptoms typical of hand, foot, and mouth disease turned out to be that—not a new ailment. A letter published in the prestigious journal The Lancet had initially described the illness as "a new virus" but at least some of the children ultimately tested positive for one of the viruses that causes HFMD, so it wasn't a new condition after all. (Some users may encounter a paywall.)

Adults usually have some immunity to HFM Disease—but can still spread it

In 2025, certain eastern states including Virginia and West Virginia reported a sizable uptick in their HFMD cases, particularly in their schools and daycare centers, though the reason for the larger outbreaks remains unknown. When adults or teens get the disease, their symptoms are usually mild or even asymptomatic. Still, they may pass the disease between people, too. (Some users may encounter a paywall.)

See the differences between chickenpox and hand, foot, and mouth

This helpful explainer breaks down the differences between these two contagious, viral diseases, which both present with fevers and sores. It includes photos of the sores that are characteristic of both diseases, showing how they have appeared across different skin tones to better inform people looking for information about their own loved one's symptoms.

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

Horses can—rarely—get West Nile, too

The animals can contract the virus via infected mosquito bites, but for horses there are four vaccines available. Though West Nile's often asymptomatic or mild in horses, the disease can sometimes be deadly, killing via severe neurological inflammation. There are no reported instances of people becoming sickened by infected horses or vice-versa.

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.

Marburg virus, related to Ebola, is also extremely deadly, and has no available vaccine.

Marburg virus, related to Ebola, is also extremely deadly

Discovered nine years before Ebola, Marburg is part of the same filovirus family. While this virus is less contagious, it can still be deadly. Currently, no vaccines exist against this disease. (Some users may encounter a paywall.)

Humans are the only known reservoir of poliovirus

The virus has not been found in any other species, which makes humans the only known reservoir for polio. In laboratory settings, nonhuman primates have also been infected with the virus, but there's no evidence that they contract the virus in nature.

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.

Bird Flu is spreading—what does that mean for us and other species?

The rapid global spread of H5N1 bird flu—from remote Antarctic islands to US farms—shows how animal spillover, driven by human activity and ecological disruption, is accelerating pandemic risk across species long before sustained human transmission begins.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Why don't giraffes get hypertension?

The average blood pressure of a giraffe is about double that of a human, yet they don't suffer from the symptoms of high blood pressure that humans do: stiffening of the left heart ventricle, shortness of breath, fatigue, or swollen legs and ankles. This article explains how giraffes have evolved to have the "biological equivalent of support stockings."

Inside the world's largest two-headed calf collection

The Two-Headed Calf MOOseum in San Francisco contains 50 taxidermied cow heads, all of which are paired with another one. They are the result of rare genetic mutations called polycephaly, that is, two-headedness. The museum is run by punk musician Henry Rosenthal, who first became captivated by the rare phenomenon in his 20s. Learn more about the exhibit here.

The Chinese market for donkey hides has created a new source of diseases

Since 1992, China’s donkey population has dropped more than 80 percent. This report examines how China’s booming demand for a traditional medicine known as e-jiao, made from collagen from donkey hides, is leading to the slaughter of 6 million African donkeys annually, and providing a new source for zoonotic diseases.

Humans are more genetically similar to cats than to dogs

While humans are not closely related to either cats or dogs from an evolutionary standpoint, scientists find that human and cat chromosomes are organized more similarly to each other than human and dog chromosomes, making cats a better model for studying human diseases.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw unprocessed state, and chewing mango skin can produce blister rashes

Poison ivy only seems to lead to allergic responses in humans, other primates, and guinea pigs. Other animals can both interact with the plant and eat it without becoming sickened.

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.

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

'Shoofly pie' was named after a molasses named after a mule named after a song

Although most people assumed the sweet dessert earned its name for its ability to attract flies, etymologists believe it can be traced back to a molasses brand named after a boxing mule (Shoofly the mule), who was named after a song ("Shoofly Don't Bother Me") that was a play on slang of the time.

What ancient goat teeth reveal about ancient human-animal relationships

About 4,000 years ago, several goats with terrible teeth managed to outlive their better-teethed brethren. With such intense dental damage, the goats were likely fed higher-quality feed than the more dentally gifted herd members, a dietary shift that would've contributed to the difference in life span. These goat teeth underscore the hard truth that humans may inflict harm on the animals they care about most, regardless of intention.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

Leprosy bacteria are sometimes grown on mouse feet for research

The main leprosy-causing bacterium can't be grown in a petri dish, so the disease is challenging to study in the lab. For research purposes, it has been grown in the foot pads of mice.

The okapi was once considered a cryptid, or an animal with an unverified existence

Similar to dragons or Bigfoot, the okapi was once believed to be a mythical animal, known colloquially as an "African unicorn." Its confusing features include zebra-like legs on a donkey-esque body with a giraffe-like head. However, this animal is both real and quite cute.

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.

After the patient died, a latent pig virus was discovered inside his xenotransplant

Researchers studying the death of David Bennett Sr., the first gene-edited pig heart transplant patient, discovered potential factors that may have contributed to his demise. One finding is that there was a latent virus, called porcine cytomegalovirus (PCMV), in the pig heart, which may have contributed to dysfunction of the transplant.

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

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

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

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.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

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.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

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

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

See images of medical cases of firework injuries shared on this 'Instagram for doctors.' (Warning: Graphic content)

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.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

Famed poet TS Eliot rejected the manuscript for George Orwell's political fable 'Animal Farm,' writing that its criticism of authoritarianism was not 'the right point of view.'

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

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

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

After her fellow cult members tried to kill her with an LSD-infused hamburger, one member of the Manson Family, the murderous cult led by Charles Manson, decided to testify against the group's leader.

'Saturday Night Fever,' the 1977 film that introduced disco to the mainstream, was based on a fabricated magazine story.

Mid-century modern graphic designers, known for their bright colors and bold lines in advertising, also found success with children's books.