Recent research indicates leprosy was present in the Americas before European settlers

Up to 225 cases of leprosy in the US are diagnosed each year

Most cases in the US are imported, meaning someone was infected in a country where it was more common. Since symptoms can sometimes take decades to appear, tracing the origin of the disease can be hard.

Lyme disease-causing bacteria predate any suspected biological weapons testing

Borrelia bacteria existed long before any US biological weapons program—or human presence in North America. One study comparing genomes of the bacteria behind Lyme disease collected samples of the bacteria over three decades and calculated that the bacterium has been in North America longer than humans, at least 60,000 years. Other work found related bacteria preserved in amber from millions of years ago.

Europeans' arrival to America brought disease to Indigenous populations

Indigenous people lived in the Americas for centuries before the arrival of the first Europeans in the 15th century. Their arrival was disastrous for Native tribes; in addition to being enslaved and losing their land, they had no natural immunity to the diseases brought by colonists. Eventually, up to 95% of the Native American population was killed by illnesses including typhus, chickenpox, and cholera, an event now known as the Great Dying.

81% of Florida's leprosy cases occur in central Florida, raising concerns

Researchers noted in 2023 that about one-fifth of new US leprosy cases were reported in the central part of the Sunshine State. What's more, about a third of the new US cases overall appear to have been acquired locally, raising questions about whether the disease is now naturally occurring in parts of the southeastern US.

People can—and have—contracted leprosy from armadillos

A 2011 study linked multiple human cases to the handling of armadillos or the consumption of their meat. The research couldn't document direct transmission, but did find that the animals and humans shared the same exact strain of the disease.

America had a national leprosarium—a leper colony—in Louisiana until 1999

Public health officials forcibly sent those diagnosed with leprosy to the Louisiana Leper Home in Carville, first founded in 1894. Listen to an interview about this site, its evolution, and how its residents advocated for themselves—including regaining the right to vote.

Measles reached global transmission during the 15th- and 16th-century Columbian exchange

Devastating diseases like smallpox, influenza, measles, and other viruses were largely introduced into the Western Hemisphere beginning with the 1492 arrival of Christopher Columbus and the ensuing age of exploration.

See examples of leprosy in the Bible—a broad term for skin ailments in ancient times

People afflicted with leprosy in the Bible may have had a range of different skin diseases, rather than what's clinically diagnosed as Hansen's disease (leprosy) today. In the Bible, as in many traditional societies, those with the disease were often considered unclean or sinful.

The first Americans arrived between 14,000 and 40,000 years ago

Early peoples migrated to the Americas via the Bering Land Bridge or coastal routes, spreading across the continent as hunter-gatherers. Archaeological sites in present-day New Mexico containing stone tools and animal bones mark some of the earliest confirmed evidence of human life in North America.

Listen to what it was like living as a medieval leper

This podcast uses paleopathological and anthropological findings to reconstruct what it was like for people diagnosed with leprosy in medieval times on the Eurasian continent. If a town lacked a leprosarium—an isolated leper asylum or colony—or the suspected leper was a foreigner or a Jew, which would make them ineligible for leprosarium admission, they'd be expelled.

Wild chimpanzees have been spotted with leprosy lesions

In research published in 2021, scientists reported discovering cases of leprosy in wild chimpanzees from Guinea-Bissau and the Ivory Coast—marking the first time the disease has been found in any nonhuman species in Africa. They confirmed that leprosy was the cause of the deformities by testing the animals' poop for the presence of the disease-causing bacteria.

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 American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

The American cockroach is actually from Africa—an apparent hitchhiker aboard ships carrying enslaved people—with evidence suggesting it may have arrived in the New World as early as the 1600s

This podcast delves into the history of Periplaneta americana and explores why the bugs elicit such fear, disgust, and, at times, shame. The bug likely climbed aboard the slave ships because they had both unprotected food sources and places to hide during their journey.

The cholera bacteria was first isolated in 1854—but the discovery was largely ignored

The pathogen was isolated by the Italian physician Filippo Pacini in Florence, Italy, though his discovery was largely ignored in favor of the popular miasma—bad air—theory of disease at the time. The pathogen was separately isolated about three decades later by German microbiologist Robert Koch.

Even in recent history, adaptations to the environment drove human evolution

Through genetics, environmental pressures, and cultural influences, humans have evolved to tolerate lactose, develop varying skin pigmentation, and acquire genetic resistance to diseases like bubonic plague. The metabolic and digestive systems of Indigenous peoples have adapted to their diet, which is influenced by the availability of food and water.

Evidence of cancer has been found in a 1.7-million-year-old fossil

Cancer has existed as long as humans have, with some of the earliest evidence found among fossilized bone tumors, human mummies in ancient Egypt, and ancient manuscripts. The oldest example was uncovered in a toe—millions of years old—from an ancestor of modern-day humans.

The concept of life insurance likely originated in ancient Rome around the year 100 BCE

However, life insurance policies didn’t reach the Americas until 1759, when life insurance started being used to protect the families of Protestant ministers when said ministers died. This timeline of life insurance’s early history—and how it has evolved since then—provides more details.

European colonists encountered barbecue by the 16th century

They called the food “barbacoa” and spread the technique throughout their territories, including the American colonies. The first recorded mention in English appeared in John Lederer’s travelogue of Virginia and the Carolinas in 1672.

How scientists know invasive nutria were likely introduced to California by humans

Although native to South America, DNA testing of the semiaquatic rodents showed they are closely related to a population in Oregon, suggesting they were deliberately transported into the state. First identified in the San Joaquin Valley in 2017, the distance, terrain, and lack of nutria between the two regions has allowed researchers to rule out natural migration.

Humans have speculated about alien life since ancient times

Around 50 B.C.E., Roman poet and philosopher Lucretius shared the idea that alien life was possible, which was put forth by Greek philosopher Epicurus. The writing is believed to be the first straightforward assertion in Western literature that aliens must exist.

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

Human settlements may be older than previously thought

This narrative article follows an archaeological team as they sift through the remains of Nahal Ein Gev II, an ancient village near the Sea of Galilee in Israel. Abandoned about 12,000 years ago, the site has been investigated for years and...

The expedition documented 240 plant species, 178 new to western science

Lewis and Clark’s botanical records introduced species to Americans like bitterroot, ponderosa pine, and Oregon grape—plants unknown to western science at the time. See a selection of these species in this image gallery.

Western babies often are missing a key gut microbe common elsewhere

Studies show infants in Europe and North America often lack Bifidobacterium infantis, a microbe widespread in babies in Africa and South Asia that helps digest breast milk and train the immune system. Researchers link the gap to antibiotics, formula use, and sanitized spaces.

Psychoactive drugs found in 1,000-year-old bag made of fox noses

Archaeologists in Bolivia have uncovered an ancient bag filled with "amazing goodies" that suggests the owner or owners were well-versed in the properties of psychoactive substances and sourced goods from well-established trade routes. This article details the findings, which shed light on how ancient peoples in the region consumed and obtained psychoactive substances.

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

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity, where it was purposefully grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

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

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.

This real-time tracking of the hantavirus cruise ship outbreak in May 2026 offers a unique glimpse into the global reach of the outbreak and whether the virus sickened passengers and their communities around the world.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

The 2026 Ebola outbreak is hampered by a lack of vaccine against the species of the virus, heightening the need for rapid tests to aid in disease control.

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

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

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

In 2019, a laptop loaded with six of the worst malware in history and described as 'an exhibit of historical weaponry' sold for $1.3M.

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

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

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

See a 3D reconstruction of Tenochtitlan, the Aztec capital that was home to an estimated population of 200,000 to 400,000.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

Despite being favored by 87% of Americans, Congress does not have term limits.

A researcher recently discovered an interview from 1967 between groundbreaking journalist Joan Didion and the Grateful Dead, years before the band became an institution.

'Grand Canyon of the Yellowstone,' a work by American painter Thomas Moran, inspired Congress to establish Yellowstone National Park.