Leprosy doesn't cause fingers or toes to fall off

Nerve axons become damaged by leprosy, so patients may lose feeling in their skin

Infection of the peripheral nerves—nerves outside the brain and spinal cord—is a known complication of leprosy. That damage can cause patients to lose their sense of touch and the ability to feel pain or temperature in affected areas, leading to accidental injury.

Leprosy affects the skin, eyes, and upper respiratory tract

Untreated, the disease can lead to permanent nerve damage and the loss of sensation in arms, legs, and other extremities. The exact form of transmission remains unclear, but scientists suspect it is spread via respiratory droplets over a prolonged period. (Warning: Graphic content, including photos of deformities.)

Watch how doctors examine leprosy patients for signs of vision impairment

Clinicians must screen for symptoms of eye and vision damage in leprosy patients, including loss of sensation, reduced blink reflex, and inability to close or keep the eyes closed.

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.

Research suggests the brain maintains connections to lost limbs

Decades-old research suggested brain reorganization after amputations, but brain scans show unchanged limb representations. Phantom limb pain may result from such unchanged brain maps, which may enhance prosthetic limb control in brain-computer interface technology.

Firework or sparkler burns can have large effects on our hands' range of motion

Dr. Erin Miller, a hand surgeon at Harborview Medical Center in Seattle, describes the range of injuries she's seen from firework injuries in this 2020 video. The damage includes loss of hands, fingers, and tips of fingers. Miller describes how in a recent year she was on-call during the week of the Fourth, and in just five days she saw 30 cases and had to amputate 42 fingers because of fireworks injuries.

Humans won't develop more than 5 fingers because it would impact too many body parts

All modern animals have five or fewer digits on each of their limbs. Roughly 348 million years ago, at least two species had eight: the Ichthyostega and the Acanthostega. According to Dollo's law, complex evolved features are very unlikely to recur in evolution. Researchers believe humans won't develop more than five digits because it would impact other body parts too much.

Firework or sparkler burns, even if they cover a relatively small area of skin, can significantly affect our range of motion.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

Sepsis is the leading cause of death in hospitals

Sepsis is the result of an overly aggressive immune system trying to combat infection, triggering inflammation throughout the body. After it begins, each passing hour increases the risk of death by 4% to 9%, and an estimated 350,000 people die from the condition in the US each year.

Measles infection can cause long-term immune system “amnesia”

The measles virus attacks the body's immune system, including preying on T and B cells in the lymphatic system. These cells hold memories of past infections, which can be degraded as the virus destroys them. This leaves patients susceptible to other infections for a year or longer.

Post-polio syndrome occurs decades after infection but isn't contagious

Affecting adults who contracted polio as children, this disorder can occur 15 to 40 years later, leading to slow, irreversible muscle weakening. Some research estimates that between 25% and 40% of polio survivors go on to develop this condition.

Food poisoning can sometimes cause serious long-term health issues

Although foodborne illness can be relatively mild and cause short-term discomfort, more rarely it can also cause long-term severe health consequences, depending on your individual risk factors, the severity of your sickness, and the care you receive. Kidney failure is one serious complication associated with certain types of food poisoning. Meningitis, hepatitis, arthritis, and pancreatitis are also rare and serious foodborne illness complications. If a pregnant person gets food poisoning, it can cause health issues for the fetus.

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.

Black Americans with diabetes have amputation rates three times higher than average

Annually, 130,000 US diabetics undergo amputations due to complications from diabetes, with many patients located in low-income and uninsured neighborhoods. More than half of US diabetics who lose lower limbs are not subject to pre-surgery angiograms, imaging that shows blood flow blockages to determine if (and where) amputation is necessary.

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.

Your feet can expand—permanently—due to pregnancy

A hormone called relaxin loosens tissues in the body to allow them to expand during pregnancy, affecting muscles and body parts—including the feet. The structural changes that occur in the foot as it expands are sometimes permanent. This article states that researchers have found as many as 61% of new moms did not have their foot sizes return to their prepregnant state. (Some users may encounter a paywall.)

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

Being struck by lightning has a mortality rate of about 10%

Near-immediate deaths are the result of electrical disruptions in the heart and nervous system, causing cardiac arrest, but severe skin burns, temporary paralysis, and blown eardrums are more common. About 74% of survivors are left with a long-term disability, which includes brain damage and changes in memory and mood.

Hearing loss can affect balance and make falls more likely

For reasons that are not yet fully understood, hearing loss seems to increase the risk of falls. One explanation is that reduced environmental awareness due to hearing loss may put people at greater risk. Another theory is that the brain has to work harder to process sound with hearing loss and that cognitive load may also boost the chances of falls. One study found that for every 10 decibel increase in hearing loss, there was a 1.4 fold increased odds of falling in the preceding 12 months.

See how the Ebola virus affects blood circulation in the human body

Ebola infects and disables immune cells, causing a cascade of events that result in small blood clots throughout the body, weakening blood vessels, and interrupting blood flow to key organs.

Loss of sense of smell is a common symptom of COVID-19 infection

In 2020, researchers discovered why this occurs. The virus that causes this infection attacks the cells that support smell-detecting neurons. Once infection clears, the sense of smell typically returns, though the exact timeline for that differs by patient. (Some users may experience a paywall.)

Theoretically, you could lose a bunch of your organs and still survive

If surgeons removed organs including one of your lungs, a kidney, your spleen, appendix, tonsils, part of your liver, and even some of your reproductive organs you could still survive. Watch this animated video which dives into the organs you could conceivably live without.

She can't feel pain, hunger, or danger

Olivia Farnsworth, born with a rare chromosome 6p deletion, may be the only person known to lack pain, hunger, and fear responses. This overview explores her unique condition, the incredible incidents that revealed it, and how scientists hope her case could unlock new insights into human survival and sensory systems.

Breaking down various tongue disorders, from infections to genetics

Taste is one of our fundamental senses, but can be impeded by a wide variety of conditions including glossitis, angioedema, and black hairy tongue. Most are characterized by their color, shape, and sometimes change in function. Causes range from vitamin or mineral deficiencies to fluid accumulation, fungal infection, or more.

Blood tests for Lyme disease tend to come up as false negatives in the week after a bite

It can take several weeks for Lyme antibodies to develop, which is what blood tests would be detecting. That's why many clinicians will prescribe antibiotic treatment immediately after a bite if the individual develops the characteristic bullseye rash of Lyme or gets bitten in an area of the country known to have high rates of Lyme.

Symptoms of DNA loss may mimic those seen in mushroom poisoning or chemotherapy

Although no organism has ever lost all its DNA, the destroying angel mushroom contains amatoxin, which disrupts DNA transcription and is known to cause death via liver and kidney failure in three days. Doxorubicin, which tangles DNA to disrupt cellular replication, compromises a person's immune system.

Explore why swimmer's ear will not go away on its own

This infection is typically treated with ear drops to reduce inflammation and fight the bacteria or fungus that led to the issue. But without treatment, complications can arise, including a deep tissue infection, bone or cartilage damage, or—very rarely—spreading beyond the ear into the skull bones and surrounding areas.

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

Watch what the Ebola virus does inside our cells and organs in order to spread and survive.

Tattoos remain visible on your skin thanks to immune cells called macrophages

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

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

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

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.

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

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

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

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

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.

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.

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.

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

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

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'