Norovirus is the leading cause of food poisoning in the US

1 in 6 Americans get food poisoning each year

The US federal government estimates there are about 48 million cases of foodborne illness in the country annually, resulting in as many as 3,000 deaths and 128,000 hospitalizations. Food poisoning puts those with weakened immune systems, the elderly, pregnant people, and young children at particularly high risk. This chart of common disease-causing pathogens highlights common threats and details about them, including likely food sources.

The first major norovirus outbreak sickened half an elementary school

In 1968, 50% of an Ohio school got ill from this foodborne pathogen. The disease name is a nod to that original strain discovered in Norwalk, Ohio, when half the elementary school students became ill. Almost all kids reported nausea and vomiting. Everyone recovered.

Restaurants are where most of us contract food poisoning in the US

From 2014 to 2022, most reported foodborne illness cases occurred at restaurants. Between 2020 and 2022—when COVID-19 also likely influenced restaurant eating habits and tracking—there were only 238 foodborne illness outbreaks linked to restaurants, down from 714 the prior two years. Still, restaurants were behind most reported outbreak cases. (Some readers may experience a paywall.)

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).

See why food poisoning makes you feel nauseous

Scroll through these illustrations to learn what’s happening behind the scenes with bacterial foodborne illnesses, including why we sometimes vomit and how the body reacts to toxins secreted by bacteria.

Swimmer's ear is America's most common waterborne illness

Federal government analysis of the roughly 7 million waterborne illness cases that occur annually in the US found that swimmer's ear comprises some 4.7 million, or 65%, of the annual waterborne illnesses and 20% of hospitalizations. Norovirus infection comes in second place.

Food companies usually issue recalls voluntarily and you can be automatically notified about them

Protecting yourself from food poisoning means staying on top of food recall announcements. Notices about these from the US government, which you can automatically receive after signing up at this link, note what products have been recalled by food companies. Companies alert the US Food and Drug Administration or the US Department of Agriculture when they issue recalls so the public can stay informed.

Hand, foot, and mouth is usually seasonal—peaking in summer—but not always

This painful, contagious disease most commonly has outbreaks in summer and early fall in the US because the enteroviruses that cause disease can most readily survive and be transmitted in warmer, humid conditions. It can still show up throughout the year, however.

We can get food poisoning from spending time in swimming pools, lakes, rivers, and ponds

Some of the same pathogens that may sicken us in food or water may also sicken us in recreational swimming environments. Bacteria can rub off of people’s (or animal’s) bodies or contaminate the water through a diarrheal episode. Washing your hands for at least 20 seconds before eating food if you are at the beach, pool, or other similar environments and being sure not to swallow the water are ways to help keep safe.

Foods shouldn't be defrosted on the counter, but microwaving to defrost is okay

This wide-ranging video from the US Food and Drug Administration explains causes of food poisoning and tips for consumers. The agency's advice includes that we should separate meat and eggs from our veggies and fruits in our shopping carts, during food prep, and in the fridge (with meat located below veggies in the refrigerator in case it drips).

1 in 4 people around the world don't have access to clean water

Poor water sanitation puts people at risk of acquiring this diarrheal infection. Cholera infections are on the rise due to extreme weather events and conflict. In recent years there have been cholera outbreaks in locations that hadn't seen the disease in many years, including Haiti.

Eating street food while traveling isn’t recommended, but there are ways to do it more safely

The US Centers for Disease Control and Prevention urge people to stay away from street food while traveling. But if you still want to eat it, the agency recommends making sure it’s cooked food and that it’s served steaming hot. Also, avoid eating any raw vegetables as they may be more likely to harbor pathogens.

In the 19th century, ice-cream-related illnesses were somewhat regular in America

Ice cream was a popular dessert, but it was also a dangerous one, with numerous reports of vomiting, diarrhea, and—in some cases—death. Historians argue this was likely due to vendors' poor hygienic practices.

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.

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.

Heat is the leading cause of death in natural disasters

Floods are a distant second, followed by hurricanes. That's according to data reported by the National Oceanic and Atmospheric Administration.

In 1892, two scientists purposefully infected themselves with cholera bacteria

When they became ill—one with mild diarrhea and the other with severe cholera—researchers pointed to that as proof that the pathogen caused the disease.

Watch an expert's take on the rare disease hantavirus—and why it's not of great concern to the general population

This rare zoonotic disease, transmitted to humans primarily through infected rodent droppings, urine, or saliva, is rarely spread between people. The disease was of particular concern in spring 2026, when an outbreak occurred on a 150-person cruise ship, prompting a flurry of action, including contact tracing for passengers in their home countries. The disease can be fatal. But early care—primarily oxygen support—can help patients survive.

How a worm helped give the southern US its reputation

"The germ of laziness" that blanketed the southern US for centuries with unshakable fatigue, brain fog, and distended bellies paired with emaciated frames was actually a worm. This parasitic worm lives in the gut, where it can stay up to five years, laying up to 10,000 eggs daily. Hundreds of millions of people worldwide continue to suffer from hookworm infections, often obtained by walking barefoot across infected soil.

Mosquito-borne illnesses have killed captive orcas at SeaWorld

After two SeaWorld orcas died from viruses carried by mosquitoes, scientists warn that mosquito-borne illnesses may be a bigger threat to these captive animals than previously known. Captive orcas spend a lot of time stationary, close to the surface, unlike their wild counterparts. Researchers saw mosquitoes landing on the animals' backs, heads, and dorsal fins, supping on their blood.

The 'kissing bug disease' occurs when a bug's parasite-laden poop gets into your blood

Chagas disease transmission can occur when triatomine bugs bite someone infected with a Trypanosoma cruzi parasite and then bite someone else, passing on the pathogen, though the parasite can also be transmitted in other ways, including via food, congenitally, and through blood transfusions. The bugs tend to feed at night and can bite anywhere on the body, but their reputation for biting people around the mouth and eyes created the idea that the bugs were "kissing" humans. Recent research suggests the disease may be endemic in the US.

Roughly 1 in 5 cancers are caused by viruses

About 20% of cancers are caused by viruses, with seven specific oncoviruses causing between 10% and 15% of cancers worldwide. These include human papillomavirus and hepatitis B and C viruses, which can lead to diseases such as cervical and liver cancer. Understanding the mechanisms of these viruses is crucial for prevention and treatment strategies.

Drug-resistant staph infection is one of the deadliest superbugs

Methicillin-resistant Staphylococcus aureus (MRSA)—the superbug version of staph infection—is responsible for more deaths than any other superbug, killing more than 120,000 people globally each year. The bug is leading cause of hospital infections, and is harmless on the skin but causes severe symptoms once inside the body.

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.

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.

Roughly 15 of every 1,000 people in the US have smell disorders

Anosmia is a lack of a sense of smell. It can be present at birth, related to diseases including Parkinson's, Alzheimer's, and COVID-19, or have unknown causes.

Cutting mold off your food does not make it safe to eat

Mold is a type of fungus, but not all fungi are molds. This video explains the value of mold, mold anatomy, health concerns around encountering and eating mold, and why mold is found all around us.

Between 10 million and 50 million people in the US develop rashes from poison ivy, poison sumac, and poison oak each year.

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.

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

'Shogun,' a 1980s TV series, helped popularize sushi in the US by stimulating an American interest in Japanese culture.

View the ten deadliest tornadoes in US history.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

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.

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

Some researchers have labeled nomophobia, the fear of being without your phone, as 'the phobia of the 21st century.'

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

The US first hosted the World Cup in 1994, a tournament that lives in soccer infamy for its poor planning and the murder of Colombian player Andres Escobar, who'd accidentally scored on his own net.

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

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

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

Fireworks-related ER visits are on the rise—in 2024, they increased by 52% as compared to the prior year.

The US dollar is the most widely circulated currency in the world, and is involved in nearly 90% of global transactions

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

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.

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.

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

Explore fun facts from the USPS, including unique post office buildings, a stamp that traveled past Pluto, and more.

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.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission