The first major norovirus outbreak, in 1968, sickened half an elementary school.

Norovirus is the leading cause of food poisoning in the US

The illness is typically transmitted when virus-laden feces gets into another person’s mouth. That occurs when people do not properly wash their hands, contaminating food or surfaces.

HFMD was first reported in 1957 in New Zealand

The first clinical report involved eight kids with the characteristic sores in New Zealand, and then in the years that followed there were dozens more cases there and also reports of outbreaks in England and Scotland, among other settings, including the US.

A 1954 outbreak at a Boston boarding school allowed scientists to isolate the measles virus

While measles was described as early as the 9th century, humanity lacked the medical technology to fight the disease until the mid-20th century. Vaccine development from the Boston outbreak in the 1960s and 1970s led to one of the most effective inoculation campaigns in history.

At least 7 eastern college campuses experienced surprisingly large HFMD outbreaks in 2018

The outbreaks at the college level caused a particularly nasty set of symptoms, including the usual blisters in the mouth and on the hands and feet—but also affected the genitals. They surprised health officials who weren't sure why so many young adults were being sickened, including more than 120 kids at Johns Hopkins University. The disease also caused outbreaks at campuses including Princeton, Dartmouth, West Virginia University, Lehigh University, Wesleyan University in Connecticut, and Mars Hill University in North Carolina.

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.

There were 23 reported cruise ship outbreaks of gastrointestinal illness in 2025—something that happens often enough that there's a whole program at the US CDC devoted to tracking them.

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.

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 1957 and 1968 influenza pandemics caused millions of deaths worldwide

The 1957 H2N2 pandemic spread from East Asia, killing more than 1M globally, while the 1968 H3N2 pandemic began in Hong Kong and caused a similar toll, with both strains rapidly moving across continents.

'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.)

Severe cases of food poisoning have doubled even as food recalls dropped

Food recalls were down in 2024 by 5% as compared to 2023. But some researchers suspect that’s just because there were fewer inspections or fewer people reporting illnesses: Hospitalizations from food poisoning more than doubled during that same period, from 230 to 487, and deaths rose from 8 to 19.

In 2012, a virus that causes HFMD may have killed dozens of kids in Asia

More than 50 young children in Cambodia died in spring 2012 for unknown reasons, but laboratory testing of samples available from a limited number of those children came back positive for Enterovirus 71. That virus, which can cause HFMD, is known to cause severe complications among some people who contract the disease. But health officials concluded that poor baseline health and then incorrect treatment using steroids helped exacerbate their condition, helping lead to the deaths.

Maryland required cholera researchers to fly a yellow warning flag—signifying quarantine dangers in the 1970s

University of Maryland Hospital researchers intentionally infected volunteers with the cholera bacterium in the late 1970s to further their understanding of the disease. They proceeded with this work following the recommendation of a US government panel. (Some users may encounter a paywall.)

Lyme disease was first identified in Lyme, Connecticut in 1975

A cluster of 51 children and adults in the town all began experiencing uncommon arthritic symptoms and the cases were reported to the state health department. A quarter of the cases were preceded by a skin lesion. The patients tended to live near the woods.

Robert Koch won the Nobel for his tuberculosis work, but he also pioneered cholera research

Koch was one of the first scientists to isolate the bacterium that causes cholera while investigating an outbreak in Egypt in 1883. He went on to advise about rules to control cholera outbreaks, which formed the basis of the disease control approaches and water hygiene techniques still used today.

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.

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.

West Nile was reported in 47 states in 2025, with more than 1,400 people severely affected

Tracking numbers from the CDC indicate that the virus spread widely that year, with more than 2,000 reported human cases and many states seeing more than 25 sickened people. More than 1,400 people had neuroinvasive cases of the disease—meaning the virus had entered the nervous system, which can cause severe, potentially life-threatening illness.

A major US-designed polio vaccine was first tested in the Soviet Union

Albert Sabin's live attenuated virus vaccine—requiring two drops in the mouth—didn't garner political support in the US, so it was tested in the Soviet Union in the late 1950s.

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.

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

Since 1600, the longest stretch without an outbreak that killed 10,000 was four years

We think of pandemics as unlikely events, but disease outbreaks are surprisingly common. Over the past 400 years, the longest stretch without an outbreak that killed at least 10,000 people was just four years. The next pandemic can't be precisely known, so experts and policymakers focus on preparation.

Explore the cost of major viruses and other malware incidents through 2017

The first significant malware was the Morris worm in 1988, which caused an estimated $10,000 to $10M in damage to computers. With $38B in damage caused, Mydoom is the most costly piece of malware in history. Spread via email and, at one point, accounting for about 25% of all messages sent worldwide, the malware infected computers to create a botnet that launched cyberattacks.

In 1933, the influenza virus was first identified through “ferret flu” experiments

In 1933, British researchers dripped filtered nasal fluids from a sick colleague into ferrets, which quickly developed “ferret flu.” This experiment proved influenza was viral, not bacterial, and established the basis for modern flu vaccines.

In 2011, a mysterious illness spread around LeRoy, New York

A handful of girls were stricken with bizarre twitches, tics, and spasms — all apparently involuntary. Some believed the incident to be conversion disorder, an illness where emotional troubles have physical symptoms.

We're in the middle of a decadeslong cholera pandemic

In 1961, the world's seventh recorded cholera pandemic started in South Asia, and it has continued through the decades. India and Bangladesh are at particular risk. This pandemic is driven partly by conflict, population displacement, extreme weather, and poor water infrastructure.

See colorized mpox virus particles grown in culture at Fort Detrick, Maryland, where high-biosecurity pathogens are studied.

Listen to how the 1902 'poison squad' experiments changed food safety in America

As part of government research, a group of young men were paid to eat standard American food—replete with food additives like borax and formaldehyde—which revealed the dangers of unregulated food. The work was led by the first FDA commissioner, Harvey Wiley, who helped end the "century of the great stomachache."

Variola: the second-deadliest virus on Earth

Because it was declared eradicated in 1980, many forget smallpox is one of history's deadliest diseases—in its final century, it's estimated to have claimed 500 million lives. This 11-minute video from production studio Kurzgesagt takes a look at...

The Love Canal disaster exposed the dangers of buried toxic waste

In the late 1970s, residents of Niagara Falls, New York, discovered their neighborhood was built atop 20,000 tons of chemical waste. Leaking toxins caused illness and birth defects, sparking nationwide outrage and leading to the creation of the EPA's Superfund cleanup program in 1980.

See when the last case of wild poliovirus was found in each country

This chart shows when wild polio cases were last reported in each country worldwide. Beyond wild poliovirus, rare outbreaks can occur related to mutated strains of oral polio vaccine.

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.

Natural food stores began sprouting up in the US in the 1960s and 1970s

Health food stores began opening in the ‘50s, though they were primarily focused on vitamins and holistic supplements. Natural food stores, however, provided pesticide-free produce and often relied on local farmers for their products. One of the first was New Age Natural Foods, in San Francisco’s Haight-Ashbury neighborhood, which opened in 1965.

Penicillin ended scarlet fever’s deadly threat to children

Between 1840 and 1883, scarlet fever was among the leading causes of childhood death in the United States, with case fatality rates ranging from 15% to 30%. Today, thanks to antibiotics like penicillin, the mortality rate is below 1%.

Every virus is classified into 7 groups based on genetic differences

Viruses infecting humans have been named based on symptoms ("chickenpox") or the location or animal in which they were first discovered ("Bolivian Haemorrhagic Fever" and "Monkeypox"). For clarity among scientists and to reduce stigma, virologists classify the 15,000 known viruses (270 of which infect humans) by their basic genetic material.

Why we don't have an answer for the common cold

Since a landmark study of the common cold in 1925, researchers have learned much more about the seasonal ailment. Despite continuous study, people still contract colds for similar periods of time at the same rate with the same symptoms, and there's no vaccine. This article explains how the many viral strains make it hard to control.

In 1951, a small French town was overtaken by the fungus that ultimately led to LSD

During the summer of 1951, the French town of Pont-Saint-Esprit appeared to go mad. Hundreds were treated for hallucinations and delirium, with some reporting ongoing hallucinations a month after the LSD-like symptoms appeared. Some historians argue it was a case of ergotism, better known in the Middle Ages as "burning disease" and "St. Anthony's Fire."

The canal carried germs as well as goods

In 1832, North America’s first cholera epidemic spread inland by way of the Erie Canal, carried by immigrants arriving on ships. Fearful towns barred passengers from disembarking, yet cholera, smallpox, and other diseases still traveled the waterway.

Childhood memes like '67' existed before the internet

Kids saying "67" and then erupting in laughter may have been popularized by social media, but childhood rhymes, songs, and jokes that confuse adults have always existed. Iona and Peter Opie studied the phenomena, publishing numerous books on the topic from the 1950s through the 1980s.

The Kent State massacre sparked a nationwide student strike

In 1970, the Ohio National Guard opened fire on Kent State University students—peacefully protesting the Vietnam War—and killed four. The tragedy led to more widespread nationwide protests, shutting down more than 200 colleges and universities. The event led to a Pulitzer Prize-winning photo of a slain and grieving student.

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.

Two-thirds of antibiotic classes were made between the 1940s and 1960s

The vast majority of bacterial treatments were developed during the "Golden Age of Antibiotics," an era of rapid innovation and drug discovery that led to the reduction of millions of deaths worldwide. Since 1970, only eight new antibiotic classes have been discovered.

Revelations that apples were sprayed with the chemical Alar led to its ban in the 1980s

Almost three decades after Rachel Carson’s “Silent Spring,” a “60 Minutes” segment on the use of Alar, a chemical sprayed on apples, drew national attention and inspired supermarkets and schools to remove apples from their shelves and cafeterias. That same year, the Environmental Protection Agency took action against the use of the chemical in food.

Peter Norton, for whom Norton Antivirus is named, questioned the threat of viruses

The software author was among several computer experts in 1988 who suggested that reports on the threat of computer viruses were exaggerated, referring to testimonials of infections and their spread as "urban legends."

See a census of college students dating back to 1850

The first mention of college students in census surveys dates back to 1850, when officials realized a sizeable proportion of Americans lived on campus. More modern data from the National Center for Education Statistics capture the growth in the student population, with a breakdown beginning at the end of World War II with gender and type-of-institution data.

Oral rehydration solution was developed in the 1960s in response to cholera deaths

Drinking this life-saving mix, which consists of clean water, salts, and sugar, helps the human body rehydrate after extreme bouts of diarrhea, vomiting, or both. It's now used for a variety of diarrheal diseases.

A television show helped popularize sushi in the US in the 1980s

"Shogun," a miniseries released in 1980, followed a British sailor's journey through 17th-century Japan. Nearly a third of American households watched its five installments, and it was used as an instructional text in classrooms throughout the '80s, inspiring a wave of American interest in Japanese culture, including sushi.

Food allergies were first documented more than 4,000 years ago

Although food allergies are on the rise in modern times, they have been documented in written records for thousands of years. More than 3,000 years ago, Chinese emperors advised patients to avoid certain foods, and Hippocrates noted in his work that food could cause serious harm to certain individuals, and even lead to death.

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.

The origins of public education in the US stem from Puritan religious views

The 1647 Old Deluder Satan law reflects Puritan belief that illiteracy allowed Satan’s influence. The law—the first of its kind in the colonies—mandated towns of over 50 households hire a teacher and over 100 support a grammar school.