Human records of influenza stretch back more than two millennia

Human records of influenza stretch back more than two millennia

Accounts of flu-like illness appear as early as 412 BCE, when Hippocrates described a sudden wave of cough and fever. Centuries of recurring outbreaks culminated in the first clearly documented pandemic in 1580, spreading from Asia into Europe and Africa.

Europe’s first recorded influenza pandemic swept the continent in 1580

The 1580 influenza pandemic, traced from Asia to Africa and into Europe, became the first flu outbreak clearly documented across the continent—killing tens of thousands and highlighting influenza’s potential for rapid global spread.

A timeline of major pandemics from 1899–2025

Modern pandemics have been defined by the race between globalization (which increases risk) and the development of new medicines. The Great Influenza epidemic claimed some 50 million lives, and the COVID-19 pandemic killed more than 7 million. In between, diseases like Ebola, cholera, AIDS, and more have devastated communities.

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.

How the 1918 pandemic spurred developments in virology and vaccines

This article provides an in-depth historical account of the 1918 Spanish Flu pandemic, including its impact on the global population and how its occurrence spurred significant advancements in the study of viruses—laying the groundwork for the...

In 1933, the influenza virus was first identified through 'ferret flu' experiments, which proved that the disease was viral—not bacterial.

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

Hear firsthand stories from Americans who lived through the 1918 flu pandemic

This video shares personal accounts from survivors of the 1918 influenza epidemic, capturing memories of sickness, loss, and resilience. Their voices offer a glimpse into how ordinary people experienced one of history’s deadliest pandemics.

A novel H1N1 influenza strain sparked a 2009 global pandemic

First detected in Mexico, the 2009 “swine flu” pandemic infected up to 1.4B people worldwide. While mortality rates were lower than earlier pandemics, the outbreak still caused more than 150,000 deaths.

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.

The word 'influenza' comes from a 15th-century Italian belief in the stars

In Renaissance Italy, epidemics were thought to result from the influence of natural disasters or celestial bodies. The illness was named "influenza", meaning “influence” in Italian.

Why the 1918 flu killed between 50 and 100 million people

The 1918–1920 flu pandemic (once called, incorrectly, the Spanish flu) killed quickly and in huge numbers, with estimates of the global death toll ranging from 50 to 100 million people. Several factors contributed to the high mortality rate: lack of antibiotics, the global disruption of World War I, and more.

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.

Influenza infects up to a billion people worldwide each year

The World Health Organization estimates that seasonal influenza causes about 1B cases annually, including 3 to 5M severe illnesses and between 290,000 to 650,000 deaths.

Major genetic shifts in flu viruses can spark global pandemics

Antigenic shift happens when two different influenza viruses infect the same host and swap genetic material. The result is a brand-new subtype of influenza which, if easily spread among people, can trigger a worldwide pandemic.

The flu is a contagious respiratory illness caused by influenza viruses

Unlike the common cold, influenza attacks suddenly with fever, body aches, and fatigue. Seasonal strains circulate worldwide, infecting up to a billion people each year and causing hundreds of thousands of deaths despite vaccines and treatments.

Learn the history and science of influenza in 'This Podcast Will Kill You'

In their flu episode, cohosts Erin Welsh and Erin Allmann Updyke unpack influenza's biology, history, and impact—explaining everything from past pandemics to modern vaccines, all with their trademark mix of science and storytelling.

The flu vaccine has evolved alongside discoveries of new virus strains

After influenza B was identified in 1940, researchers created a two-strain vaccine by 1942. The WHO later built a global surveillance system to track mutations, enabling vaccines to be updated annually to target the strains most likely to circulate.

Small genetic changes that accumulate over time force flu vaccines to be updated regularly.

Volcanoes in the 1340s likely helped trigger the Black Death

The "bubonic plague" that wiped out roughly half of Europe and Asia originated from many factors. Recent research suggests volcanic eruptions contributed as well. The "aerosol" effects of matter released from eruptions likely prompted famine and accelerated the spread of infected fleas riding on grains avoiding spoilage.

Flu spreads through droplets in the air and on surfaces

Influenza passes mainly through tiny droplets released when sick people cough, sneeze or talk. The virus can also survive briefly on surfaces, allowing it to spread when others touch contaminated objects.

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.

The bubonic plague spread in three waves over 600 years

The Black Death refers to the first wave of the plague, which swept through Europe in the 14th century and killed 25 to 50 million people. Caused by the bacterium Yersinia pestis carried by fleas (often on rats), the human toll was roughly one-third of Europe's population at the time.

Cholera went global thanks to global trade

The first cholera pandemic grew from an outbreak in India, in 1817. Scientists suggest it spread from there throughout the continent and onward to Africa, Russia and Europe through the poop of traders.

Most flu cases are treated at home, but antivirals help high-risk patients

Rest, fluids and common medicines usually ease influenza symptoms. For people at higher risk of complications, doctors may prescribe antiviral drugs, which work best when started soon after symptoms begin.

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.

Find out how prevalent the flu is at this current moment

Updated weekly, this USAFacts resource shares current data from the CDC detailing how many cases of influenza and other flu-like illnesses accounted for doctor's visits. Monitor the spread of respiratory illness during flu season with this handy resource and prepare accordingly.

'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.)

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.

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.)

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.

Annual flu shots remain the best defense against influenza

Flu vaccination typically reduces the risk of medical visits by 30 to 60% and lowers hospitalization rates by around 40%. Between 2023 and 2024, in the US alone, vaccines prevented an estimated 120,000 hospitalizations and nearly 7,900 deaths.

Environmental conditions, shifting immunity, and viral strain could help explain 2025 spike

The surge in HFMD in the summer and early fall of 2025 in the mid-Atlantic could be the result of a confluence of factors, including a more virulent strain of disease-causing virus, good environmental conditions for the virus to spread—hot, humd—and a potential immunity gap among kids due to milder HFMD outbreaks the previous year.

See how Ebola tore through Guinea, Sierra Leone, and Liberia in 2014-16.

HIV originated in Central and West Africa from a virus in chimpanzees

Researchers believe the virus crossed from chimpanzees to humans through bushmeat practices in the early 20th century, with genetic studies suggesting the most recent common ancestor of the HIV-1 M group, which is responsible for the global AIDS pandemic, emerged around 1910–1930 in Léopoldville (now Kinshasa) in the Belgian Congo.

Visualizing the genetics of SARS-CoV-2

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, began with an outbreak in Wuhan, China in December 2019, and rapidly spread worldwide in early 2020. On March 11, 2020, the World Health Organization declared COVID-19 a global pandemic, leading to widespread lockdowns, travel restrictions, and economic disruptions.

Genetic analysis suggests Anopheles mosquitoes fed on humans some 1.8 million years ago.

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.

Molecular evidence suggests the deadliest malaria parasite may be 100,000 years old.

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

New research published in 2025 upended long-held notions that the disease was introduced to the Americas by European colonizers. Evidence of a lesser-known leprosy-causing bacterium was found in ancient human remains that date back 4,000 years.

Explore this interactive visualization of illnesses known to jump from animals to people, and learn how these zoonotic diseases spread.

Measles infection, which was nearly universal during childhood in prevaccine era, was described by the Persian physician Rhazes in the 10th century as "more to be dreaded than smallpox."

Explore a technical look at the measles virus and its toll on humanity through the ages.

Measles evolved from an ancient cattle disease, branching off as recently as 3,000 years ago.

Before vaccines, there was 'variolation': what was it?

Before the technology behind vaccinations was discovered, some keen observers of medicine around the globe noticed how previous infections could impact future ones. Learn about the techniques early physicians used before they had vaccines.

Opium's history traces from religious use to mass-market commercial products

Religious or medical use of opium was present across Europe and Asia as early as 5000 BCE. By the 16th century, humanity had come to see opium as more than medicine: It was a marketable product. This perspective also defines today's relationship with opioids, highly addictive painkillers at the heart of an ongoing drug crisis.

COVID-19 vaccine breakthroughs are driving efforts toward a universal flu shot

mRNA and other technologies used for COVID-19 vaccines are being applied to influenza research. Scientists hope these advances will lead to a universal flu vaccine that protects against multiple strains and reduces the need for yearly shots.

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.

Hollywood's efficient response to the Spanish flu made it a filmmaking destination

In 1918, the Great Influenza epidemic killed more than 675,000 Americans. Los Angeles was one of the first cities to shut down movie theaters, most of which were independently owned and couldn’t afford the revenue loss. The results were twofold: the quick response meant that Hollywood could bounce back faster than other film hubs, and it also contributed to the rise of vertical integration as studios stepped in to purchase the flailing theaters.

East Asian records of auroras may date back to 10,000 BCE

Ancient texts from Japan, Babylon, and China contain accounts of auroras dating back millennia. Because auroral activity and intensity are driven by periodic ebbs and flows in solar activity, these records allow scientists to identify patterns that may help anticipate particularly dangerous future solar storms.