The Deadliest Disease Outbreaks in History (Including the Epidemic of Today)

Devastating disease outbreaks began in the U.S. when European settlers brought foreign illnesses overseas. Around the world, epidemics still impact communities and kill thousands. Thankfully, we’ve learned a lot since the 1600s.

These lessons should help us avoid a widespread outbreak of preventable diseases in the near future. Here’s what we know now that we didn’t know then.

1633–1634: Smallpox

Syringe on a map of Africa.

This illness led to many deaths. | Dk_photos/iStock/Getty Images

Smallpox wiped out over half of the Native American population in the 1700s. An 8-year-old boy was the first to receive the earliest version of a smallpox vaccine later that century. Following this experiment, Edward Jenner discovered that exposing individuals to a weakened live virus could protect the body against an invasion of that virus. The vaccine became so widely effective that we no longer require it. The last case of smallpox occurred in New England in 1949.

The lesson: Widespread vaccination works. It can eradicate deadly diseases.

Next: A disease that’s unfortunately still common in some parts of the world

1832–1866: Cholera

Cholera vaccination on blue trays.

Cholera is still common in some countries. |

A cholera epidemic hit New York City in 1832, killing an estimated 3,515 people. According to Mayo Clinic, cholera causes nausea, vomiting, diarrhea, and severe dehydration, plus seizures, coma, and death if other symptoms aren’t controlled. It’s unfortunately still common in regions like Haiti, Central Mexico, and Africa.

The lesson: Vigorous hand-washing — and avoiding drinking water you’re not sure about — can help you avoid the virus.

Next: Thousands still develop this disease every year in the U.S.

1906–1907: Typhoid fever

A doctor reading a book about Thypoid Fever.

Typhoid fever is easily transmitted. | Designer491/iStock/Getty Images

Mary Mallon, a cook in New York, unknowingly transmitted typhoid fever to over 100 people in 1906. She turned out to be a healthy carrier of the deadly disease — she displayed no symptoms but could give the disease to otherwise healthy people. Despite vaccines, the Centers for Disease Control and Prevention reports nearly 6,000 people still develop typhoid fever in the U.S.

The lesson: It’s possible to carry and spread an illness, even if you don’t “feel” sick.

Next: Millions died during this global pandemic in 1918.

1918: ‘Spanish’ flu

A doctor with a blue glove holds a vial.

This isn’t just a disease from ancient times. | Jarun011/iStock/Getty Images

Approximately half a million Americans — and 50 million people around the world — died of an influenza pandemic in 1918. Scientists still don’t know where the virus came from. We do know it behaved differently than most other flus, targeting young adults between 20 and 40 and killing a higher percentage of its victims. The more we learn about the virus, the more hope we have of developing effective preventive vaccines against it.

The lessons: Our understanding of diseases and how they spread has come a long way. We still have a lot more to learn.

Next: This disease still pops up due to a lack of widespread vaccinations.

1981–1991: Measles

A baby being vaccinated by a doctor.

A disease that so far has not been eliminated | Comzeal/iStock/Getty Images

A measles outbreak swept across the U.S. beginning in 1989. Unfortunately, this wasn’t the last outbreak the region suffered through. In 2000, officials announced measles had been eradicated in the U.S. But multiple outbreaks have affected many states in the past several years, mostly due to a lack of widespread vaccinations for the disease. Unlike smallpox, it doesn’t look like measles will be eliminated in America anytime soon.

The lesson: Preventable diseases don’t go away unless everyone who’s able receives a vaccine.

Next: An outbreak hit Milwaukee in 1993.

1993: Cryptosporidiosis

Water being poured from a water bottle.

Water contamination can affect people across entire states. |

A waterborne outbreak of a parasitic disease called cryptosporidiosis flooded Milwaukee, Wisconsin in 1993. Over 100 people died, and many more lost their lives due to compromised immune systems. The parasite affected one of two water treatment plants in the area, but thousands still fall ill every year due to contaminated water elsewhere.

The lesson: Personal hygiene is your best defense against all types of deadly infections.

Next: The epidemic that continues today

1980s–now: HIV/AIDS

Blood collection tube with HIV test label.

HIV and AIDS prevention comes through education and access to health care. | Dina2001/iStock/Getty Images

HIV/AIDS, first documented in the U.S. in 1981, killed almost half of its reported victims that first year. As the years went on, infections spread and took more lives. Millions of people still live with the condition today, though new cases continue to gradually decrease. Researchers continue to develop both treatments and preventive measures to decrease rates even more.

The lesson: Developing methods to treat disease improves patients’ quality of life. Prevention can help individuals avoid disease altogether.