Going Viral: The Deadliest Viruses in the World

Man with a virus

These viruses can cause serious problems for your health. | iStock.com

Viruses: They’re not just something that infects your smartphone. Millions, if not billions, of people live alongside deadly viruses to this day in communities around the world. Though we’ve made huge strides in eradicating certain viral infections through vaccination, you can probably name a virus or two that’s wreaking havoc in some part of the world.

Names like Ebola, Zika, or dengue are likely to come to mind. But for the majority of Americans, a viral infection is more likely to come in the form of a cold. Or perhaps the flu every so often. While those can throw your world into flux for a few days, they’re typically not long-lasting or deadly. You get sick. You rest up. And you get over it.

Some viruses, however, you don’t simply “get over.” If you get a serious one? It can, and will, kill you. A quick scan through a history book reveals that humanity has had its struggles with serious viral and bacterial adversaries. Disease played a big role in the downfall of many civilizations, for example, and nearly stopped humanity in its tracks on several occasions. Take the bubonic plague, for example. Or the famous flu outbreak of 1918 (more on that later).

A simple viral infection may not seem like a big deal, but without modern medicine on your side, you’d be singing a different tune. Viruses are lethal and have killed hundreds of millions over the centuries. Here are 10 of history’s deadliest viruses.

1. Rabies

A rabies vaccine prepared for use

Believe only wild animals get rabies? Think again. | Ulet Ifansasti/Getty Images

These days, rabies isn’t much of a concern. We even trivialize and laugh about it, as seen in TV shows like Seinfeld and The Office. But rabies used to be a death sentence. And throughout generations, it’s killed millions of people. Even though we have a vaccine, the virus still kills more than 50,000 people every year. That amounts to more than 100 people who are killed every day, The Independent reports, mostly because they can’t afford the vaccine.

2. Marburg virus

A researcher works with virus samples

This virus can easily kill you. | Thomas Lohnes/AFP/Getty Images

Marburg virus, also known as Marburg hemorrhagic fever, isn’t exactly a widespread virus. But it is incredibly deadly. In certain outbreaks, the death rate has been as high as 88%. It’s somewhat similar to Ebola —  it actually shares a sub-class within the strata of virus families. It’s typically transmitted via direct contact with blood or other bodily fluids.

3. Yellow fever

Mosquito sucking blood on human skin

Mosquitos spread this virus. | iStock.com/auimeesri

Most of us are familiar with yellow fever, a virus typically spread by mosquitos. We have vaccines that are effective and affordable, and lots of progress has been made in recent years toward eradicating it. Yet, hundreds of thousands of people still contract yellow fever every year, and the World Health Organization says 30,000 are killed.

4. HIV

Blood collection tube with HIV test label

You’ve definitely heard of this one. | iStock.com/dina2001

HIV is one of the most familiar viruses to the average American today. Outbreaks in the 1980s and ’90s killed a lot of people, and though the virus is still out there, we have effective treatments allowing people to live with it. HIV, of course, is associated with AIDS, which still kills more than a million people every year. As of today, more than 36 million people worldwide are living with HIV.

5. Spanish flu

Nurses care for victims of a Spanish influenza epidemic outdoors amidst canvas tents

Nurses care for victims of a Spanish influenza epidemic outdoors amidst canvas tents. | Hulton Archive/Getty Images

We could put “influenza” here, but we’re going to run with the deadliest version — the Spanish flu. According to a report from Stanford, this particular strain of influenza killed more people in one year, 1918, than the bubonic plague did when it wiped out a huge percentage of the European population in the 1300s. Total deaths attributed to the Spanish flu are estimated at between 50 and 100 million.

6. Ebola

A Liberian woman disinfecting in the midst of an Ebola outbreak

Ebola gave everyone quite a scare. | Dominique Faget/Getty Images

There was a serious Ebola outbreak just a few years ago, as most of us remember. Though Ebola is largely relegated to small geographic areas in western Africa, it’s a frightening virus that is extremely lethal. Reuters says the most recent outbreak killed more than 10,000, but the virus isn’t gone. It’s spread by contact with bodily fluids, and the fatality rate for those afflicted is roughly 50%.

7. Dengue

A Dengue Fever sufferer is treated at a hospital

This young girl has dengue fever. | Dimas Ardian/Getty Images

Yet another tropical, mosquito-spread virus, dengue fever affects billions of people who live in at-risk areas. The virus has spread to more than 100 countries, and hundreds of millions of cases are diagnosed every year. Severe epidemics continue to occur, and though a vaccine recently came onto the market, dengue is still ravaging communities around the world.

8. Smallpox

Vials of smallpox vaccine sit on a counter

Smallpox used to kill millions. | Chris Livingston/Getty Images

Smallpox has been largely eradicated. For that reason, we don’t typically vaccinate against it anymore. But before the vaccine was developed, smallpox killed millions. Fifty million people per year contracted the virus, with hundreds of thousands dying as a result. It’s an ancient virus, National Geographic reports, with the earliest provable signs showing up in India or Egypt 3,000 years ago. Even some Egyptian mummies show evidence of Smallpox.

9. Hepatitis

Hepatitis written on a clipboard

Hepatitis is not a disease you want to contract. | iStock.com/Zerbor

Hepatitis isn’t too much of an issue in modern America. It comes in a few different forms and is typically treatable. But make no mistake — it’s deadly. Hepatitis B, in particular, kills 686,000 people every year. Hepatitis C, also, is a quiet but efficient killer. The CDC says nearly 20,000 people died as a result of hepatitis C contraction in 2014 alone.

10. Measles

A college student receives a Measles vaccine

Measles is no longer a huge threat, but it could come back. | Mark Kegans/Getty Images

If you haven’t heard, measles is making a comeback. Today, measles isn’t a serious threat — mostly because the majority of people are vaccinated. But the recent fad of forgoing these shots is bringing it back. Prior to widespread vaccination in 1980, the WHO says that measles killed roughly 2.6 million people every year.