The Most Dangerous Diseases You Can Get on Earth

By Hristina Byrnes Published Jul 31, 2:00PM EDT

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The Most Dangerous Diseases You Can Get on Earth — © Matt Cardy / Getty Images News via Getty Images

Humans have been fighting disease since long before our genus evolved into Homo sapiens. The most recent example is COVID-19. Though the latest variant of the virus that causes the disease is very contagious, its fatality rate is relatively low in comparison with pathogens. (Here’s how COVID fatalities compare with those of other diseases.)

Antibiotics, vaccines, and antiviral drugs have been effective in preventing infections from spreading widely. Smallpox, for example, has been eradicated. However, as humans and our immune systems evolve, so do deadly pathogens. Some, such as Ebola, have jumped from animals to humans in recent decades, causing large outbreaks.

To determine the deadliest pathogens on Earth, 24/7 Tempo ranked viruses, bacteria, amoebas, and other potentially lethal pathogens according to their fatality rates in humans using information from Live Science and CBS News. Diseases with causes that are yet to be determined were not considered.

Click here to see the deadliest pathogens on earth

The mortality rate for any disease varies depending on access to vaccines and medical help. Some of these pathogens on the list – such as MERS or tuberculosis – spread from person to person. Others come from infected substances – even water – or from animals or microscopic organisms. (These are the 20 worst epidemics and pandemics in history.)

22. Tuberculosis
> Mortality rate: 15.0%
> Type of pathogen: Bacteria

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22. Meningococcal meningitis
> Mortality rate: 15.0%
> Type of pathogen: Bacteria

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17. Smallpox
> Mortality rate: 30.0%
> Type of pathogen: Virus

Crimean-Congo Hemorrhagic Feve... by NIAID

Crimean-Congo Hemorrhagic Feve... (CC BY 2.0) by NIAID

17. Crimean-Congo hemorrhagic fever
> Mortality rate: 30.0%
> Type of pathogen: Virus

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17. Eastern equine encephalitis
> Mortality rate: 30.0%
> Type of pathogen: Virus

17. Invasive listeria
> Mortality rate: 30.0%
> Type of pathogen: Bacteria

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17. Staphylococcus aureus
> Mortality rate: 30.0%
> Type of pathogen: Bacteria

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Aspergillosis,angioinvasive by Atlas of Pulmonary Pathology

Aspergillosis,angioinvasive (CC BY-SA 2.0) by Atlas of Pulmonary Pathology

16. Invasive aspergillosis
> Mortality rate: 30.2%
> Type of pathogen: Fungus

15. Vibrio illness
> Mortality rate: 34.2%
> Type of pathogen: Bacteria

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14. MERS (Middle East Respiratory Syndrome)
> Mortality rate: 34.4%
> Type of pathogen: Virus

Hantavirus (CC BY 2.0) by Joakim Poromaa Helger

13. Hantavirus
> Mortality rate: 36.0%
> Type of pathogen: Virus

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12. Baylisascariasis
> Mortality rate: 38.5%
> Type of pathogen: Parasite

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11. Glanders
> Mortality rate: 40.0%
> Type of pathogen: Bacteria

Tonkin snub-nosed monkeys (Rhinopithecus avunculus) by Quyet Le

Tonkin snub-nosed monkeys (Rhinopithecus avunculus) (CC BY-SA 2.0) by Quyet Le

10. Monkey B Virus
> Mortality rate: 42.0%
> Type of pathogen: Virus

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African Trypanosome (CC BY 2.0) by Ed Uthman

9. African trypanosomiasis
> Mortality rate: 42.5%
> Type of pathogen: Parasite

Marburg Virus Particles (CC BY 2.0) by NIAID

7. Marburg virus
> Mortality rate: 50.0%
> Type of pathogen: Virus

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7. Ebola virus
> Mortality rate: 50.0%
> Type of pathogen: Virus

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CSIRO ScienceImage 1718 The Hendra Virus by CSIRO

CSIRO ScienceImage 1718 The Hendra Virus (CC BY 3.0) by CSIRO

6. Hendra virus
> Mortality rate: 57.0%
> Type of pathogen: Virus

5. Bird flu
> Mortality rate: 60.0%
> Type of pathogen: Virus

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Nipah Virus Particles (CC BY 2.0) by NIAID

4. Nipah virus
> Mortality rate: 75.0%
> Type of pathogen: Virus

IMG_4321 (CC BY 2.0) by Andy Blackledge

3. Naegleria fowleri (brain-eating amoeba)
> Mortality rate: 95.0%
> Type of pathogen: Amoeba

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Balamuthia mandrillaris (cyst) by Yamanouchi

Balamuthia mandrillaris (cyst) (CC BY 4.0) by Yamanouchi

2. Balamuthia encephalitis
> Mortality rate: 98.0%
> Type of pathogen: Amoeba

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1. Rabies
> Mortality rate: 99.9%
> Type of pathogen: Virus

About the Author Hristina Byrnes →

Hristina Byrnes is the editor of 247Tempo.com, where she handles the site's assignments and editing. She holds a master's degree in journalism from Columbia University, which she earned in 2012, and she specializes in translating complex health data research into engaging, accessible stories for a general audience.

When she's not poring over the latest data sets or brainstorming story ideas, you can find Hristina watching tennis, playing tennis with her son, or trying to get her daughter into tennis.