9. Rabies
No longer a significant threat in the United States, rabies is still a deadly problem in other areas of the world. Rabies causes “tens of thousands” of deaths every year in countries in Africa and Asia, according to the WHO. Approximately two people die yearly in the U.S. from the disease, which is transmitted to humans through the saliva of infected animals, particularly dogs.
The initial symptoms of rabies can be hard to detect in humans, as they mimic that of the flu and include general weakness, discomfort and fever. But as the disease progresses, patients may experience delirium, abnormal behavior, hallucinations and insomnia, according to the Centers for Disease Control and Prevention (CDC). To date, fewer than 10 people who have contracted rabies and started to exhibit symptoms have survived.
However, a rabies vaccine does exist and is usually very effective in both preventing infection with the virus and treating infected individuals before they begin to show symptoms.
10. Pneumonia
Pneumonia might not conjure up the same dread as diseases like rabies or smallpox, but this lung infection can be deadly, especially for those older than 65 or younger than 5.
The disease can be caused by bacteria, a virus or a combination of both, according to Dr. Amesh Adalja, an infectious-disease specialist and a senior associate at the University of Pittsburgh Medical Center’s Center for Health Security. A person can also get pneumonia from a fungal infection, parasites or reactions to certain medicines, Adalja told Live Science in September 2016.
In 2017, there were 49,157 deaths from pneumonia in the United States, according to the CDC.