Ebola

The Ebola virus might not kill as many people each as TB, but it is still one of the deadliest pathogens on record and a subject in popular media since it was discovered in 1976.

Ebola can silently incubate in a person for two to 21 days, after which a person may suffer an abrupt fever and headache, according to the CDC. Joint and muscle aches, sore throat and weakness usually give way to diarrhea, vomiting and stomach pain. Some people with Ebola will have a rash, red eyes, internal and external bleeding, according to the CDC.

All four strains of the Ebola virus known to infect humans are spread through contact with blood, tissue or bodily fluids, according to the World Health Organization. The most virulent strains of Ebola kill 25 to 90 percent of people they infect.  All outbreaks of Ebola have occurred in Africa, and scientists hypothesize the virus is carried within wild animals, according to the CDC.