Rapid detection of outbreaks is critical. That's why the CDC partnered with Uganda on a pilot program to speed things up. Above: Workers at an Ebola emergency response center in Sierra Leone during the outbreak that began in 2014.
David P. Gilkey/NPR
This banner is displayed at the Institute of Lassa Fever Research and Control in Irrua Specialist Teaching Hospital in Irrua, Edo State, midwest Nigeria.
Pius Utomi Ekpei /AFP/Getty Images
The mystery disease in South Sudan has not been identified but is known to cause fever and unexplained bleeding. Above: an image of another hemorrhagic fever, Marburg virus, made with an electron microscope and then colorized.