The Ebola virus first appeared in humans during a massive African outbreak of the Ebola virus disease in 1976. This initial outbreak was, according to the World Health Organization (WHO), the most widespread and complicated outbreak ever reported.
Humans catch the Ebola virus through initial exposure from infected primates. The virus is then passed from human to human through contact with the bodily fluid (saliva, blood, vomit, feces, urine and sweat) of an infected person; symptoms will then appear within 20 days, though they typically appear sooner. According to the WHO, the 2014 Ebola virus disease outbreak is the largest and most complex outbreak since the initial 1976 outbreak.