The Centers for Disease Control and Prevention (CDC) defines Ebola as a hemorrhagic fever, which is caused by an infection with one or more of the four strains of the Ebola virus known to be infectious to humans.

Ebola is an infectious and generally fatal disease marked by fever and severe internal bleeding. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission via infected bodily fluids like saliva, blood, semen, sweat, tears urine and more.

Ebola first came onto the medical radar in the 1976, and was named after a river in the Democratic Republic of Congo (formerly Zaire), near where the disease was first observed. Ebola first appeared in 1976 in 2 simultaneous outbreaks, one in Nzara, Sudan, and the other in Yambuku, Democratic Republic of Congo.

Outbreaks of Ebola have occurred sporadically throughout Africa since its discovery. However, the recent spike in global travel has caused an increase in media coverage of the disease. The current outbreak in West Africa, (first cases reported in March 2014), is the largest and most complex Ebola outbreak since the Ebola virus was first discovered in 1976. There have been more cases and deaths in this outbreak than all others combined.

Certain groups have had higher rates of infection. Health-care workers have frequently been infected while treating patients with suspected or confirmed Ebola. This has occurred through close contact with patients when infection control precautions are not strictly practiced. Burial ceremonies in which mourners have direct contact with the body of the deceased person can also play a role in the transmission of Ebola.

It is important to note that people remain infectious as long as their blood contains the virus.