Ebola virus overview and transmission facts

Ebola is a virus with a high fatality rate that was first identified in 1976 in Africa, specifically in northern Zaire (now the Democratic Republic of the Congo) and southern Sudan (now South Sudan). The virus is named after the Ebola River.

There are five subspecies of the Ebola virus. Four of these strains can cause severe illness in both humans and animals, while the Reston virus affects some animals but not humans. Ebola is considered extremely infectious because a very small amount can cause illness, though it is moderately contagious as it is not transmitted through the air.

Human infection occurs through contact with the body fluids of an infected person, contaminated objects, or by butchering infected animals. Symptoms typically include fever, weakness, aches, diarrhea, vomiting, and stomach pain, with an incubation period ranging from two to 21 days. While generally not transmissible from asymptomatic individuals, the virus has been found in the semen of recovered men, suggesting potential transmission through contact with semen.