Ebola hemorrhagic fever is a disease caused by one of five different Ebola viruses. Four of the strains can cause severe illness in humans.

More new cases of Ebola have been confirmed in Africa after authorities declared a resurgence of the virus in February.

The cases represent a flare-up of the 2018-20 epidemic, which killed more than 2200 people before it was declared over last June.

Ebola hemorrhagic fever is a disease caused by one of five different Ebola viruses.Four of the strains can cause severe illness in humans and animals. The fifth, Reston virus, has caused illness in some animals, but not in humans.

The first human outbreaks occurred in 1976, one in northern Zaire (now Democratic Republic of the Congo) in central Africa: and the other, in southern Sudan (now South Sudan).

The virus is named after the Ebola River, where it was first recognised in 1976, according to the Centers for Disease Control and Prevention (CDC).Ebola is extremely infectious but not extremely contagious.It is infectious, because an infinitesimally small amount can cause illness. Laboratory experiments on nonhuman primates suggest that even a single virus may be enough to trigger a fatal infection.

Ebola is considered moderately contagious because the virus is not transmitted through the air.

Humans can be infected by other humans if they come in contact with body fluids from an infected person or contaminated objects from infected persons.

Humans can also be exposed to the virus, for example, by butchering infected animals.