What "germ" or environment has caused ebola?

Ebola …virus: Ebola is an acute hemorrhagic viral disease, with its first known case appearing in 1976 in simultaneous outbreaks in Nzara, Sudan, and Yambuku, Democratic Republic of Congo (WHO). It takes its name from the Ebola River near the latter Congolese village. It's generally fatal disease marked by fever and severe internal bleeding, spread through contact with infected body fluids by a filovirus

Filoviridae: Ebola is a filovirus (Filoviridae). The genomic fossils of filoviruse family that impact mammals have likely existed tens of millions of years. Viruses mutate over time. The first recognized Ebola outbreak was in 1976. The current strain of RNA virus that is affecting West Africa is the Ebolavirus Zaire.

A virus: Ebola is a virus which infects the body by entering cells and taking over the reproductive machinery; reproducing the virus thousands of times per cell and releasing these into the body to do the same thing in other cells. It started in Central West Africa and obviously there has been an unknown change in that environment which led to the current spread.