These viruses are filamentous in structure and are therefore known as filoviruses. Marburg virus and Ebola virus belong to this group. Infections with some of these viruses have a very high case-fatality ratio (e.g. Zaire ebolavirus), other are seemingly non-pathogenic (e.g. Reston ebolavirsus). Epidemics with human pathogenic filoviruses have become more common in the beginning of the 21st Century and the risk is not negligible that the infections become endemic, at least in Central Africa.
In the last years, several new filoviruses were detected in bat and fish species. Lloviu virus was discovered in 2010 in Schreiber’s long fingered bats (Miniopterus schreibersii) found dead in a cave (the dead bat was already found in 2002), the so-called Cueva del Lloviu, Asturias, northern Spain. Later similar discoveries were made in caves in France,Portugal and Hungary. In 2018, Bombali virus sequences were discovers in bats from Sierra Leone, Guinea and Kenya and the virus is considered to be a new ebolavirus species. Měnglà dianlovirus (diān is the Chinese abbreviation for Yunnan) was found in Rousettus bat in Mengla County, Yannan province in China in January 2019.Fish-derived filoviruses constitute members of two new genera: striavirus and thamnovirus. At present it is uncertain if these new virusses are pathogenic for the concerned animal species. These new filoviruses have not been cultured yet, only their RNA genome has been sequenced. No human infections or human disease have been detected (yet) and since no isolates are available, their zoonotic or pathogenic potential cannot be tested.