Ravn virus is one of two viruses classified in the species Marburg marburgvirus within the genus Marburgvirus (family Filoviridae). It is a negative‑sense, single‑stranded RNA virus with a genome of about 19 kilobases and is closely related to but genetically distinct from Marburg virus. Both viruses cause Marburg virus disease, a severe hemorrhagic fever characterized by sudden onset of high fever, malaise, gastrointestinal symptoms and bleeding.
Discovery, Taxonomy and Biology
The virus was first isolated in 1987 from a fatal case of hemorrhagic fever in a Danish traveler who had visited Kitum Cave on Mount Elgon in Kenya; the isolate was named Ravn virus after the patient’s surname. Initially considered a strain of Marburg virus, genomic analysis showed approximately 20 % nucleotide divergence, leading to recognition of Ravn virus as a separate virus within the species. Like Marburg virus, Ravn virus encodes seven structural proteins—nucleoprotein (NP), VP35, VP40, glycoprotein (GP), VP30, VP24 and the RNA‑dependent RNA polymerase (L)—and forms filamentous, enveloped virions. The Egyptian fruit bat (Rousettus aegyptiacus) is believed to serve as the natural reservoir; viral RNA and antibodies have been detected in bat populations, and identical sequences have been recovered from bats in Uganda. Human infection occurs through exposure to bat secretions in caves or mines or through contact with infected animals or patients. Clinical presentation and case fatality rates of Ravn virus infection are indistinguishable from those of Marburg virus disease, ranging from 25 % to over 80 %. There are no specific antiviral treatments; management relies on supportive care and strict infection control.
Outbreaks and Epidemiology
After the initial 1987 case in Kenya, Ravn virus was implicated in several subsequent outbreaks. Retrospective analysis of the 1998–2000 outbreak among gold miners in Durba, Democratic Republic of the Congo, revealed co‑circulation of Marburg and Ravn viruses; genetic sequencing showed that many cases were attributable to Ravn virus. A cluster of Ravn virus cases occurred in Uganda in 2007, associated with a mine inhabited by Egyptian fruit bats. Further sporadic cases and small outbreaks were reported in Uganda in 2012 and 2017. Surveillance of bat colonies in Kitaka and Python caves in Uganda found Ravn virus RNA in a subset of Rousettus aegyptiacus bats, supporting the reservoir hypothesis. There is no evidence of sustained human‑to‑human transmission outside outbreak settings; transmission occurs via direct contact with blood or bodily fluids of infected individuals or through exposure to aerosolized excreta in bat caves. Public health responses focus on rapid identification, isolation, barrier nursing, safe burial and community education to reduce bat exposure.
Ravn virus, together with Marburg virus, represents the Marburgvirus genus and poses a significant threat due to its ability to cause lethal outbreaks. Continued monitoring of bat reservoirs and implementation of infection control measures are essential to prevent future outbreaks.
Related Terms: Marburg Virus, Zaire Ebolavirus, Sudan Ebolavirus, Bundibugyo Ebolavirus, Hantaan Virus