A few facts about Marburg virus (MARV). MARV is a hemorrhagic fever virus (filovirus). There is another species described from the same genus (Margburgvirus) called Ravn virus (RAVV). They are enveloped single stranded positive-sense RNA virus related to ebola viruses. 1/
MARV has a broad distribution range in Sub-Saharan Africa. The likely primary natural reservoir is the Egyptian fruit bat (Rousettus aegyptiacus), but the virus probably also circulates in some insectivorous bats. 2/
MARV can spill over to old world monkeys, non-human primates (chimpanzees and gorillas) and humans. Chimpanzees were at some point suspected to be the natural reservoir. MARV is extremely lethal in humans with a case fatality rate of ~50%. 3/
There have been close to 20 outbreaks of MARV recorded to date. The largest outbreak to date happened in Angola in 2004–2005 and resulted in 374 cases and 329 deaths (case fatality rate of 88%). 4/ ecdc.europa.eu/en/infectious-…
There are currently two outbreaks under way, in Tanzania and Equatorial Guinea (EQ). It is unclear at this stage whether the two are epidemiologically related. The EQ outbreak is highly concerning as cases have been recorded in densely populated areas. 5/ cdc.gov/vhf/marburg/ou…
MARV is named after the city of Marburg in Germany. In 1967 following the shipment of ~600 MARV infected green monkeys (Chlorocebus aethiops) to Germany and ex-Yugoslavia, there were three independent outbreaks (Marburg, Frankfurt and Belgrade), with 32 cases and 7 deaths. 6/
In Marburg and Frankfurt, lab workers most likely got infected through exposure of kidney cell cultures from infected monkeys. In Belgrade, a vet caught it from exposure to blood after performing an autopsy on a dead monkey 7/
The Marburg and Frankfurt outbreaks qualify as 'lab leaks' even if there was obviously no viral genetic manipulation (this was in 1967), and no nefarious intent. There are also two known lab accidents involving MARV in Russia (1988 and 1990), with no follow-up transmission. 8/