Marburg virus: what you need to know about this pathogen cousin of Ebola

View of Marburg virus particles under an electron microscope. We see the typical structure of filoviruses, as well as the characteristic filaments in the form of hooks. Expansion 100,000x. Centers for Disease Control and Prevention

Text by: Pierre Fesnien Follow

8 min

Tanzania announced on Tuesday (March 21st) the death of five people from the Marburg virus. Last January, 11 people also lost their lives to the disease in Equatorial Guinea. RFI takes stock of what you need to know about this virus cousin of Ebola and particularly dangerous for humans.


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  • First case detected in Europe in 1967

Paradoxically, while the various outbreaks of Marburg virus have been observed in Africa, the first cases have been detected in Europe. It was in Marburg in Germany, hence the name given to the virus, in Frankfurt and Belgrade in the former Yugoslavia, that the first cases appeared simultaneously in 1967. These were researchers who had taken samples from green monkeys imported from Uganda probably during the incubation period. In the Behring laboratory in Marburg, 31 laboratory technicians are infected and seven of them die from the virus.

  • A lethal and contagious virus

Like Ebola, Marburg virus is part of the filovirus family and its lethality remains very high and varies from 24% to 88% depending on the virus strain and case management, reports the World Health Organization. On average, the fatality rate of the disease is around 50%.

Originally, the virus was transmitted from animals to humans. "We know well the reservoir of the Marburg virus which is a large bat, the Egyptian fruit bat, which is present in the regions of West Africa, in mountainous regions, and East Africa," explained to RFI Professor Denis Malvy, infectiologist at the University Hospital of Bordeaux. The animal that nests in wet caves or mines on the continent can transmit the virus to primates or humans following prolonged exposure to their fluids or feces. Monkeys and pigs can also carry the virus and transmit it to humans.

The main risk of transmission, however, remains human-to-human. "Marburg is transmitted in the same way as Ebola, by human-to-human contact when a person is febrile or symptomatic," explains Professor Denis Malvy. Human-to-human contamination results from "direct contact with blood, secretions, organs or body fluids of infected persons, or with surfaces and materials (e.g. sheets or clothing) contaminated with these liquids," says the WHO.

Conditions that mean that if the disease remains contagious, its reproduction rate is relatively low. A patient infects on average one to two people, which is much less for example than the Delta variant of Covid-19 whose reproduction rate has climbed to 6.6. This is explained by the need for prolonged exposure to a patient and his body fluids to be contaminated with the Marburg virus.

  • Symptoms similar to Ebola

The incubation period ranges from 2 to 21 days and the symptoms of Marburg are so similar to those of Ebola which is sometimes complicated to make a diagnosis. The disease sets in suddenly, with high fever, severe headaches and severe malaise. Muscle pain is a common manifestation. Profuse watery diarrhea, abdominal pain and cramps, nausea and vomiting may appear on the third day. At this stage, patients are often described as having "the appearance of ghosts, with deeply sunken eyes, an expressionless face and extreme lethargy," details the WHO. Between the fifth and seventh day, many patients develop severe bleeding manifestations that can lead to death. In fatal cases, death usually occurs nine days after the onset of symptoms and is preceded by severe blood loss.

  • Outbreaks of infections that are still appearing in Africa

For the first time, an outbreak appeared in Tanzania which confirmed on Wednesday 22 March the death of five people. Three patients are hospitalized and 161 contacts are being followed by authorities. "There is no reason to panic or interrupt economic activities ... We have everything we need to control this contagious disease " said Tanzanian Health Minister Ummy Mwalimu. Previously, Equatorial Guinea was first affected by the virus in January and February 2023, with eleven deaths.

Most often, as was the case in Equatorial Guinea, the foci of infections are fairly quickly contained. "I believe that the Ebola experience indeed allows national epidemic response teams to better manage and control. After for Marburg, the R0 is not very high, on average one person infects two other people. This makes it possible to put a response in place and control more quickly, explains Dr. Eric D'Ortenzio, epidemiologist in the emerging infectious diseases division of the ANRS. I think experience plays a huge role in these countries and now there are strategies to isolate cases and go and trace and isolate contacts. ».

So far, all outbreaks of infections have appeared in Africa for the simple reason that the Egyptian fruit bat, considered the host animal of the virus, is endemic to West and East Africa. The few cases reported in Europe or the United States were travellers returning from Africa. Compared to Ebola (11,300 deaths for 28,600 cases recorded between 2013 and 2016, editor's note), the main outbreaks of Marburg virus disease have caused relatively few deaths. The most virulent occurred between 1998 and 2000 in the Democratic Republic of the Congo and in 2005 in Angola, causing 154 and 374 deaths respectively.

  • More and more frequent epidemics?

With cases in Uganda in 2017, Guinea in August 2021, Ghana in July 2022, Equatorial Guinea in January and February 2023 and most recently in Tanzania, outbreaks of Marburg virus disease seem to be more frequent in recent years.


Emergences, there are a little all the time, the virus circulates in these areas, it is present in animals. It is believed that the reservoir is the bat so when there is contact with humans, there is a risk. Overall, on the emergences, the accentuation of livestock, agricultural areas, deforestation, these are contributing factors, analyzes Dr. Eric D'Ortenzio. In any case, over the last twenty years, we have witnessed somewhat more frequent emergence phenomena, particularly in areas of Central Africa, in forest areas, and there is probably a link, even if we cannot say it with certainty, with human activities. " continues the epidemiologist.

  • A dangerous disease, but not very virulent epidemics

The Marburg virus is often presented as less dangerous than Ebola, but the reality is actually more complex. "If you look at the case fatality rates in Marburg, which range from 24 to 88 percent depending on the epidemic. 88% case fatality is unheard of. In terms of clinical severity, the risk of severe form and death is equivalent to Ebola, after in terms of control, one actually has the impression that the Marburg epidemics are a little less intense and more quickly contained. There may be an effect on the transmission factors of the virus, but we still have little hindsight," explains Dr. Eric D'Ortenzio.

The ongoing epidemic in Tanzania is in any case no more worrying than what has been observed before. "It's a bit the same type of alert that was observed in Equatorial Guinea a few weeks ago. We have to be careful, but there is no particular concern. The only risk I see is that it is very close to the border with Uganda, so we must be careful at border crossings to prevent patients carrying the virus from spreading the disease, "warns the epidemiologist.

  • What treatment?

There is currently no treatment for Marburg virus disease. Medications can treat symptoms, but not the virus itself. Appropriate management, including oral or intravenous rehydration, can greatly improve patients' chances of survival.

Unlike Ebola, no vaccine has yet emerged to protect people from Marburg virus disease, but five vaccine candidates are currently in the testing phase. Two of them are more advanced, and the scientific community had decided to launch an evaluation phase in Equatorial Guinea. "I think discussions could soon resume to include Tanzania in this vaccine evaluation that is essential in times of epidemic to demonstrate clinical efficacy in terms of disease prevention," says Dr. Eric D'Ortenzio.

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