Marburg virus disease (MVD) is a rare but severe hemorrhagic fever which affects both people and non-human primates.
MVD is caused by the Marburg virus, a genetically unique zoonotic (or animal-borne) RNA virus of the filovirus family.
Marburg virus disease was initially detected in 1967 after simultaneous outbreaks in Marburg and Frankfurt in Germany; and in Belgrade, Serbia.
Marburg and Ebola viruses are both members of the Filoviridae family (filovirus).
Though caused by different viruses, the two diseases are clinically similar.
Both diseases are rare and have the capacity to cause outbreaks with high fatality rates.
Two large outbreaks that occurred simultaneously in Marburg and Frankfurt in Germany, and in Belgrade, Serbia, in 1967, led to the initial recognition of the disease.
The outbreak was associated with laboratory work using African green monkeys (Cercopithecus aethiops) imported from Uganda.
Subsequently, outbreaks and sporadic cases have been reported in Angola, the Democratic Republic of the Congo, Kenya, South Africa and Uganda.
In March 2023, Tanzania recorded its first-ever cases of Marburg Virus Disease.
Transmission
Initially, human MVD infection results from prolonged exposure to mines or caves inhabited by Rousettus bat colonies.
Marburg spreads through human-to-human transmission via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids.
Burial ceremonies that involve direct contact with the body of the deceased can also contribute in the transmission of Marburg.
People remain infectious as long as their blood contains the virus.
Signs and Symptoms of Marburg Virus Disease
The incubation period (interval from infection to onset of symptoms) varies from 2 to 21 days.
Illness caused by Marburg virus begins abruptly, with high fever, severe headache and severe malaise.
Muscle aches and pains are a common feature. Severe watery diarrhoea, abdominal pain and cramping, nausea and vomiting can begin on the third day.
Diarrhoea can persist for a week.
The appearance of patients at this phase has been described as showing “ghost-like” drawn features, deep-set eyes, expressionless faces, and extreme lethargy.
In the 1967 European outbreak, non-itchy rash was a feature noted in most patients between 2 and 7 days after onset of symptoms.
Many patients develop severe haemorrhagic manifestations between 5 and 7 days, and fatal cases usually have some form of bleeding, often from multiple areas.
Fresh blood in vomitus and faeces is often accompanied by bleeding from the nose, gums, and vagina.
Spontaneous bleeding at venepuncture sites (where intravenous access is obtained to give fluids or obtain blood samples) can be particularly troublesome.
During the severe phase of illness, patients have sustained high fevers.
Involvement of the central nervous system can result in confusion, irritability, and aggression.
Orchitis (inflammation of one or both testicles) has been reported occasionally in the late phase of disease (15 days).
In fatal cases, death occurs most often between 8 and 9 days after symptom onset, usually preceded by severe blood loss and shock.
Treatment and vaccines
Currently there are no vaccines or antiviral treatments approved for MVD.
However, supportive care – rehydration with oral or intravenous fluids – and treatment of specific symptoms, improves survival.
There are monoclonal antibodies (mAbs) under development and antivirals e.g. Remdesivir and Favipiravir that have been used in clinical studies for Ebola Virus Disease (EVD) that could also be tested for MVD or used under compassionate use/expanded access.
In May 2020, the EMA granted a marketing authorisation to Zabdeno (Ad26.ZEBOV) and Mvabea (MVA-BN-Filo). against EVD .
The Mvabea contains a virus known as Vaccinia Ankara Bavarian Nordic (MVA) which has been modified to produce 4 proteins from Zaire ebolavirus and three other viruses of the same group (filoviridae).
The vaccine could potentially protect against MVD, but its efficacy has not been proven in clinical trials.
