What to know about Marburg virus disease

Marburg virus disease (MVD), formerly known as Marburg haemorrhagic fever, is a severe, often fatal illness in humans.

The virus causes severe viral bleeding fever in humans and has an average case fatality rate of around 50 percent, according to the World Health Organization (WHO).

Case fatality rates have varied from 24 percent to 88 percent in past outbreaks depending on virus strain and case management.

While early supportive care with rehydration, and symptomatic treatment improves survival, there no licensed treatment yet proven to neutralize the virus.
However, a range of blood products, immune therapies and drug therapies are currently under development.
Rousettus aegyptiacus, fruit bats of the Pteropodidae family, are considered to be natural hosts of Marburg virus.
The Marburg virus is transmitted to people from fruit bats and spreads among humans through human-to-human transmission.

Marburg virus disease was initially detected in 1967 after simultaneous outbreaks in Marburg and Frankfurt in Germany and in Belgrade, Serbia.
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 imported from Uganda. Subsequently, outbreaks and sporadic cases have been reported in Angola, the Democratic Republic of the Congo, Kenya, South Africa (in a person with recent travel history to Zimbabwe) and Uganda.
In 2008, two independent cases were reported in travellers who had visited a cave inhabited by Rousettus bat colonies in Uganda.

Read also: Marburg virus: WHO mobilises experts as Ghana prepares for outbreak

Transmission
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 contaminated with these fluids.

Health-care workers have frequently been infected while treating patients with suspected or confirmed MVD.
This has occurred through close contact with patients when infection control precautions are not strictly practiced.
Transmission via contaminated injection equipment or through needle-stick injuries is associated with more severe disease, rapid deterioration, and, possibly, a higher fatality rate.

Symptoms
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 two and seven 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 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.