Marburg virus disease

Causative agent

Marburg virus disease (MVD), formerly known as Marburg haemorrhagic fever, is a severe, often fatal illness in humans. It is caused by the Marburg virus that belong to the Filoviridae family (filovirus). The reservoir host of Marburg virus is the fruit bat Rousettus aegyptiacus. The average case fatality rate of MVD is about 50% but that could be varied from 24% to 88% depending on virus strain and case management.

MVD was initially recognized in 1967, when two outbreaks occurred simultaneously in laboratories in Marburg and Frankfurt in Germany, and in Belgrade, Serbia. The outbreaks were 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 (a case with recent travel history to Zimbabwe), Uganda, Guinea, Ghana and Equatorial Guinea.

Clinical features

Symptom onset is sudden with high fever, severe headache and severe malaise. Muscle aches and pains are commonly seen. Patients may have severe watery diarrhoea, abdominal pain, cramping, nausea and vomiting on the third day after onset of symptoms. Diarrhoea can persist for a week and the patient may present with deep-set eyes, expressionless faces and extreme lethargy. A non-itchy rash was found between 2 and 7 days after onset of symptoms in most patients in the 1967 European outbreak.

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. Patients may present with sustained high fevers at the severe phase of illness. Central nervous system could be involved resulting in confusion, irritability, and aggression. Orchitis has been reported occasionally in the late phase of disease.

Death usually occurs between 8 and 9 days after symptom onset in fatal cases, usually preceded by severe blood loss and shock.

Mode of transmission

MVD infection originally results from prolonged exposure to mines or caves inhabited by Rousettus bat colonies. Once an individual is infected with the virus, Marburg virus can spread through human-to-human transmission via direct contact, through broken skin or mucous membranes, with the blood, secretions, organs or other body fluids of infected people, and with surfaces and materials contaminated with these fluids such as bedding and clothing. Healthcare workers can also be infected via close contact while taking care of infected patients.

In addition, burial ceremonies that involve direct contact with the body of the deceased can contribute in the transmission of MVD. People remain infectious as long as their blood contains the virus.

Incubation period

It ranges from 2 to 21 days.

Management

Currently, there is no specific vaccine or antiviral treatment approved for MVD. Supportive care is the mainstay of management, including rehydration with oral or intravenous fluids.

Prevention

To prevent the infection, the public should adopt the following measures when travelling to places affected by MVD:

• Perform hand hygiene frequently, especially before and after touching the mouth, nose or eyes; before eating; after using the toilet, after touching public installations such as handrails or door knobs; or when hands are contaminated by respiratory secretion after coughing or sneezing. Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with either a clean cotton towel or a paper towel. If hand washing facilities are not available, or when hands are not visibly soiled, hand hygiene with 70 to 80% alcohol-based handrub is an effective alternative.
• Avoid close contact with feverish or ill persons, and avoid contact with patients’ blood and body fluids, and objects contaminated with blood or body fluids of patients.
• Avoid contact with wild animals especially fruit bats and sick animals.
• Avoid visiting areas where bats are known to inhabit.
• Cook food thoroughly before consumption.
• Travellers should seek medical advice promptly if they become ill within 21 days after returning from affected areas and inform doctor of recent travel history.