Marburg virus

What is Marburg virus?

Marburg virus is a severe and highly contagious form of haemorrhagic fever caused by a virus from the same family - the filoviruses - as Ebola haemorrhagic fever (EHF), although it's not as deadly as its cousin.

The virus was first discovered in 1967, during simultaneous outbreaks at laboratories in the former Yugoslavia and Frankfurt and Marburg, Germany. Since 1967 sporadic small outbreaks have been reported but in 2004-5 a major outbreak in Angola led to more than 140 deaths from the Marburg virus.

Causes and risk factors of Marburg virus

The virus appears to be rare and only found in Africa where cases have occurred in Uganda, Kenya, Zimbabwe and Angola. In the natural habitat the reservoir of the virus is the Egyptian fruit bat, which is found in Africa, but how the virus jumps from animals to humans is not known. Some people have developed the disease after visiting caves where the bats are found.

Health officials linked the infection in 1967 in Europe to contact with green monkeys (or African grivets) imported from Uganda for research on a polio vaccine (and so it became known in the media as 'green monkey disease').

Once a human is infected they can pass the virus on to others through their body fluids, most commonly blood but also faeces, saliva and vomit. The virus may also possibly be spread via aerosols of tiny infected droplets produced when patients cough and splutter. However, the research suggests that sick humans don't usually generate sufficient volumes of infectious aerosols to pose a significant hazard to those around them.

Symptoms of Marburg virus

During the incubation period, which lasts between five and ten days, no symptoms are apparent. After that patients develop a sudden onset, flu-like illness with fever, chills, headache and aching muscles. Nausea and vomiting are also common.

The disease can then become increasingly damaging, causing:

• Jaundice
• Delirium
• Liver failure
• Extensive haemorrhage from multiple sites, which can give rise to bloody diarrhoea and vomiting of blood (known as heamatemesis)

Many people infected with the virus die, usually from haemorrhagic shock or liver failure. In areas where medical support is poor, the death rate can be much higher. The infection can be difficult to diagnose, because many of the initial signs are similar to those of other infectious diseases, such as malaria or typhoid fever.

Treatment and prevention of Marburg virus

There is no cure for Marburg disease. However, many patients can make a full recovery – as many as 40 per cent survive with good and early supportive care such as intravenous fluids. But this can take a long time, and some suffer from complications such as hepatitis, inflammation of the spinal cord and eye problems.

Strict hygiene measures help to prevent spread when an outbreak occurs, and an experimental vaccine is currently being tested.