What is the Marburg virus and how dangerous is it?

An outbreak of Marburg virus has killed at least eight people in Rwanda.

The highly-infectious disease is similar to Ebola, with symptoms including fever, muscle pains, diarrhoea, vomiting and, in some cases, death through extreme blood loss.

Hundreds of people have died from the virus in recent years, almost all in Africa.

According to the World Health Organization (WHO), on average, the Marburg virus kills half of the people it infects, with previous outbreaks killing between 24% and 88% of patients.

The virus was first identified in 1967 after 31 people were infected and seven died in simultaneous outbreaks in Marburg and Frankfurt in Germany, and Belgrade in Serbia.

The outbreak was traced to African green monkeys imported from Uganda.

But the virus has since been linked to other animals.

Among humans, it is spread mostly by people who have spent long periods in caves and mines populated by bats.

In recent years, there have also been outbreaks of the Marburg virus in:

• Equatorial Guinea
• Ghana
• the Democratic Republic of the Congo
• Kenya
• South Africa
• Uganda
• Zimbabwe

A 2005 outbreak in Angola killed more than 300 people.

However, in the rest of the world, only two people have died from the Marburg virus in the past 40 years - one person in Europe and one in the US.

Both had been on expeditions to caves in Uganda.

Health experts say the outbreak in Rwanda was confirmed in late September 2024.

This is the first time the virus has been found in Rwanda and the source has not yet been found.

Rwanda's neighbours Uganda and Tanzania reported Marburg outbreaks in 2017 and 2023, respectively.

Around 300 people in Rwanda who are known to have been in contact with confirmed cases are being monitored.

Some of those who have tested positive for the disease are healthcare workers.

The WHO is sending experts, testing kits and personal protective equipment to support Rwanda's efforts to tackle the outbreak.

The virus begins abruptly with:

• a fever
• severe headache
• muscle pains

This is often followed, three days later, by:

• watery diarrhoea
• stomach pain
• nausea
• vomiting

According to the WHO, "the appearance of patients at this phase has been described as showing 'ghost-like' drawn features, deep-set eyes, expressionless faces and extreme lethargy."

Many people go on to bleed from various parts of the body, and some die eight to nine days after first falling ill, because of extreme loss of blood and shock.

African green monkeys and pigs can carry it.

The Egyptian rousette fruit bat often also harbours the virus.

Among humans, it spreads through bodily fluids and contact with contaminated bedding.

Even after people have recovered, their blood or semen can remain infectious for many months afterwards.

There are no specific treatments or a vaccine for the virus, although trials are happening.

But a range of blood products, drug and immune therapies are being developed, the WHO says.

Doctors may be able to alleviate the symptoms by giving hospital patients plenty of fluids and using transfusions to replace lost blood.

People in Africa should avoid eating or handling bushmeat, according to Gavi, an international health organisation.

People should also avoid contact with pigs in areas with an outbreak, says the WHO.

Men who have had the virus should use condoms for a year after the onset of symptoms or until their semen tests negative for the virus twice.

Those who bury people who have died from the virus should also avoid touching the body.