The Marburg virus outbreak in Rwanda raises concerns about the possibility of spread

A large outbreak of Marburg virus in Rwanda is sparking international concern about the possibility of spread beyond the country's borders.

The 27 cases identified so far make the outbreak one of the largest in Marburg since records began. Nine of these people have died. There are currently no approved vaccines to combat the disease.

Most of the cases detected so far – over 70% – have been among medical professionals working in two hospitals in the capital Kigali, home to 1.7 million people. Kigali is also a regional and international travel hub; Flights from the city connect to destinations in approximately 20 countries in Africa, the Middle East and Asia.

In a statement late Monday, the World Health Organization rated the risk of spread to neighboring countries as high. It was also noted that there is a risk of spread beyond East Africa.

In fact, a contact of a suspected case – the person currently believed to be the first case or index case in this outbreak – traveled to another country, the WHO said. The statement did not name the country, but in a statement posted on the social media site, sources told STAT that Belgian authorities had been informed of the possibility that the person may have been in contact with a case. The WHO statement said the country in question had “implemented appropriate response measures.”

“WHO assesses the risk of this outbreak as very high at the national level, high at the regional level and low at the global level,” the WHO said. “Investigations are ongoing to determine the full extent of the outbreak and this risk assessment will be updated as further information becomes available.”

Although the disease causes a similar illness to its cousin virus Ebola, there have been fewer than ten cases of outbreaks in Marburg in the past. Only two outbreaks involving more than 100 cases have been reported. The largest Marburg outbreak to date occurred in Uije, Angola, in 2004–2005, where there were 252 confirmed cases and 227 deaths.

Experts believe Rwanda's advanced health system is up to the challenge of dealing with this outbreak.

“Rwanda has become a standout in the region because of its contribution to health security and its significantly improved response not only to things like that – outbreaks and preparedness – but also to really chronic diseases and a lot of other things that have kind of plagued the region “developed in recent history,” said Craig Spencer, an associate professor at Brown University’s School of Public Health.

Spencer, who has worked with Doctors Without Borders (or Médecins Sans Frontières in French) on a number of Ebola outbreaks – and was infected with Ebola in the West Africa outbreak in 2014 – has carried out relief efforts in Rwanda, although not recently. The country has expanded its capacity to the point where it typically no longer needs the kind of outside help that Médecins Sans Frontières provides, Spencer said, adding: “Their health system has become remarkably much stronger.”

It is not clear how long the outbreak has been going on or in which part of the country it began. Cases have been identified in seven of the country's 30 districts. The Rwandan government is conducting contact tracing to identify people who have been exposed to confirmed cases and may have been infected. So far, 300 contacts are being monitored.

In many places hit by outbreaks of viral hemorrhagic fever – Ebola and Marburg fall into this disease category – cases occurring among health care workers may indicate an outbreak that has been simmering in the community for some time and only then becomes apparent will when healthcare workers begin to become infected. This is particularly the case when an outbreak begins in a remote area with poor road access to other locations.

But Spencer said the quality of Rwandan health care and the quality of the country's road network may mean that is not the case here. It was possible, he said, that early patients were treated in Kigali.

While the idea of ​​Marburg or Ebola cases in a major city is often a cause for concern – the outbreak in West Africa erupted as Ebola swept through urban centers – the situation in this case may be less problematic because of the response capacity in place in Kigali, said he.

The WHO has reportedly sent a team of seven experts to Rwanda to help with the response. The Centers for Disease Control and Prevention, which has had an office in Rwanda for more than 20 years, has also offered help.

The outbreak comes at a time when several of Rwanda's neighboring countries are struggling with Mpox outbreaks. Spencer, who has also worked in Burundi and the Democratic Republic of Congo, said if the virus spreads in those countries, controlling this outbreak would become significantly more difficult.

There are several experimental drugs and vaccines for Marburg, but none have been approved yet. The relative rarity of the Marburg outbreaks and their small size have previously made it impossible to test these products in the field.

While the two approved Ebola vaccines were sponsored by pharmaceutical giants Merck and Janssen (a division of Johnson & Johnson), the Marburg vaccines in development are in the hands of nonprofits, IAVI and the Sabin Institute.

Rwanda would have to agree to allow vaccines or medicines to be tested in this outbreak. But even if that were the case, IAVI President and CEO Mark Feinburg said the company currently does not have any doses of its vaccine to test. STAT has asked the Sabin Institute if it has doses that could be tested but has not yet received a response.

This article has been updated with a revised case count from the Rwandan Ministry of Health.