How Rwanda is containing a deadly Marburg virus outbreak

Rwanda is battling its first outbreak of Marburg virus disease, a deadly disease linked to Ebola. There are no approved vaccines or treatments for the disease. According to the Rwandan Ministry of Health, as of October 6, the outbreak had infected 56 people and killed 12 of them. With support from the Africa Centers for Disease Control and Prevention (Africa CDC) and other partners, the Rwandan government is implementing rigorous testing, contact tracing and quarantine measures to contain the outbreak. A clinical trial of a vaccine candidate from the Sabin Vaccine Institute will begin soon after about 700 doses were delivered following a request from the Rwandan government. However, challenges remain, including the similarity of the disease's symptoms to those of malaria, the need for faster diagnostic tools, and the fact that the majority of known infected people are healthcare workers.

The Rwandan government, Africa CDC and others are working to contain the outbreak and are currently tracing the contacts of approximately 400 people who may have been exposed to the virus. Cases have been identified in eight of the country's 30 counties, with healthcare workers accounting for a staggering 80 percent of those confirmed infected. Concerns about possible international spread were heightened when Germany announced that a medical student who had traveled to Rwanda and his partner had been in contact with a confirmed case, but both later tested negative.

“Marburg virus is known to be associated with a very high mortality rate, if not the second deadliest virus known to date in terms of affecting the human body and destroying the immune response, leading to mortality,” says Rwandas Minister of Health Sabin Nsanzimana. He describes the high proportion of cases among health workers as an unfortunate reality. “They are the first to be affected by such diseases because they deal with sick people from different places and backgrounds,” says Nsanzimana.

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Jean Kaseya, Director General of Africa CDC, emphasizes the need to support Rwanda by decentralizing testing capacity and ensuring adequate supplies. “We need to prevent widespread community transmission,” where a disease spreads among people who have no known contact with other infected people. “The government is doing its best with testing and our job is to ensure that Rwanda does not lack supplies,” Kaseya added. “Since there is no rapid test yet, we are working on decentralizing PCR (polymerase chain reaction) tests so that all regions can react quickly.” (These PCR tests are high-precision molecular tests for the virus.)

Nsanzimana, who is committed to containing the Marburg outbreak, spoke with us Scientific American about the current status and containment measures in Rwanda.

(An edited transcript of the interviews follows.)

What steps is Rwanda taking to prevent the international spread of the Marburg virus, especially when possible cases appear in distant countries such as Germany?

We have implemented several strategies to prevent the spread of the virus beyond our borders. Key to this is expanding our contact tracing and quarantine efforts. We test individuals regularly and have intensified checks at both entry and exit points. The more contacts you explore, the better, as you exhaust all possibilities of the virus or outbreak spreading.

We have issued a travel notice to further enforce these protocols. This will ensure that no potential cases travel abroad, such as the current case of a student who had contact with a confirmed case. The student tested negative before leaving Rwanda and again upon arrival in Germany. This collaboration within the framework of international health regulations shows the effectiveness of our measures. We are also focusing on strengthening exit controls, particularly for those in the incubation phase of the virus, to minimize the risk of transmission. We will stop this outbreak before it affects other places in the country, region or even beyond.

What challenges did you face in containing the outbreak?

The initial challenge in identifying the Marburg cases was the similarity of their symptoms to those of malaria, a common disease in the region. Symptoms of both diseases include high fever, severe headaches, muscle pain, joint pain and fatigue – and later also gastrointestinal complaints, nausea and vomiting, which are very common with malaria.

How big is the outbreak currently and how is Rwanda dealing with it?

At the moment we are primarily pursuing a significant group of cases. This cluster is focused on a single hospital department, specifically the intensive care unit (ICU) where the original patient was treated. Unfortunately, several doctors and nurses became infected while performing resuscitation and other critical procedures. We have identified approximately 400 contacts and are following them carefully to ensure we do not miss any potential cases.

Cases have remained largely confined to this ICU cluster, and we have not observed widespread spread beyond that. To further reduce the risk, we have increased community surveillance and are investigating anyone who has symptoms similar to Marburg virus, such as: B. high fever, headache and muscle pain. Given the overlap of these symptoms with malaria, our screening efforts are cautious but comprehensive so as not to miss a single case.

What resources does Rwanda need to effectively control the outbreak and how quickly can you detect cases?

Our primary testing method is polymerase chain reaction (PCR), which provides results within eight to ten hours. This turnaround time has been instrumental in quickly identifying cases, particularly given the urgent need to contain the outbreak. However, as we collect more samples from community surveillance, our laboratories are becoming more and more overwhelmed.

To improve our response, we need rapid diagnostic tools that would ease the burden on our PCR testing facilities. We are also currently working on further expanding our PCR capabilities. We are in the process of decentralizing testing to ensure more regions have the capacity to test and respond quickly.

Regarding genomic epidemiology, we have built our genomic sequencing infrastructure. This will help us track the virus more effectively. Although we already have a solid foundation, our teams are currently prioritizing case identification to ensure we capture every positive case. As we make progress, we will begin sharing genomic data that will provide deeper insights into the outbreak.

Rwanda already has a strong genome sequencing infrastructure. Why haven't we seen faster genomic analysis during this outbreak?

While we have indeed developed significant genome sequencing capabilities, our priority has been to rapidly screen and identify positive cases. Our teams are working around the clock to ensure no case is missed, but we are now starting to analyze and generate genomic data. As we continue to gain a clearer picture of the genetic makeup of the virus, we will share more information with our partners and the public.

Is the outbreak currently under control?

The outbreak is under control but not yet fully contained. We are making progress daily and remain vigilant in our efforts to review and monitor all potential cases. Our top priority is to ensure the virus does not spread beyond the current cluster. We are confident that with continued testing, quarantine efforts and community surveillance we can keep the situation under control.

There are no approved vaccines available. However, can you share information about a possible vaccine clinical trial?

We chose a vaccination protocol for this trial that allows us to keep pace with the times – a quick, rapid protocol that also meets all the requirements.