A significant outbreak of the Marburg virus in Rwanda is raising international alarm regarding the potential for transmission beyond the nation's borders.
With 27 confirmed cases to date, this outbreak ranks among the largest recorded instances of Marburg virus. Tragically, eight of those affected have succumbed to the illness. Currently, there are no approved vaccines available to address this disease. The majority of the reported cases—over 70%—involve healthcare workers at two hospitals in Kigali, the capital city with a population of 1.7 million. Kigali is a key regional and international travel hub, with flights connecting to approximately 20 countries across Africa, the Middle East, and Asia. In a statement released late Monday, the World Health Organization assessed the risk of the virus spreading to neighboring nations as high, indicating a potential for further dissemination beyond East Africa. Notably, one individual linked to a suspected case—identified as the index case in this outbreak—traveled to another country, according to the WHO. While the specific country was not disclosed in the statement, a slide shared on the social media platform X indicated Belgium. Sources informed STAT that Belgian authorities have been alerted to the possibility of contact with a confirmed case. The WHO's statement confirmed that "appropriate response measures have been implemented" by the relevant country.The World Health Organization (WHO) has evaluated the outbreak's risk as very high at the national level, high at the regional level, and low at the global level. Ongoing investigations aim to ascertain the full scope of the outbreak, and the risk assessment will be revised as new information becomes available.
While the disease presents symptoms akin to those caused by the Ebola virus, historical data indicates that Marburg outbreaks have typically involved fewer than 10 cases. Only two outbreaks have been documented with over 100 cases, the largest being in Uije, Angola, during 2004-2005, which resulted in 252 confirmed cases and 227 fatalities.
Experts believe that Rwanda's robust healthcare system is well-equipped to manage this outbreak effectively.
“Rwanda has emerged as a leading example in the region for its contributions to health security, demonstrating significant improvements in its response capabilities not only to outbreaks and preparedness but also to chronic diseases and various other health challenges that have affected the region in recent years,” stated Craig Spencer, an associate professor at Brown University’s School of Public Health.
Spencer, who has collaborated with Doctors Without Borders on several Ebola outbreaks and contracted the virus during the West African outbreak in 2014, has previously engaged in response efforts in Rwanda. He noted that the country has enhanced its healthcare capabilities to the extent that it generally does not require the type of external assistance that MSF offers, remarking, “Their health system has become remarkably much stronger.”
The duration of the outbreak and its initial location within the country remain uncertain. So far, cases have been identified in seven out of the 30 districts. The Rwandan government is actively engaged in contact tracing to locate individuals who may have been exposed to confirmed cases and could potentially be infected. Currently, 300 contacts are under surveillance.
In regions experiencing viral hemorrhagic fever outbreaks, such as Ebola and Marburg, the emergence of cases among healthcare workers often indicates that the outbreak has been ongoing within the community, only becoming evident when health professionals start to contract the disease. This is especially true in remote areas with limited access to transportation.
However, Spencer noted that the high standard of healthcare in Rwanda and the quality of its road infrastructure may suggest a different scenario. He proposed that initial patients might have sought treatment in Kigali.
Additionally, while the prospect of Marburg or Ebola cases in a major city typically raises concerns—similar to the West African outbreak that escalated when Ebola reached urban areas—this situation may be less alarming due to the robust response capabilities present in Kigali, according to Spencer.
The World Health Organization has dispatched a team of seven experts to assist with the response efforts. The Centers for Disease Control and Prevention, which has had a presence in Rwanda for over two decades, has also extended its support.
This outbreak coincides with ongoing mpox outbreaks in several neighboring countries. Spencer, who has experience in Burundi and the Democratic Republic of the Congo, warned that if the virus spreads to these nations, managing the outbreak would become significantly more difficult.
Several experimental drugs and vaccines for Marburg are currently under development, but none have received official approval to date. The rarity and limited scale of Marburg outbreaks have hindered the ability to conduct field tests for these products.
In contrast to the two licensed Ebola vaccines, which were developed by major pharmaceutical companies Merck and Janssen (a subsidiary of Johnson & Johnson), the Marburg vaccines in progress are being developed by nonprofit organizations, specifically IAVI and the Sabin Institute.
For testing to occur during this outbreak, Rwanda would need to consent to the use of these vaccines or drugs. However, even with such consent, Mark Feinberg, the president and CEO of IAVI, indicated that they currently lack available doses of their vaccine for testing purposes. STAT has reached out to the Sabin Institute regarding the availability of doses for testing but has yet to receive a reply.