CDC Statement on Marburg Cases in Rwanda – Updates & Response

The CDC first reported on the outbreak on September 30, 2024, following a notification from the Rwandan Ministry of Health. The agency has a long-standing collaborative relationship with Rwanda, dating back to 2002, and is deploying experts to assist with outbreak investigation and response.

Understanding Marburg Virus Disease

Marburg virus disease (MVD) is a highly lethal viral hemorrhagic fever, closely related to Ebola. It’s caused by the Marburg virus, which is naturally carried by certain species of bats. Transmission to humans occurs through contact with infected bats or, more commonly, through human-to-human transmission via direct contact with bodily fluids – blood, urine, saliva, sweat, feces, vomit, and even semen – of infected individuals. Healthcare workers are at particularly high risk due to potential exposure during patient care.

Symptoms of MVD typically appear abruptly, within 2-21 days of exposure, and can include fever, severe headache, muscle aches, vomiting, diarrhea, and eventually, severe bleeding. The case fatality rate, meaning the proportion of infected individuals who die from the disease, is alarmingly high, averaging around 23% as seen in the recent Rwandan outbreak, according to the World Health Organization (WHO). However, early supportive care, including fluid management and correction of blood clotting issues, has been linked to improved survival rates.

The Rwandan Outbreak: A Closer Seem

The outbreak in Rwanda was officially declared on September 27, 2024. As of December 19, 2024, the WHO reported 66 confirmed cases, 15 deaths, and 51 recoveries. The outbreak was declared over on December 20, 2024, after two consecutive 42-day periods (twice the virus’s incubation period) passed without any new confirmed cases. However, the WHO emphasizes that the risk of re-emergence remains, due to the potential for the virus to persist in the bodily fluids of recovered patients, particularly semen, and the presence of an animal reservoir within the country.

A significant proportion of the cases in Rwanda – almost 78% – have been among healthcare workers from two health facilities in Kigali, highlighting the occupational risk associated with MVD. Most cases were concentrated in three districts of Kigali city: Gasabo, Kicukiro, and Nyarugenge. The majority of confirmed cases (68%) were male, and nearly half (46%) were adults between the ages of 30 and 39.

CDC’s Response and U.S. Risk Assessment

The CDC’s response to the outbreak includes deploying subject matter experts to Rwanda to provide assistance with epidemiology, contact tracing, laboratory testing, and infection prevention and control in healthcare settings. The agency is leveraging its existing infrastructure and partnerships in Rwanda, including the Field Epidemiology Training Program (FETP), to strengthen the country’s capacity to respond to outbreaks. The CDC as well collaborates with the Rwandan government on initiatives related to HIV/AIDS and malaria, which have bolstered core public health capabilities.

Currently, the CDC assesses the risk to the general public in the United States as low. No cases of MVD related to this outbreak have been reported in the U.S. However, the CDC is maintaining vigilance and providing guidance to healthcare providers on recognizing and managing potential cases. The CDC website provides detailed information on Marburg virus disease, including symptoms, transmission, and prevention measures.

What to Expect in the Coming Weeks

While the outbreak in Rwanda has been declared over, ongoing surveillance and monitoring are crucial to detect any potential re-emergence of the virus. The WHO recommends maintaining early case detection and care capacities, sustaining the ability to respond quickly, and continuing risk communication and community engagement efforts. The CDC will continue to monitor the situation closely and provide updates as needed. Further research is also needed to better understand the animal reservoir of the Marburg virus and develop effective vaccines and treatments.