Disease Outbreak News
Marburg Virus Disease – Rwanda
Overview of the Situation
On September 27, 2024, the Ministry of Health in Rwanda announced the confirmation of cases of Marburg virus disease (MVD). Blood samples taken from individuals exhibiting symptoms were analyzed using real-time reverse transcription polymerase chain reaction (RT-PCR) at the National Reference Laboratory of the Rwanda Biomedical Center, yielding positive results for the Marburg virus. By September 29, 2024, there had been a total of 26 confirmed cases, with eight fatalities reported. These cases emerged from seven out of the country’s 30 districts. Notably, over 70% of the confirmed cases were healthcare workers from two medical facilities in Kigali. Currently, the affected patients are receiving care in hospitals. A contact tracing initiative is in progress, monitoring around 300 contacts of confirmed cases. This marks the first documented instance of MVD in Rwanda. The government is spearheading the response efforts with assistance from the World Health Organization (WHO) and other partners. At present, there is no established treatment or vaccine for MVD, emphasizing the importance of early medical intervention for individuals showing Marburg-like symptoms, which can enhance survival rates. The WHO has assessed the risk of this outbreak as very high nationally, high regionally, and low globally.
Situation Description
The announcement regarding the confirmed cases of MVD was made on September 27, 2024, following tests conducted on patients in health facilities across Rwanda. Blood samples from suspected cases were tested on September 26, 2024, and found positive for the Marburg virus. Additional samples are being sent to a regional reference laboratory for further confirmation.
As of September 29, 2024, the confirmed cases stood at 26, with a case fatality rate (CFR) of 31%, as eight out of the 26 patients succumbed to the disease. The cases have been identified in the following districts: Gasabo, Gatsibo, Kamonyi, Kicukiro, Nyagatare, Nyarugenge, and Rubavu. A significant proportion (over 70%) of the confirmed cases involve healthcare workers from two facilities in Kigali. All patients are currently receiving treatment in hospitals.
Contact tracing efforts are active, and approximately 300 contacts are under surveillance as of September 29, 2024. Notably, one individual who had contact with confirmed cases traveled to Belgium. Public health authorities in Belgium were notified of this contact and reported that the individual remained healthy throughout their monitoring period of 21 days, showing no symptoms and posing no risk to public health.
The source of this infection is still under investigation, and further information will be released as it becomes available. This situation represents the inaugural report of MVD in Rwanda.
Epidemiology
Marburg virus disease is characterized by its high virulence and the potential to cause hemorrhagic fever, sharing clinical similarities with Ebola virus disease. Both Marburg and Ebola viruses belong to the Filoviridae family (filovirus). Initial infection with the Marburg virus typically occurs through close contact with Rousettus bats, a species of fruit bat that can harbor the virus, often found in caves or mines.
Transmission of the Marburg virus occurs through direct contact with infected individuals’ blood, secretions, organs, or other bodily fluids, as well as contact with contaminated surfaces and materials (such as clothing and bedding). Healthcare workers are particularly at risk when treating patients with suspected or confirmed MVD. Traditional burial practices involving direct contact with the deceased’s body can also contribute to the spread of the Marburg virus.
The incubation period for MVD can range from 2 to 21 days. The onset of illness is usually abrupt, marked by high fever, severe headache, and extreme malaise. Symptoms such as severe watery diarrhea, abdominal pain, cramping, nausea, and vomiting may appear around the third day. While not all cases present with hemorrhagic signs, severe hemorrhagic manifestations can develop between days five and seven post-symptom onset. Fatal cases typically exhibit some form of bleeding, often from multiple sites, with death most frequently occurring between eight and nine days after symptoms appear, commonly preceded by significant blood loss and shock. Currently, there are no approved treatments or vaccines for MVD, though several candidate vaccines are under development.
Historically, multiple outbreaks of MVD have been documented in countries neighboring Rwanda, such as the Democratic Republic of the Congo, Uganda, and the United Republic of Tanzania. The latest outbreaks were reported in Equatorial Guinea and the United Republic of Tanzania from February to June 2023, with the affected region in Tanzania bordering Rwanda. Other countries in the African Region that have experienced MVD outbreaks include Angola, Ghana, Guinea, Kenya, and South Africa.
Public Health Response
The Government of Rwanda is leading the response efforts in collaboration with WHO and other partners. To facilitate early detection of cases, the Ministry of Health has shared a hotline number from the Rwanda Biomedical Center with the public for reporting symptoms.
Ongoing efforts include detailed epidemiological investigations, contact tracing, and the isolation of suspected cases for testing and treatment. Infection prevention and control (IPC) measures and Water, Sanitation, and Hygiene (WASH) protocols are being enforced in all health facilities. Additionally, risk communication and community engagement strategies (RCCE) are being enhanced to inform and mobilize communities, addressing rumors and misinformation effectively.
Following the initial confirmation of MVD in the country, WHO is assisting with the transportation of samples to a regional reference laboratory for further testing. The organization is also focused on delivering supplies, including laboratory testing kits and personal protective equipment. WHO and its partners are working closely with the government to facilitate access to available candidate MVD vaccines and therapeutics for potential clinical trials. The Ministry of Health has designated two experienced principal investigators to oversee these trials.
Moreover, WHO is collaborating with neighboring countries, including the Democratic Republic of Congo, Burundi, Kenya, Tanzania, and Uganda, to evaluate their operational readiness to respond to the Marburg outbreak. An assessment of the risk for South Sudan is also underway, considering trade routes between countries. The readiness of unaffected districts in Rwanda is being ensured to prevent the spread of the virus and to swiftly identify any spillover incidents.
WHO Risk Assessment
Marburg virus disease (MVD) is classified as an epidemic-prone disease associated with a high case fatality rate (CFR) ranging from 24% to 88%. Clinically diagnosing MVD can be challenging in its early stages, as symptoms may resemble those of other infectious diseases, such as malaria, typhoid fever, shigellosis, meningitis, and other viral hemorrhagic fevers. Epidemiological features, including exposure history to bats, caves, or mining, can aid in distinguishing MVD from other viral hemorrhagic fevers, while laboratory testing remains crucial for confirming diagnoses.
The notification of 26 confirmed cases, particularly with over 70% of those being healthcare workers from different health facilities, raises significant concern. Nosocomial infections could lead to further transmission if not managed swiftly. Thus, the importance of screening all individuals entering health facilities and maintaining inpatient surveillance for timely identification, isolation, and notification is paramount. Additionally, the need for identifying and monitoring all probable and confirmed cases is vital. The source of the outbreak, its geographical extent, the likely onset date, and other epidemiological details regarding the cases are still pending further investigation.
There exists a risk of the outbreak spreading to neighboring countries, especially since the reported cases are located near borders with the Democratic Republic of the Congo, the United Republic of Tanzania, and Uganda. The potential for international spread is also heightened, as confirmed cases have been identified in the capital city, which has an international airport and road connections to various East African cities. A contact has been confirmed to have traveled internationally to Belgium, and appropriate measures have been instituted in response. Providing optimized supportive care for patients, which includes careful monitoring, intravenous fluid administration, and early management of complications, can enhance patient survival rates. Promising vaccines and therapeutic candidates for MVD are in development, but they require validation through clinical trials. WHO has provided guidance to the Ministry of Health on effective case management strategies.
According to WHO’s assessment, the risk of this outbreak is classified as very high at the national level, high at the regional level, and low globally. Investigations to ascertain the complete extent of the outbreak are ongoing, and this risk assessment will be revised as new information becomes available.
WHO Recommendations
Control of the MVD outbreak necessitates a multifaceted approach, incorporating prompt isolation and management of cases, rigorous surveillance, active case search, and contact tracing. Optimal laboratory services, infection prevention and control protocols, and social mobilization strategies are essential for effective outbreak containment. Raising awareness within communities about the risk factors associated with Marburg virus infection and educating individuals on protective measures can significantly mitigate human transmission. WHO advises the following risk reduction strategies to effectively diminish MVD transmission within healthcare facilities and communities:
To minimize infections and fatalities, it is critical to enhance community awareness regarding the risk factors associated with Marburg virus infection and the protective measures that individuals can adopt to limit their exposure to the virus. Individuals exhibiting symptoms should be encouraged to seek immediate medical attention at health facilities or designated treatment centers to reduce the risk of community transmission and improve their chances of recovery.
Strengthening surveillance initiatives, including the widespread dissemination of MVD case detection protocols, should be prioritized in all affected regions, incorporating contact tracing and active case identification.
Infection prevention and control measures within health facilities must be reinforced or established. This includes creating systems for screening, referral, and isolation of suspected MVD cases. Health facilities should implement active screening protocols for all individuals entering the facility in accordance with the suspect MVD case definitions, ensuring the prompt isolation of both suspected and confirmed cases.
Health facilities must ensure
adequate availability of personal protective equipment (PPE) for health workers. The WHO recommends that staff receive training on the appropriate use of PPE, alongside essential IPC practices, to safeguard their health.
Surveillance should be extended to monitor events involving bats and other wildlife, as these can serve as reservoirs for zoonotic diseases. Understanding and addressing risks associated with contact with wild animals are critical in controlling the outbreak.
Regularly updating WHO and other partners on the situation is crucial for supporting an efficient response, resource allocation, and ongoing risk assessment.
