Marburg virus disease – Equatorial Guinea and the United Republic of Tanzania

Equatorial Guinea and the United Republic of Tanzania have been responding to separate outbreaks of Marburg virus disease (MVD) since early February and late March 2023, respectively.

In Equatorial Guinea, from 13 February to 1 May 2023, 17 laboratory-confirmed MVD cases and 23 probable cases have been reported. The last confirmed case was reported on 20 April. Among the laboratory-confirmed cases, there are 12 deaths (Case Fatality Ratio (CFR) 75%).For one confirmed case, the outcome is unknown. Among the confirmed cases, four have recovered. All of the probable cases are dead. The most affected district is Bata in Litoral province, with 11 laboratory-confirmed MVD cases reported.

In the United Republic of Tanzania, between 16 March to 30 April 2023, a cumulative total of nine cases including eight laboratory-confirmed cases and one probable case have been reported. The last confirmed case was reported on 11 April 2023. A total of six deaths (CFR 66.7%) have been reported, including one probable case and five among the confirmed cases. Among the confirmed cases, three have recovered. All cases have been reported from Bukoba district, Kagera region.

Health authorities in both countries have shown strong political commitment. In recent weeks they have further strengthened critical response functions, such as disease surveillance, including at points of entry; laboratory activities; clinical case management; infection prevention and control; risk communication and community engagement; and operations support and logistics with support of WHO and partners.

WHO continues to monitor the situation in these two countries closely and to support the responses.

Description of the situation

Equatorial Guinea:

Since the declaration of the outbreak on 13 February 2023, a total of 17 laboratory-confirmed cases of MVD and 23 probable cases have been reported as of 1 May (Figure 1). Among laboratory-confirmed cases, 12 deaths were recorded (CFR 75%). For one confirmed case, the outcome of the illness is unknown. All probable cases are dead. Five districts (Bata, Ebebiyin, Evinayong, Nsok Nsomo and Nsork) in four of the country’s eight provinces (Centro Sur, Kié-Ntem, Litoral and Wele-Nzas) have reported confirmed or probable cases (Figure 2). The most affected district is Bata in Litoral province, with 11 laboratory-confirmed MVD cases reported.

Among the confirmed cases, four have recovered and five have been reported among healthcare workers, of whom two died.

Among the reported cases, many are linked within a social network/gathering or by geographic proximity, however, the earlier presence of cases and/or clusters across multiple districts without clear epidemiologic links may indicate undetected virus transmission.

There are currently no confirmed cases in the Marburg treatment centre following the most recent discharge of a patient on 26 April 2023. This brings the total of survivors to four since the outbreak was declared.

Figure 1. MVD cases by week of symptom onset* and case classification, Equatorial Guinea, between 13 February to 1 May 2023.

Among MVD laboratory-confirmed cases with age and sex information (n = 16), the majority occurred among females (10/16; 62.5%), while the most affected age group is 40-49 years (6/16; 37.5%), followed by the age groups 30-39 years (3/16; 18.8%), 10-19 years (2/16; 12.5%), and 0-9 years (2/16; 12.5%).

In the last 21 days (from 11 April to 1 May 2023), two confirmed cases were reported from Bata district (Figure 3). These cases had a known epidemiological link to a confirmed case, through a family cluster or through a healthcare setting.

Figure 2. Map of Equatorial Guinea districts reporting confirmed and probable MVD cases or affected district reporting contacts with cases, between 13 February to 1 May 2023 .

Figure 3. Map of district reporting MVD confirmed cases in the last 21 days (11 April  – 1 May 2023), Equatorial Guinea.

Since the declaration of the MVD outbreak on 21 March 2023, a total of nine cases (eight laboratory-confirmed and one probable case) have been reported as of 30 April 2023 (Figure 4). Among the total cases, six deaths were recorded (CFR 66.7%). Among the confirmed cases, three have recovered, and two have been reported among healthcare workers, one of whom died .

In the last 21 days, from 10 to 30 April, one confirmed case was reported on 11 April.  This case was the mother of a previously reported MVD case, a child of 18 months old, who died on the same day. The mother was quarantined as soon as MVD was detected in the child in March. No further contacts linked to this case have been reported. There are currently no confirmed cases in the treatment centre in Bukoba following the discharge of the confirmed patient on 21 April 2023. This brings the total of survivors to three since the outbreak was declared.

Figure 4: Distribution of MVD cases (confirmed and probable) by date of symptom onset in the United Republic of Tanzania, as of 30 April 2023.

All cases are reported from Bukoba district in Kagera Region.

Cases ranged in age  from 1 to 59 years old (median 35-year-old), with males being the most affected (n= 6; 66.7%).

Epidemiology of Marburg virus disease

Marburg virus spreads between people via direct contact through broken skin or mucous membranes with the blood, secretions, organs, or other bodily fluids of infected people and with surfaces and materials such as bedding, and clothing contaminated with these fluids. Healthcare workers have previously been infected while treating patients with suspected or confirmed MVD. Burial ceremonies involving direct contact with the deceased’s body can also contribute to the transmission of the Marburg virus.

The incubation period varies from 2 to 21 days. Illness caused by the Marburg virus begins abruptly, with high fever, severe headache, and severe malaise. Severe haemorrhagic manifestations may appear between five and seven days from symptom onset. However, not all cases have haemorrhagic signs, and fatal cases usually have some form of bleeding, often from multiple areas.

Although no vaccines or antiviral treatments are approved to prevent or treat the virus, Remdesivir is being used on a modified, monitored emergency-use basis in Equatorial Guinea. Early supportive care – rehydration with oral or intravenous fluids – and treatment of specific symptoms and co-infections can improve survival. A range of potential treatments are being evaluated, including blood products, immune therapies, and drug therapies.

This is the first reported outbreak of MVD in both Equatorial Guinea and the United Republic of Tanzania. Other MVD outbreaks have been previously reported in Ghana (2022), Guinea (2021), Uganda (2017, 2014, 2012, 2007), Angola (2004-2005), the Democratic Republic of the Congo (2000 and1998), Kenya (1990, 1987, 1980) and South Africa (1975).

In Equatorial Guinea:

• The Government activated a regional public health emergency operation center in Bata under the leadership of the Minister of Health and the Minister Delegate.

• The MoH developed a national operational response plan and is currently organising regular meetings to coordinate response activities at the national, regional, and district levels.

• Partners from the Global Outbreak Alert and Response Network (GOARN) were mobilized to assist response activities. Several experts have been deployed through WHO to support case management, laboratory, epidemiology, and surveillance functions.

• The UN system, including WHO, continues to advocate for the Prevention of Sexual Exploitation and Abuse as it awaits government agreement to undertake community-based activities.

• Several partners are supporting the government-led response through the provision of technical, financial and operational support. These include WHO, the US Centers for Disease Control and Prevention (US-CDC), the Cuban Medical Brigade, the Africa Centre for Disease Control and Prevention (Africa CDC), the International Federation of the Red Cross and Red Crescent Societies (IFRC), and the United Nations Children’s Fund (UNICEF).

• The alert and dispatch center for MVD alert management across the region developed by the MoH, with support from WHO, is operational. However, the daily level of alerts reported remains low.

• WHO is supporting the MoH in training and supportive supervision of surveillance activities, including case investigation and contact tracing and coordinating with healthcare facilities for active surveillance.

• WHO is coordinating with the US-CDC and the Cuban Medical Brigade on human resources and activity distribution.

Laboratory

• With the support of the US-CDC, and WHO, a laboratory with RT-PCR capacities is set up in Bata for MVD diagnostic and national staff continue to be trained.

• WHO is supporting the strengthening of sample collection and sample transportation system, to ensure quality and timely testing of samples.

• WHO continues to work with the MoH and support partner coordination efforts towards establishing  Marburg testing and sequencing capacity in Malabo.

• WHO continues to support the MoH in the operations of the Mondong Treatment Center in Bata. In addition to the 18 individual beds, two cubes¹  were installed for improved patient care and a well-stocked pharmacy was put in place.

• WHO continues to support MoH in the coordination of a referral system, including three ambulances that can retrieve suspected and confirmed patients from any district in the region and bring them to the Mondong treatment center.

• WHO is supporting the MoH in the establishment of a survivor clinic that provides medical and psychological care and testing to survivors.

• WHO provides continual training of local clinical and hygienist staff and provides clinical mentorship at the treatment centre.

• WHO continues to support the MoH regional task force for coordination of IPC activities and a national strategy for the IPC response.

• WHO continues to support the MoH in providing supervision and mentorship to complete evaluations and improvement plans at priority healthcare facilities and training of health workers.

• WHO continues to work with partners to advocate for improved Water, Sanitation and Hygiene (WASH) in health facilities, in particular water supply and waste management.

• WHO continues to support the decontamination of healthcare facilities, including  training of teams in priority hospitals.

• WHO has recruited and trained five national IPC focal points in Bata, Ebibeyin, Mongomo, Evinayong and Malabo.

• Safe and dignified burials teams have been established in Bata and Ebibeyin. Training of these teams on taking oral swabs of the deceased is on-going and needs to be scaled up.

• WHO is coordinating with other key partners to ensure timely, relevant and actionable RCCE messaging, and activities reach affected and at-risk populations. (UNICEF, IFRC, Africa CDC, among others).

• WHO is supporting public awareness and capacity building for RCCE national experts, social mobilisers and community leaders (such as civil society organizations, religious leaders, and women groups).

• Intensive public awareness and sensitization sessions have been conducted to sensitize decision makers in Malabo and affected communities  in Mongomo District.

• Community engagement with religious leaders, and with school delegates have been intensified.

• An RCCE national plan for (April-June 2023) has been developed with partners. Implementation is ongoing in all affected districts responding to the outbreak. Preparedness and readiness activities are ongoing in Malabo.

• Media networks in Bata have been engaged to understand and amplify protective messages to communities in the local languages, and in French and Spanish.

• WHO is supporting health authorities in convening key travel and transport partners to strengthen capacities and preventive measures at points of entry.

• On 26 April 2023, WHO organized a webinar with the support of the US-CDC and the International Organization for Migration (IOM) to raise awareness on the necessary border health readiness and response activities in the context of MVD outbreaks for affected and neighboring countries.

• WHO has provided operational and logistics support and maintenance of the Marburg treatment centre, including structural rehabilitation, provision of electricity and water, and supply chain management.

• WHO has established support for fleet management, including three ambulances on standby 24/7 at the Bata treatment centre, and approximately 20 vehicles. WHO has provided essential medicines and supplies to all pillars. Procurement is ongoing.

• WHO has established a central warehouse for essential items in Bata, which supports distribution to other areas.

• WHO developed a readiness checklist to assist neighbouring countries in assessing their level of readiness, and identifying potential gaps and concrete actions to be taken in case of any potential outbreak of filovirus including MVD. The checklist consists of several key components and an average score is calculated to provide readiness scores to each of the identified countries. A second round of readiness assessment across all pillars was conducted for Cameroon and Gabon. As of 3 May 2023, the sub-region’s overall readiness capacity was evaluated at 66%.

• Based on the gaps identified during the assessments, a gap analysis was conducted and shared with Cameroon and Gabon to inform priority readiness activities. The identified gaps would be addressed through the optimization of operational capacities and capabilities using various strategies, including trainings, table-top exercises, and simulation exercises. Additionally, the deployment of experts would be employed to support the implementation of the readiness activities.

In the United Republic of Tanzania:

• The Ministry of Health holds daily response meetings to discuss the ongoing response activities. These meetings are attended by heads of pillars and partners

• Resource mobilization activities by the Ministry of Health, in collaboration and support from WHO and UNICEF, are ongoing

• The MoH continue capacity building efforts for the regional response team .

• Prevention of sexual misconduct activities are ongoing at the country level. This include briefing of all Emergency Prepared and Response (EPR) new comers, signature and display of code of conduct at any WHO event, refresher for all WHO personnel, printing of awareness materials,  for both partners, and community.

• WHO also supports the Inter-agency protection of sexual exploitation, abuse, and harassment (PSEAH) network in   facilitating community awareness sessions and ensuring that the reporting mechanism is well known to all community members. In addition,  WHO ,in coordination with the Inter-agency PSEAH network conducted the PSEAH Rapid risk assessment along with  risk mitigation measures.

• Contact tracing activities ongoing: As of 30 April, a cumulative of 212 contacts have completed 21 days follow up.

• Active case search and alert management is ongoing. The daily level of alerts reported remains low. As of 30 April, a total of 176 alerts have been reported since the start of the outbreak.

• Capacity building activities are ongoing to train the regional laboratory officers on Marburg specimen management and analysis.

• No new hospitalizations have taken place since the last case was discharged on 21 April. However, suspect cases identified continue to be isolated and receive treatment while awaiting for MVD testing.

• Supervision and orientation on proper donning and doffing of personal protective equipment (PPE) is ongoing

• Activities include public awareness through radio, mass sensitization and information dissemination on MVD to Community Health Workers and community leaders in Bukoba district

• The MoH continues to provide information on MVD through social media platforms.

• Ongoing tracking of rumors and misinformation is being performed using established community-based platforms.

• Information Education and Communication material continues to be reviewed and disseminated, as well as off-line social listening findings (Africa Infodemic Response Alliance, Afya call center, community polling survey)

• Activities to enhance screening at points of entry (PoE) are ongoing, including for domestic travellers to identify any suspected or probable cases of MVD. As of 30 April, over 250 000 people have been screened.

• Relevant PoE have been assessed and capacities enhanced through the provision of health education materials, hand washing equipment, and medical supplies and infrastructure for screening and isolation.

• With support from WHO, medical supplies including thermo-scanners, spray pumps, surgical masks, face shields, burial bags, and other PPEs have been provided.

• Following a joint assessment with UNHCR, WHO is currently supporting a proposal of eight beds isolation unit for UN staff in the UNHCR compound in Kigoma region.

• First round of WHO readiness assessment was conducted for Burundi, the Democratic Republic of Congo, Kenya, Rwanda, and Uganda. As of 3 May 2023, the overall readiness capacity for this sub-region was evaluated at 70%.

• Based on the gaps identified during the assessments, a gap analysis was conducted and shared with the mentioned five countries to inform priority readiness activities. The identified gaps would be addressed through the optimization of operational capacities and capabilities using various strategies, including trainings, table-top exercises, and simulation exercises. Additionally, the deployment of experts would be employed to support the implementation of the readiness activities.

Both countries have reported MVD outbreaks for the first time.

In Equatorial Guinea, while many cases are linked within a social network/gatherings or by geographic proximity, the earlier presence of cases and/or clusters across multiple districts without clear epidemiologic links may indicate undetected virus transmission. The last cases occurred in Bata, the most populated city and economic hub of Equatorial Guinea, with an airport and seaport, posing challenges for the response. The country surveillance system remains suboptimal, with few alerts reported. Additionally, there are population movements between the different districts of the mainland and island regions. Frequent population movements and porous land borders are also reported in the districts bordering Cameroon and Gabon, with suboptimal surveillance at land entry points and countless uncontrolled paths or trails along the border with Cameroon and Gabon.

In the United Republic of Tanzania, the affected region, Kagera, borders three countries (Uganda to the north, and Rwanda and Burundi to the west) and Lake Victoria, and cross-border population movements may increase the risk of disease spread. Following the recent Ebola virus outbreaks in the Democratic Republic of the Congo from 23 April – 3 July 2022 and from 21 August – 27 September 2022, and Sudan ebolavirus outbreak in Uganda from 20 September 2022 to 11 January 2023, neighbouring countries in the subregion, including the United Republic of Tanzania, have been building preparedness capacities against filovirus diseases.  However, an epidemiological investigation, which is still being carried out,  has not revealed the source of the outbreak  which may pose an additional risk to the population in the affected district.

In March 2023, WHO assessed the public health risk posed by the MVD outbreaks in Equatorial Guinea and the United Republic of Tanzania as very high at the national level, high at the sub-regional level, moderate at the regional level, and low at the global level.  WHO continues to monitor the situation in these two countries closely.

MVD outbreak control relies on using a range of interventions, such as early isolation and optimized supportive care; surveillance including active case search, case investigation and contact tracing; an optimal laboratory service; infection prevention and control; safe and dignified burial; and social mobilization. Risk Communication and Community engagement is key to successfully controlling MVD outbreaks. Raising awareness of risk factors for infection with Marburg virus and the protective measures that individuals can take is an effective way to reduce human transmission.

Health workers caring for patients with confirmed or suspected MVD should apply IPC measures including, standard and transmission-based precautions and wearing personal protective equipment and performing hand hygiene to avoid contact with the patient’s blood and body fluids and with contaminated surfaces and objects. Health facilities should ensure environmental controls, such as adequate water, sanitation and hygiene, as well as that safe infectious waste management protocols are in place to enable health workers to practice IPC measures. In addition, healthcare facilities should conduct appropriate screening, isolation and referral of suspected cases. WHO recommends that male survivors of MVD practice safer sex for 12 months from onset of symptoms, or until their semen twice tests negative for the Marburg virus. WHO does not recommend isolation of male or female convalescent patients whose blood has tested negative for the Marburg virus.

Based on the available information and current risk assessment, WHO advises to strengthen surveillance in the country through alert management, case investigation, contact listing, tracing and follow up and active case search. In addition, WHO advises to strengthen surveillance at points of entry in the affected areas in Equatorial Guinea and the United Republic of Tanzania for the identification of cases, including through exit screening; to map cross-border population mobility to identify populations in vulnerable situations and target public health interventions; and to provide public health information and advice in all relevant languages in affected districts, at points of entry and in adjacent communities near land borders. Furthermore, suspect, probable and confirmed cases and their contacts should not undertake travel, including international. Based on available information, WHO advises against any other international travel and/or trade measures in Equatorial Guinea and the United Republic of Tanzania. States Parties adopting international travel- and trade-related measures potentially more restrictive than those advised by WHO, are invited to report them to WHO, pursuant to Article 43 of the International Health Regulations (2005).

Before initiating discussion on the 42-day countdown to declare the end of an outbreak, it is recommended that all listed contacts of confirmed or probable cases have completed their 21-day follow-up period with no symptoms. If not, there is still a possibility that a contact becomes a case.