Marburg virus disease - Equatorial Guinea

15 April 2023

This Disease Outbreak News was amended on 17 April 2023 to include information on partner coordination as part of the ongoing response measures.

Situation at a glance

Since the last Disease Outbreak News on this event was published on 22 March 2023 (with data as of 21 March 2023), six additional laboratory-confirmed cases of Marburg virus disease (MVD) have been reported in Equatorial Guinea. This brings the total to 15 laboratory-confirmed and 23 probable cases since the declaration of the outbreak on 13 February 2023. Among the laboratory confirmed there are 11 deaths (Case Fatality Ratio 78.6%; for one confirmed case the outcome is unknown), and all probable cases are dead. The most affected district is Bata in Litoral province, with nine laboratory-confirmed MVD cases reported.

WHO is supporting the Ministry of Health by strengthening different response pillars, including but not limited to surveillance, including at points of entry; laboratory; case management; infection prevention and control; risk communication and community engagement.

MVD is a disease with high mortality that causes haemorrhagic fever, and is among the diseases that require assessment under the International Health Regulations.

On 30 March 2023, WHO assessed the public health risk posed by this outbreak as very high at the national level, high at sub-regional level, moderate at the regional level and low at the global level.

WHO advises against restrictions to international travel and/or trade in Equatorial Guinea.

Description of the situation

On 13 February 2023, the Ministry of Health and Social Welfare of Equatorial Guinea declared an outbreak of Marburg virus disease (MVD) after suspected viral hemorrhagic fever deaths were reported between 7 January and 7 February 2023, and a case tested positive on 12 February for Marburg virus by real-time polymerase chain reaction (RT-PCR) at the Institute Pasteur in Dakar, Senegal.

Since the last Disease Outbreak News on this event (22 March 2023) and as of 11 April 2023, six additional laboratory-confirmed cases of MVD were reported in Equatorial Guinea, bringing the total of cases in the outbreak to 15 laboratory-confirmed. Additionally, 23 probable cases have been reported since the start of the outbreak. Eleven deaths were recorded among laboratory-confirmed cases (Case Fatality Ratio (CFR) among confirmed cases 78.6%), and all probable cases are dead; for one confirmed case the outcome is unknown. Four laboratory-confirmed cases (26.6%) were reported among healthcare workers, of whom two died. Among the confirmed cases, three have recovered.

Figure 1. MVD cases by week of onset* and case classification, Equatorial Guinea, as of 11 April 2023.

Among MVD laboratory-confirmed cases with age and sex information (n = 13), the majority occurred among females (9/14; 64.3%), while the most affected age group is 40-49 years (6/14; 42.8%), followed by the age groups 10-19 and 30-39 (three cases each).

Five districts (Bata, Ebebiyin, Evinayong, Nsok Nsomo and Nsork) in four provinces (Centro Sur, Kie Ntem, Litoral and Wele-Nzas) have been affected by the outbreak (Figure  2), with Bata district reporting the majority of confirmed cases (n = 9) and deaths (n = 6), and Ebebiyin district, where the outbreak was first detected, reporting the majority of probable cases,(n = 11) (Table 1).

In the last 21 days (from 22 March 2023 to 11 April 2023), five confirmed cases were reported from Bata (n = 4) and Nsork (n = 1) districts (Figure 3). Among the four cases reported from Bata district, three cases have an epidemiological link either through a family cluster or through health care setting. The fourth and most recent case was reported on 7 April; an investigation of this case is ongoing to establish transmission chains and ensure appropriate identification of all contacts.

Since the last Disease Outbreak News on this event, one new district, Nsork in Wele-Nzas province, has been affected by the outbreak, reporting one confirmed case, linked to a known case from another district that previously reported confirmed cases.

Since the start of the outbreak and as of 10 April 2023, a total of 1322 contacts have been listed, with an average follow-up rate around 80-90%.

Table 1. Number of MVD cases and deaths, by district and case classification, Equatorial Guinea, as of 11 April 2023.

Figure 2. Map of districts reporting MVD confirmed and probable cases as of 11 April, Equatorial Guinea.

Figure 3. Map of districts reporting MVD confirmed cases in the last 21 days (from 21 March 2023 to 11 April 2023), Equatorial Guinea.

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, clothing contaminated with these fluids. Healthcare workers have previously been infected while treating patients with suspected or confirmed MVD. Burial ceremonies that involve direct contact with the body of the deceased can also contribute to the transmission of Marburg virus. The incubation period varies from two to 21 days. Illness caused by 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, although 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 treat the virus, Remdesivir is being used on compassionate care bases. Supportive care – rehydration with oral or intravenous fluids – and treatment of specific symptoms improve survival. A range of potential treatments are being evaluated, including blood products, immune therapies, and drug therapies. This is the first time that Equatorial Guinea has reported an outbreak of MVD. Another MVD outbreak is currently taking place in Tanzania with a total of eight confirmed cases and five deaths as of 4 April 2023. 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 (1998 and 2000), Kenya (1990, 1987, 1980) and South Africa (1975).

Public health response

Coordination

  • The Government has activated a regional public health emergency operation center (PHEOC) in Bata under the leadership of the Minister of Health and the Minister Delegate.
  • A national operational response plan has been developed by the MoH.
  • Regular meetings are held by the MoH to coordinate response activities at national, regional and district level.
  • Partners from the Global Outbreak Alert and Response Network (GOARN) have been mobilized to assist response activities. In collaboration with Incident Management team GOARN issued Request for assistance on 30 March. Several experts are deployed and in process of being deployed to support case management, infection prevention and control, laboratory, and epidemiology and surveillance functions in the field.

Surveillance

  • WHO supported the Ministry of Health in setting up an alert and dispatch center for MVD alert management across the region.
  • WHO is supporting the Ministry of Health in training for surveillance activities, including case investigation, contact tracing, active case search in health facilities and the community, and in supervising field teams.
  • WHO is supporting the Ministry of Health in epidemiological data collection and management system, and developed and disseminated a reviewed case definition, validated by the Ministry of Health.

Laboratory

  • With the support of the US Centers for Disease Control and Prevention (CDC), and WHO, a laboratory with RT-PCR capacities has been set up in Bata for MVD diagnostic.  
  • WHO is supporting the implementation of a specimen transportation system, and discussions are on-going to support the establishment of sequencing capacities in the country.
  • Additional national staff are being trained on Marburg virus diagnostics by the WHO.

 Clinical care

  • WHO supported the Ministry of Health in the establishment an operational treatment and isolation centre in Bata, and is planning to open additional treatment facilities in other districts.
  • Assessments visits were carried out at identified treatment and isolation centers to identify and address gaps.
  • WHO is supporting awareness campaigns of clinical staff to help surveillance and reporting.

Infection Prevention and Control (IPC)

  • An IPC task force has been initiated, and a national IPC strategy is currently in draft form.
  • An IPC Scorecard for assessment of health facility IPC practices for readiness and response to Marburg has been implemented.
  • Trainings for health workers on IPC are in progress, including decontamination and safe and dignified burial teams (SBD).
  • Safe and dignified burials teams have been established in Bata and Ebibeyin.

Risk Communication and Community Engagement (RCCE)

  • WHO is coordinating with other key partners for joint support on RCCE activities (UNICEF, IFRC 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).
  • The recruitment of national RCCE consultants and deployment of an international expert have been conducted.
  • An RCCE national plan is under development and a rapid social behavioural survey is being prepared for implementation.
  • The Message Bank for Marburg has been developed and disseminated. The message bank is available in Spanish and English, with ongoing translation in Swahili, French and Portuguese.
  • A list of frequently asked questions and answers on Marburg virus disease, which will be accessible to the public, is under development.
  • WHO is providing technical support to the development of tools and education and communication (IEC) materials for preparedness in Gabon and Cameroon.

 Border health and points of entry

  • A needs and capacity assessment has been conducted to strengthen response capacities at points of entry through, for example, the development of contingency plans and standard operating procedures, the training of point-of-entry staff on the identification of signs and symptoms of MVD and the management of potential cases, implementation of risk communication and community engagement activities and the provision of handwashing and transportation capabilities.
  • WHO is working with the US Centers for Disease Control and Prevention (CDC) and the International Organization for Migration (IOM) on an upcoming webinar to raise awareness on the necessary border health readiness and response activities in the context of MVD outbreaks for affected and neighboring countries.

 Operational support and logistics (OSL)

  • ​WHO has established support for fleet management including two ambulances on standby 24/7 at the Bata treatment centr​e, and over 20 vehicles. WHO has provided essential medicines and supplies.

 Readiness and preparedness in neighboring countries

  • WHO has conducted a second readiness assessment across all pillars for the two surrounding countries, Cameroon and Gabon, and based on their gaps, activities to address them will be recommended including the deployment of experts to support the implementation of some of the readiness activities.
  • The WHO is working with Cameroon, Equatorial Guinea and Gabon to coordinate a high-level cross-border meeting.

WHO risk assessment

Equatorial Guinea is facing an outbreak of MVD for the first time and the country's capacity to manage the outbreak needs to be strengthened. In addition to the nine confirmed cases reported in the Disease Outbreak News of 22 March, six more individuals have tested positive for MVD, with an additional affected province. While many cases are linked within a social network or by geographic proximity, the presence of cases and/or clusters across multiple districts without clear epidemiologic links may indicate undetected transmission of the virus. The presence of confirmed cases in Bata increases the risk of disease spread, as it is the most populated city and economic hub of Equatorial Guinea, with an international airport and port. Bata has also reported the highest number of confirmed cases and confirmed deaths. The last case was also reported from Bata and investigation is ongoing to establish transmission chains. The country surveillance system remains suboptimal with few alerts reported and investigated. Several epidemiological links and transmission chains have not been detected, thus there might be contacts not identified.

Implemented infection prevention and control measures are insufficient as demonstrated by MVD cases reported among healthcare workers. The diagnostic capacity for Marburg virus in the country is limited in terms of the number of samples that can be analyzed per day (a maximum of around 50 a day). The community's perception of risk is estimated to be very low. There are frequent population movements between the different districts of the mainland region, as well as with the island region, despite the quarantine measures implemented in several of the affected areas. Frequent population movements and very porous land borders are also reported in the districts bordering Cameroon and Gabon, with surveillance at land entry points being suboptimal, and countless uncontrolled paths or trails along the border with Cameroon and Gabon. Also, surveillance at the entry points of the international Bata airport or international seaport, is not optimal. 

Considering the above-described situation, on 30 March 2023, WHO assessed the risk posed by this outbreak as very high at the national level, high at sub-regional level, moderate at the regional level and low at the global level.

WHO advice

Marburg virus disease outbreak control relies on using a range of interventions, such as prompt isolation and case management; surveillance including active case search, case investigation and contact tracing; an optimal laboratory service; infection prevention and control, including prompt safe and dignified burial; and social mobilization. Community engagement is key to successfully controlling Marburg disease 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 and care workers caring for patients with confirmed or suspected MVD should apply IPC measures including standard and transmission-based precautions 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. 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. Contact with body fluids should be avoided and washing with soap and water is recommended. 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 at points of entry in the affected areas in Equatorial Guinea 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 at points of entry and in adjacent communities near land borders. In addition, suspect, probable and confirmed cases and their contacts should not undertake travel, including international.

WHO advises against any other international travel and/or trade measures in Equatorial Guinea.

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).

Further information

 

Citable reference: World Health Organization (15 April 2023). Disease Outbreak News; Marburg virus disease - Equatorial Guinea. Available at https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON459