Situation at a glance
On 13 March 2025, the Ministry of Health of the United Republic of Tanzania declared the end of the Marburg virus disease (MVD) outbreak.
This declaration came after two consecutive incubation periods (a total of 42 days) since the last person confirmed with MVD died on 28 January 2025 and was given a safe and dignified burial, in accordance with WHO recommendations.
No new confirmed cases were reported since then.
The outbreak was declared on 20 January 2025. As of 12 March 2025, two confirmed and eight probable cases were reported by the Ministry of Health from Biharamulo district in Kagera region. All 10 cases died (case fatality ratio 100%), including eight who died before the confirmation of the outbreak. A total of 272 contacts that were listed for monitoring completed their 21-day follow-up as of 10 February 2025. WHO, through its country office, and partners provided technical, operational and financial support to the government to contain this outbreak. The risk of re-emergence of MVD remains after the official declaration of the end of the outbreak, linked to the animal reservoir’s presence in the country. WHO encourages maintaining early case detection and care capacities in addition to sustaining the ability to quickly respond, and continued risk communication and community engagement.
Description of the situation
Since the last Disease Outbreak News on this event, published on 14 February 2025, no new confirmed cases of Marburg virus disease (MVD) have been reported in the United Republic of Tanzania.
As of 12 March 2025, 10 cases have been reported including two confirmed and eight probable cases. All cases resulted in deaths, including eight who died before the confirmation of the outbreak and were classified as probable cases, resulting in a case fatality ratio of 100%.
The first identified case, an adult female, had symptom onset on 9 December and died on 16 December 2024. The last confirmed case died on 28 January, and a safe and dignified burial was performed. No new confirmed or probable cases have been reported following this burial. All 10 cases were reported from Biharamulo district in Kagera region; the median age of cases was 30 years (range: 1 to 75 years) and the majority of cases (70%, 7) were females.
Cumulatively, 108 suspected cases were reported between 20 January and 11 March, of which 106 tested negative for MVD.
As of 12 March 2025, 281 contacts had been listed, including nine who were subsequently classified as probable and confirmed cases and 272 contacts who completed 21 days of follow-up.
On 13 March 2025, after two consecutive incubation periods (a total of 42 days) without a new confirmed case being reported after the last confirmed case died on 28 January 2025, the Ministry of Health of the United Republic of Tanzania declared the end of the MVD outbreak, as per WHO recommendations.
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Epidemiology
MVD is a highly virulent disease that can cause severe disease and is clinically similar to Ebola disease (EBOD). EBOD and MVD are caused by orthoebolaviruses and orthomarburgviruses respectively; both are members of the Filoviridae family (filovirus). People become infected after prolonged exposure to mines or caves inhabited by Rousettus fruit bat colonies, a type of fruit bat that can carry the Marburg virus. Marburg virus then 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 (e.g. bedding, clothing) contaminated with these fluids. Health workers have previously been infected while treating patients with 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 the Marburg virus begins abruptly, with a high fever, severe headache, and severe malaise. Severe watery diarrhoea, abdominal pain and cramping, nausea, and vomiting can begin on the third day. Although not all cases present with haemorrhagic signs, severe haemorrhagic manifestations may appear between five and seven days from symptom onset, and fatal cases usually have some form of bleeding, often from multiple areas of the body. In fatal cases, death occurs most often between eight and nine days after symptom onset, usually preceded by severe blood loss and shock. There is currently no approved treatment or vaccine for MVD. Some candidate vaccines and therapeutics are currently under investigation.
Eighteen outbreaks of MVD have previously been reported globally. The most recent outbreak was reported in Rwanda between September and December 2024. Additional countries that previously reported outbreaks of MVD in the African Region include Angola, the Democratic Republic of the Congo, Equatorial Guinea, Ghana, Guinea, Kenya, South Africa, and Uganda.
Public health response
The Ministry of Health developed a national response plan to guide response activities.
A National Incident Management System was activated to coordinate the response to the event; a national task force was activated, and meetings were held weekly. At the sub-national level, regular coordination meetings were held daily in Kagera Region.
A national rapid response team was deployed to Kagera to enhance outbreak investigation and response, with technical and operational support from WHO and health partners.
WHO deployed experts to support the Ministry of Health with Emergency management and partner coordination, clinical management, health logistics, infection prevention and control, and other response activities in different pillars.
Surveillance activities were conducted with active case finding, contact tracing and mortality surveillance across affected and neighbouring areas.
The mobile laboratory deployed in Kabyaile was utilized to support the testing of suspect cases for rapid turnaround time, and samples were referred to the National Public Health Laboratory in Dar es Salaam for additional tests.
Travellers departing from the Kagera Region were screened at key points of entry and exit, including Bukoba airport.
Health and care worker sensitization sessions on infection prevention and control were conducted across Kagera and other regions.
The Marburg Treatment Unit was upgraded with enhanced triage, patient wards, and donning and doffing areas.
Public awareness campaigns were conducted, including health education, door-to-door outreach by community health workers, and public announcements in high-risk areas.
Cross-border meetings were convened between Tanzania, Uganda, and Burundi.
WHO procured and delivered four VHF kits to Kagera region to support care for patients and infection prevention and control measures.
WHO risk assessment
With two confirmed cases and eight probable cases reported, this is the second MVD outbreak reported in the country in the last three years. Both outbreaks occurred in the same region of Kagera located at the border with Rwanda and Uganda.
The case fatality ratio of 100% is concerning, although has been recorded in previous outbreaks, additionally 8 of the 10 cases were probable i.e. reported after their death. Late health seeking behaviour in MVD outbreaks increases the risk of further transmission.
The source of the outbreak is still unknown, and research activities are planned. Based on the outbreak investigation and surveillance activities during the response, which included contact tracing, alert management, active case search, and mortality surveillance, no additional cases have been reported during the 42-day countdown period. However, there remains a risk of re-emergence of MVD following the declaration of the end of the outbreak, linked to a new spillover from interactions with the animal reservoir.
Based on the available information at the end of MVD outbreak in Tanzania, the risk is considered as moderate at the national level, and low at regional and global levels.
WHO advice
WHO encourages maintaining early detection and care capacities in addition to sustaining the ability to quickly respond after the outbreak ends. This is to make sure that if the disease re-emerges, health authorities can detect it immediately, prevent the disease from spreading again, and ultimately save lives.
Raising awareness of risk factors for Marburg virus infection and protective measures that individuals can take is an effective way to reduce human transmission. WHO advises the following risk reduction measures as an effective way to reduce MVD transmission in healthcare facilities and in communities:
-- Reducing the risk of bat-to-human transmission arising from prolonged exposure to mines or caves inhabited by fruit bat colonies. People visiting or working in mines or caves inhabited by fruit bat colonies should wear gloves and other appropriate protective clothing (including masks).
-- Capabilities for early detection of MVD patients should be maintained over time in settings at risk of the disease.
-- Reducing the risk of human-to-human transmission in the community arising from direct or close contact with infected patients, particularly with their body fluids. Close physical contact with MVD patients should be avoided. Patients suspected or confirmed for MVD should be isolated in a designated treatment centre for early care and to avoid transmission at home.
-- Communities affected by MVD, along with health authorities, should ensure that the population is well informed, both about the nature of the disease itself and about necessary outbreak containment measures.
-- Outbreak containment measures include safe and dignified burial of the deceased, identifying people who may have been in contact with someone infected with MVD and monitoring their health for 21 days, separating the healthy from the sick to prevent further spread and providing care to the confirmed patient. Maintaining good hygiene and a clean environment need to be observed.
-- Critical infection prevention and control measures should be implemented and/or strengthened in all health care facilities, per WHO’s Infection prevention and control guideline for Ebola and Marburg disease. Health workers caring for patients with confirmed or suspected MVD should apply transmission-based precautions in addition to: standard precautions, including appropriate use of PPE and hand hygiene according to the WHO 5 moments to avoid contact with patient’s blood and other body fluids and with contaminated surfaces and objects. Waste generated in healthcare facilities must be safely segregated, collected, transported, stored, treated and finally disposed. Follow the national guidelines, rules and regulations for safe waste disposal or follow the WHO’s guidelines on safe waste management.
-- Patient-care activities should be undertaken in a clean and hygienic environment that facilitates practices related to the prevention and control of health-care-associated infections (HAIs) as outlined in Essential environmental health standards in health care. Safe water, adequate sanitation and hygiene infrastructure and services should be provided in healthcare facilities. For details on recommendations and improvement, follow the WASH FIT implementation Package
-- WHO encourages countries to implement a comprehensive care programme to support people who have recovered from MVD (if any) with any subsequent sequelae and to enable them to access body fluid testing and to mitigate the risk of transmission through infected body fluids by adequate practices.
Based on the current risk assessment, WHO advises against any travel and trade restrictions with the United Republic of Tanzania.
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Source: World Health Organization, https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON559
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