Disease Outbreak News Sudan virus disease - Uganda

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8 March 2025

Situation at a glance

Since the outbreak of Sudan virus disease (SVD) was declared in Uganda on 30 January 2025, and as of 5 March 2025, a total of 14 cases (including 12 confirmed cases and two probable cases) including four deaths (two confirmed and two probable) have been reported. On 1 March 2025, the Ministry of Health released a press statement confirming the tenth case. The patient was a child under 5 years old who presented and died in the Mulago hospital ion 23 February 2025. As of 5 March, two additional confirmed cases and two probable deaths have been reported that are linked to this case. Both of these cases are currently admitted to treatment facilities. Eight confirmed cases received care at treatment centres in the capital Kampala and in Mbale and were discharged on 18 February 2025. As of 5 March 2025, 192 new contacts have been identified and are under follow-up in Kampala, Ntoroko and Wakiso. In the absence of licensed vaccines and therapeutics for the prevention and treatment of SVD, the risk of potential serious public health impact is high.

Description of the situation

Since the second disease outbreak news on this event published on 21 February 2025, three additional laboratory-confirmed cases and two probable deaths of SVD have been reported in Uganda. As of 5 March 2025, 12 confirmed and two probable cases, among these four deaths (two confirmed, two probable) have been reported with a case fatality ratio (CFR) of 29%. The latest confirmed cases are reported to be epidemiologically linked to the two probable cases. The age range of confirmed cases is 1.5 years to 55 years, with a mean age of 27 years and males accounted for 55% of the total cases. The cases were reported from six districts in the country which include Jinja, Kampala, Kyegegwe, Mbale, Ntoroko and Wakiso (Figure 1).

On 1 March 2025, the Ministry of Health released a press statement about the confirmation of a new case. The case was an under 5-year-old child identified at the Mulago Hospital where the patient presented with signs and symptoms meeting the suspect case definition. A laboratory sample was collected, and the child was confirmed with SVD on 26 February by PCR. Following investigations, two probable deaths linked to this case have been reported. This includes the child’s mother who was pregnant at the time of symptom onset on 22January and died on 6 February. Her newborn child died on 12 February. The three deaths did not have a supervised burial. On 3 March, an 11^th case was confirmed, an adult female, contact of case 10, and on 4 March, a 12^th case was confirmed, an adult female, contact of the probable case (the mother of case 10). Both of these cases are currently admitted to treatment facilities.

Since the start of the outbreak, eight cases have recovered and been discharged.

Figure 1: Distribution of Sudan virus disease confirmed, and probable cases reported from Uganda between 30 January and 5 March 2025

Figure 2: Epidemiological curve of reported confirmed SVD cases by symptom onset date, data as of 5 March 2025, (n=12)

As of 5 March, there are 192 new contacts listed around the new cases and 299 previously listed contacts who had completed the 21-day follow-up period.

SVD alert levels reported from the community and the health facilities have been low and efforts are ongoing to improve this. Mortality surveillance has also been set up since the declaration of the outbreak and will continue in Jinja, Kampala, Mbale, Ntoroko and Wakiso districts.

Retrospective epidemiological and laboratory investigations are ongoing to find the source of the outbreak while active case search in and around the community and health facilities linked to the case movements have been intensified.

Epidemiology

Sudan virus disease is a severe disease, belonging to the same family as Ebola virus disease. It is caused by Sudan virus (SUDV) and can result in high case fatality. It is typically characterized by acute onset of fever with non-specific symptoms/signs (e.g., abdominal pain, anorexia, fatigue, malaise, myalgia, sore throat) usually followed several days later by nausea, vomiting, diarrhoea, and occasionally a variable rash. Hiccups may occur. Severe illness may include haemorrhagic manifestations (e.g., bleeding from puncture sites, ecchymoses, petechiae, visceral effusions), encephalopathy, shock/hypotension, multi-organ failure, and spontaneous abortion in infected pregnant women. Individuals who recover may experience prolonged sequelae (e.g., arthralgia, neurocognitive dysfunction, uveitis sometimes followed by cataract formation), and clinical and subclinical persistent infection may occur in immune-privileged compartments (e.g., central nervous system (CNS), eyes, testes). Person-to-person transmission occurs by direct contact with blood, other bodily fluids, organs, or contaminated surfaces and materials with risk beginning at the onset of clinical signs and increasing with disease severity. Family members, healthcare providers, and participants in burial ceremonies with direct contact with the deceased are at particular risk. The incubation period ranges from 2 to 21 days, but typically is 7–11 days.

Public health response

Health authorities are implementing public health measures, including but not limited to the following:

Coordination:

The Ministry of Health (MoH) has activated the coordination structures at national and subnational levels, including the Incident Management Team and dispatched Rapid Response Teams to the affected districts. Regional Emergency Operation Centers have been activated in Fort Portal, Ntoroko, Kampala, and Mbale districts.
The country developed a National Response Plan (February-April 2025). The response plan has been updated to reflect current response priorities and builds on lessons learned from previous outbreaks. It deploys the basic minimum packages of activities across the districts according to risk.

Surveillance and contract tracing:

MoH with support from WHO and partners, is conducting alert management including the setup of an alert desk with toll-free numbers to detect and verify alerts from all over the country that meet the case definition. Since 30 January, over 1300 signals have been reported from all over the country and 112 alerts have been verified as suspected cases.
MoH with support from partners has allocated teams to conduct detailed case investigations around all confirmed and probable cases to identify and stop the chains of transmission.
MoH has allocated teams to conduct contact listing of cases and perform daily follow-up of contacts.
Following the declaration of the outbreak, MoH, with support from WHO, has established mortality surveillance. Over 770 non-trauma deaths were tested in communities and health facilities located in the affected districts, and one tested positive (case 10).
MoH set up a hotline for notification of suspected cases.
MoH is conducting exit screening of SVD signs and symptoms among travellers at Uganda’s 13 high volume points of entry (POE) including Entebbe International Airport

Case Management:

MoH with support from WHO and partners has set up four designated isolation and treatment units in Jinja, Kampala, Mbale and now Fort Portal, where confirmed cases receive optimized supportive care. Plans are underway to conduct therapeutic clinical trials.
Patients who recovered from the disease are included in the survivor care programme for support and care.
MoH has scaled up its case management strategy to ensure sufficient capacities to provide care for all suspected and confirmed cases in all hot spots

Laboratory:

MoH and partners have strengthened laboratory capacities and deployed a mobile laboratory to Mbale to reduce turnaround time for laboratory results.
MoH has performed a full genome sequencing on the sample of the first confirmed case and findings indicate the outbreak is most likely the result of a spillover event. Sequencing was also performed on samples of subsequent confirmed cases,

Infection prevention and control:

MoH has activated their IPC response coordination mechanism.
MoH has activated the IPC ring around cases, which includes cleaning and disinfection of sites where confirmed cases passed through.
In their official press statement, the MoH provided recommendations to health workers, district leaders, and the public to strengthen detection of suspected cases and implement appropriate infection, prevention and control measures.
MOH is surging and strengthening IPC activities, with the support of partners, notably to improve screening, isolation and notification at health facilities in order to better detect suspected cases.
MoH is orienting health workers on IPC measures in the context of Ebola disease outbreak response.

Risk communication and community engagement (RCCE)

An integrated community engagement approach has been adopted whereby the RCCE team facilitate access to communities for other response pillars. This helps to build trust and enhance contact tracing, case investigation, surveillance, referral to isolation units and provision of psychosocial support.
Anthropological investigation is used to identify community concerns, risk behaviours, reduce hesitancy from communities and to enhance evidence-informed decisions across pillars.
Development and dissemination of public health messages to promote protective and health seeking behaviours, community engagement to build trust and provide psychosocial support.

Research and development

Research priorities: The Collaborative Open Research Consortium (CORC) for the Filoviridae Family held two global consultations to deliberate and identify the research priorities for Sudan ebolavirus in general and this outbreak in particular. Over 200 scientists from around the world participated in each of the two consultations.

Ring vaccination trial: After the outbreak was confirmed on 30 January, researchers from the Uganda Makerere University and the Virus Research Institute (UVRI), with support from WHO, swiftly mobilised to launch the vaccination trial. The trial was initiated only four days following the outbreak, reflecting the urgency of the response while maintaining rigorous ethical and regulatory standards. The trial follows the ring vaccination model, in which primary and secondary contacts of confirmed cases receive the vaccine, to create a protective barrier and help break chains of transmission.The development of the protocols and research priorities has been done via the MARVAC Consortium and the Collaborative Open Research Consortium (CORC) for the Filoviridae Family, European Union (EU) Health Emergency Preparedness and Response (HERA) and Canada’s International Development Research Centre (IDRC) supported the development of these crucial trial protocols during the inter-epidemic, preparedness phase
EU HERA and IDRC also provided financial support for the trial, alongside WHO. The Coalition for Epidemic Preparedness Innovations (CEPI) is also providing support with additional support from the Africa Centres for Disease Control and Prevention (Africa CDC). The vaccine itself was donated by IAVI, with additional support from the Africa CDC.
Therapeutics trial: While several promising candidate therapeutics are currently advancing through clinical development, no licensed treatment is yet available to effectively address potential future outbreaks of Ebola virus disease caused by the Sudan virus species. If successful, this trial could play a critical role in enhancing outbreak control measures and supporting the future regulatory approval of the candidate vaccine. Numerous developers facilitated the availability of the candidate vaccine and treatments: MappBio provided their candidate Sudan monoclonal, Gilead provided remdesivir, an antiviral.

WHO is supporting the national authorities through:

Risk assessment and investigation.
Providing operational, financial and technical support to the Ministry of Health to ensure swift response. A total of US$ 3.4 million was released from the Contingency Fund for Emergencies for the three levels of WHO to support the government-led response
Supporting the national laboratory system to implement sample collection, transport and diagnostic testing.
Providing strategic, technical and operational support to strengthen infection. prevention and control response measures and standards within health facilities and Ebola treatment units in Kampala, Mbale, Luwero districts. This includes supporting IPC ring activation activities, rapid assessments of health facilities, capacity building of health workers, mentorship and supportive supervision at designed health facilities and supporting development of key guidance, SOPs and tools.
Facilitating access to candidate vaccines and therapeutics and supporting the launch of the vaccine trial. Rings have been defined around all confirmed cases and their contacts have been invited to consent in the trial. As part of this support, the “TOKEMEZA SVD” vaccine trial was launched on 3 February 2025 and the TOKOMEZA immuno (an add-on study) was launched on 1 March 2025.
Providing technical and operation assistance for the setup of isolation centers for suspected cases and two Ebola treatment units in Kampala and Mbale.
Mobilizing logistics to complement government supplies, including IPC supplies, drugs, resuscitation and monitoring equipment, admission packages, and mattresses.
Deploying a team of 47 experts to Mbale, Kampala, Wakiso and Jinja districts to support across different response pillars including coordination, surveillance, laboratory, logistics, IPC, RCCE, and case management pillars.
Supporting RCCE efforts to counter misinformation and enhance community engagement through the deployment of two anthropologists.
Intensified and integrated risk communication and community engagement, including sensitization and training of Village Health Teams, traditional healers, religious leaders and teachers.
Collecting social and behavioural data and using evidence to respond to communities’ anxieties and concern, rumours, misinformation and disinformation

WHO risk assessment

Sudan virus disease (SVD) is a severe, often fatal illness affecting humans. Sudan virus (SUDV) was first identified in southern Sudan in June 1976. Since then, the virus has emerged periodically and up to now and prior to this current one, eight outbreaks caused by SUDV have been reported, five in Uganda and three in Sudan. The case fatality rates of SVD have varied from 41% to 70% in past outbreaks.

SUDV is enzootic and present in animal reservoirs in the region. Uganda reported five SVD outbreaks (one in 2000, one in 2011, two in 2012, and one in 2022). The current outbreak is the sixth SVD outbreak in Uganda. Uganda also reported a Bundibugyo virus disease outbreak in 2007 and an Ebola virus disease outbreak exported from the Democratic Republic of the Congo in 2019. The latest SVD outbreak in Uganda was declared over on 11 January 2023. A total of 164 cases with 55 deaths were reported in nine districts.

Uganda has experience in responding to Ebola disease outbreaks including SVD. In the ongoing outbreak, cases have been reported from several districts including the capital city, Kampala, with high population movement. Cases have sought care in several health facilities, including traditional healers, and some cases have been detected at a late stage of the disease or death. The government, with support from partners is implementing several public health actions for effective control.

In the absence of licensed vaccines and therapeutics for the prevention and treatment of SVD, the risk of potential serious public health impact is high. Community deaths, care of patients in private facilities and hospitals and other community health services as well as at traditional healers with limited protection and infection prevention and control measures entail a high risk of many transmission chains. An investigation is ongoing to determine the source and the scope of the outbreak and the possibility of spread from the capital city, Kampala, to other districts. Exit screening has been set up at different points of entry to reduce the risk of potential exportation of cases to neighbouring countries.

WHO advice

Effective Ebola disease outbreak, including SVD, control relies on applying a package of interventions, including case management, surveillance and contact tracing, a strong laboratory system, implementation of infection prevention and control measures in health care and community settings, safe and dignified burials and community engagement and social mobilization.

Risk communication and community engagement is crucial to successfully controlling SVD outbreaks. This includes raising awareness of symptoms, risk factors for infection, protective measures and the importance of seeking immediate care at a health facility. Sensitive and supportive information about safe and dignified burials is also crucial. Awareness should be built through targeted campaigns and direct work with affected and proximate communities, with special attention to engage with traditional healers, clergy, ‘boda boda’ drivers and community leaders, who are important sources of information for the community. Findings from rapid qualitative assessments should continue to be implemented to collect socio-behavioural data, which can then be used to inform response pillars. Priority areas to strengthen, based on recent evidence are mortality surveillance, contact tracing and safe and dignified burials. Misinformation and rumours should be addressed to foster trust and promote early symptom reporting.

Early initiation of intensive supportive treatment increases the chances of survival. All above-mentioned interventions need to be thoroughly implemented in affected areas to stop chains of transmission and decrease disease mortality. Cases, contacts and individuals in affected areas who present signs and symptoms compatible with case definitions should be advised not to travel and seek early care at designated facilities to improve their chances of survival and limit transmission.

WHO encourages countries to implement a comprehensive care programme to support people who recovered from Ebola disease 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.

Collaboration with neighbouring countries should be enhanced to harmonize reporting mechanisms, conduct joint investigations, and share critical data in real-time. Surrounding countries should enhance readiness activities to enable early case detection, isolation and treatment.

A range of candidate vaccines and therapeutics are under different stage of development. Since 2020, WHO has convened scientific deliberations and set up an independent process to review candidate medical countermeasures (MCMs) prioritization and clinical trial designs. One candidate vaccine and two candidate therapeutics (a monoclonal antibody and an antiviral) have been recommended and are available in country and are being assessed (clinical efficacy and safety) through randomized clinical trial protocols.

Thanks to preparedness measures that the government took after the previous outbreak in 2022, and a global research collaboration led by WHO (first MARVAC now FILOVIRUS CORC), a trial of a candidate vaccine was launched just four days after the outbreak was declared. A therapeutics trial will start as soon as national authorities provide approval.

The two vaccines licensed against Ebola virus disease (from the Zaire species) will not provide cross-protection against SVD and cannot be used in this outbreak.

WHO advises against any restrictions on travel and/or trade to Uganda based on available information for the current outbreak.

Further information

Citable reference: World Health Organization (8 March 2025). Disease Outbreak News; Sudan virus disease in Uganda. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON558