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Interpreting this report

The UK Health Security Agency’s (UKHSA) Emerging Infections and Zoonoses (EIZ) team uses an integrated horizon scanning approach, which combines information on both human and animal health, to identify and assess outbreaks and incidents of new and emerging infectious diseases globally. For further information about the EIZ team’s horizon scanning process, please see our Epidemic intelligence activities.

This summary provides an overview of incidents (new and updated) of public health significance, which are under close monitoring. The incidents are divided into 2 sections: Notable incidents of public health significance and Other incidents of interest. For each notable incident of public health significance, an incident assessment is provided, based on the EIZ team’s interpretation of the available information.

The report also includes a section that focuses on Novel pathogens and diseases and a final Publications of interest section, which contains new publications relevant to emerging infections.

Epidemiological updates for diseases classified as a high consequence infectious disease (HCID) are published in UKHSA’s HCID monthly summary, unless they are considered a notable incident of public health significance, in which case a more detailed summary will be provided in this report.

For more information, or to sign up to the distribution list to receive an email alert when new reports are published, please contact epiintel@ukhsa.gov.uk

Notable incidents of public health significance

Summary of incidents

Disease or infection	Location	New or update since the last report
Marburg virus disease	Tanzania	Update
Sudan virus disease	Uganda	Update

Marburg virus disease (MARD) – Tanzania

Event summary

On 13 March 2025, Tanzania’s Ministry of Health (MoH) , 42 days (2 consecutive incubation periods of the virus) after the last confirmed case died on 28 January 2025. The outbreak had officially been confirmed on , and resulted in 10 cases (2 confirmed, 8 probable), all of which were fatal.

All of the cases were identified in Biharamulo District, Kagera Region, and were aged between 1 to 75 years old. Up to 12 March 2025, a total of had been followed up, of which 9 were later classified as probable or confirmed cases. The World Health Organization (WHO) report that investigations are planned to determine the source of the outbreak. A on MVD in Sub-Saharan Africa revealed a close genetic relationship between Marburg virus (MARV) strains isolated from Egyptian fruit bats and those found in humans during previous outbreaks. These findings reinforce the role of the Egyptian fruit bat, a species widely distributed across the region including Tanzania, as a significant zoonotic reservoir for MARV in Sub-Saharan Africa.

During this outbreak, Tanzania’s MoH developed a , with technical and operational support from the WHO. Activities included the deployment of rapid response teams, surveillance activities such as airport surveillance and contact tracing, the deployment of a mobile laboratory for rapid testing, and community awareness campaigns.

Incident assessment

This is the second MVD outbreak in Tanzania’s Kagera Region, with the first occurring between , resulting in 9 cases (8 confirmed) and 6 deaths (case fatality rate (CFR) of 67%). The source of exposure in both the previous and latest outbreaks have not yet been identified. Fruit bats, which are a zoonotic reservoir for MARV, are endemic to the area and could present an ongoing risk for future spillover events. On 13 March 2025, the WHO assessed the risk of the latest outbreak as moderate at a national level, and low at the regional and global levels.

No travel associated cases of MVD have been reported in the UK. The UKHSA’s Returning Workers Scheme was activated in response to this outbreak, which aimed to monitors the health of individuals who deploy to affected areas where they may be exposed to MVD as part of their work. Further information on MVD can be found on UKHSA’s Marburg virus disease: origins, reservoirs, transmission and guidelines webpage.

Sudan virus disease (SVD) - Uganda

Event summary

On 19 March 2025, initiated the 42-day countdown to the end of the Sudan virus disease (SVD) outbreak, following the recovery and discharge of the last 2 confirmed hospitalised cases. The 42-day countdown accounts for 2 consecutive incubation periods of the virus. Since the official confirmation of the outbreak on 30 January 2025, , including 4 deaths (CFR of 29%) have been reported in Uganda.

On 1 March 2025, the Ugandan MoH aged under 5 years old in Mulago Hospital, Kampala. Investigations identified 2 additional probable cases associated with this case (the mother of the confirmed case and her newborn child), both of which were fatal. The latest confirmed cases were reported on in adult females; both cases were contacts of a previously confirmed case and were admitted to treatment facilities. In this outbreak, cases have been identified across 6 districts (Jinja, Kampala, Kyegegwe, Mbale, Ntoroko and Wakiso). Confirmed cases have been recorded in individuals aged between 1.5 and 55 years old, with males accounting for 55% of the total cases.

The Ugandan MoH, with support from the WHO, implemented a variety of to control the outbreak, including the activation of an incident management team, and the dispatch of rapid response teams to affected districts. A national response plan was developed to identify priorities and to build on lessons learned from previous outbreaks.

Incident assessment

Sudan virus is one of 4 orthoebolavirus species that cause Ebola disease in humans. This is the 8th Ebola disease outbreak in Uganda, with 6 (one in 2000, one in 2011, 2 in 2012, one in 2022, and the current outbreak) due to SVD. Historically, CFR for SVD outbreaks has been between 41% and 70%. A previous SVD outbreak in Uganda that occurred between resulted in 164 cases and 77 deaths (CFR of 47.0%). ±«²µ²¹²Ô»å²¹â€™s MoH have experience of responding to Ebola disease outbreaks and promptly established response measures to control the current outbreak. On 8 March 2025, the WHO assessed the , as there are no licensed vaccines or therapeutics for the prevention and treatment of SVD.

The UKHSA has activated the Returning Workers Scheme in response to this outbreak, aimed at monitoring the health of those deploying overseas who may be exposed to SVD through their work. A range of robust clinical, infection prevention and control measures are available in the UK for imported cases of SVD which can be adapted for use as necessary to reduce the risk of transmission. The UKHSA has also published UK-specific clinical management guidelines and additional information on SVD.Ìý

Summary of other incidents

Disease or infection	Location
Chikungunya	Reunion
Cholera	African Region, Haiti
Measles	Canada, United States
Oropouche fever	Brazil, Panama
Poliovirus	Multi-country
Undiagnosed illness	Democratic Republic of the Congo
Yellow fever	Americas Region

Chikungunya

Since the start of the outbreak on 23 August 2024, and up to 20 March 2025, and 2 deaths have been reported in Reunion. Between 24 and 30 March 2025, 6,289 new confirmed cases were reported, of which most were in Le Tampon Municipality (800 cases). Prior to this outbreak, the last locally acquired chikungunya case in Reunion was recorded in 2014. Travel associated cases from Reunion have since been .

Cholera

Between 1 January and 28 March 2025, were reported across 13 African Union member states. Most cases have been reported from South Sudan (17,396 cases and 375 deaths) and Sudan (7,319 cases, and 139 deaths). To compare, during 2024, a total of 236,874 cholera cases (including 30,597 confirmed cases) and 4,182 deaths (CFR of 1.8%) were reported across 20 African Union member states.

Angola has been experiencing a cholera outbreak since January 2025. According to the WHO, as of 23 March, a total of (CFR of 3.9%) have been reported across 16 out of 21 provinces nationally. Most cases have been reported in Luanda Province (4,143 cases), followed by Bengo Province (2,485 cases). The 6 to14 years old (1,976 cases), and 15 to 24 year old (1,850 cases) age groups have been disproportionately affected. The last major cholera outbreak in Angola was recorded in 2006, with over 67,000 cases and 2,700 deaths.

On 11 March 2025, the reported a confirmed cholera case in a 55 year old female. The case experienced symptom onset on 2 March 2025, and was confirmed on 10 March 2025. Investigations found that the case had no recent travel history outside of the country and had not attended any large public gatherings. This is the first confirmed cholera case in Namibia in 10 years.

In 2025, as of 28 March 2025, the United Nations Office for the Coordination of Humanitarian Affairs reported in Haiti, of which most have been recorded in the conflict affected area of Port-au-Prince. On 20 March 2025, cholera cases were also confirmed in 3 internally displaced persons camps.

Measles

Canada is currently experiencing a multijurisdictional measles outbreak which began in New Brunswick during October 2024. As of , 722 cases (578 confirmed, 144 probable) have been reported, with most cases recorded in Ontario (660 cases). In 2025, most cases have been reported amongst individuals aged 5 to 17 years old (321 cases), and amongst unvaccinated individuals (582 cases). Between 1998 and 2024, an average of 91 measles cases were reported in Canada annually.

The US has also been experiencing a measles outbreak in 2025. As of 29 March 2025, , of which over 250 cases have been recorded in Texas. During this period, 2 associated deaths were reported in Texas and New Mexico (one each). This is the largest number of reported measles cases in the US since 2019 (1,274 cases). The from the Pan American Health Organization (PAHO) assessed the risk of measles in the Americas Region as high.

Oropouche fever

According to the , between 1 January and 31 March 2025, 7,320 confirmed cases of Oropouche fever and one suspected death were reported in Brazil. During this period, most cases were reported in Espirito Santo (5,354 cases). To compare, a total of 13,791 confirmed cases and 4 deaths were reported in Brazil during 2024.

On 10 March 2025, the reported the first confirmed fatal case of Oropouche fever in the country in an 82 year old male with underlying health conditions and a history of travel to Darien Province. A total of 207 Oropouche fever cases were reported in Darien Province between 24 February and 2 March 2025.

Poliovirus

Wild poliovirus type 1 (WPV1)

During March 2025, 3 new WPV1 cases were reported in Pakistan by the Global Polio Eradication Initiative (GPEI). This brings the reported in Pakistan during 2025 to 6 cases, as of 26 March. In 2024, 74 cases of WPV1 were reported from Pakistan.

Circulating vaccine derived polio virus (cVDPV)

During March 2025, the GPEI reported from: Angola (2 cases), Cameroon (one case), Chad (7 cases), the Democratic Republic of the Congo (DRC), (one case), Djibouti (one case), Nigeria (14 cases) and Somalia (4 cases). A total of in 2024 with most cases reported from Nigeria (98 cases), Ethiopia (42 cases), and Chad (39 cases).

Undiagnosed illness

On 3 March 2025, the WHO reported a , Equateur Province, DRC. Initially, 24 deaths due to an undiagnosed illness with symptoms of acute febrile illness were reported in a village in Basankusu Health Zone on 9 February 2025. By 15 March 2025, a total of had been reported. Although deaths had occurred in all age groups, children and young people were predominantly affected. Initial samples taken from cases had tested negative for Ebola and Marburg viruses, however approximately 50% of samples had tested positive for malaria. On 25 March 2025, that according to the DRC’s National Public Health Institute, malaria was the cause of the outbreak.

Yellow fever

On 26 March 2025, an epidemiological alert for yellow fever in the Americas Regions following a recent increase in human cases. In 2025, up to 22 March, a total of 131 confirmed human cases, including 53 deaths, were reported in the region. Most cases were reported in Brazil (81 cases, 31 deaths), Colombia (31 cases, 13 deaths), Peru (18 cases, 8 deaths), and Bolivia (one fatal case). To compare, during 2024 a total of were reported in the Americas Region.

Publications of interest

Ebolavirus

Obeldesivir (ODV) is an oral prodrug with broad-spectrum antiviral activity, a evaluating its use as a postexposure treatment for Ebolavirus found that daily oral ODV treatment for 10 days provided 80% protection in cynomolgus macaques and 100% protection in rhesus macaques when administration was started 24 hours after mucosal exposure to Ebolavirus. As a result, viral replication was delayed, subsequently reducing inflammation and enhancing an adaptive immune response. The findings highlight ODV’s potential as a convenient, oral postexposure prophylactic option for filoviruses, offering logistical advantages over intravenous therapies.

West Nile virus

The authors of a recent study reported on the phylogenetic and phylogeographic analyses of the first West Nile virus (WNV) strain , collected in mid-September 2024. This isolate was classified within lineage 1a and revealed that the virus likely originated in Africa and reached Portugal via the Cádiz coast of Spain, following the patterns of migratory birds. The study highlights a likely path from West Africa through Senegal, Mauritania, Morocco, Portugal, Spain, Italy, and France, with evidence of reciprocal viral movement back into Africa. Although WNV is already considered to be endemic in Portugal, with annual outbreaks particularly affecting horses, these findings underscore the significant role of migratory birds in the long-distance dispersal and reintroduction of WNV across continents.

Another study modelled the influence of in six Culex mosquito species, a key factor in predicting the risk of vector-borne diseases under climate change. The authors found 24°C to be the optimal temperature for WNV transmission, although a degree of variability was noted between mosquito species as well as intra-species resulting in scenarios where the optimal temperature differed by 3°C. The study highlights the need for further surveillance regarding the biting rate, lifespan, vector competence, and egg viability of different mosquito species to more accurately improve WNV transmission predictions in a changing climate.

Further reading

UKHSA Priority pathogen families research and development tool

Infectious diseases impacting England: 2025 report

Related resources

1.ÌýHigh consequence infectious diseases monthly summaries

2.ÌýNational flu and COVID-19 surveillance reports

3.ÌýAvian influenza (influenza A H5N1): technical briefings

4.ÌýAvian influenza (bird flu) in Europe, Russia and the UK reports

5.ÌýBird flu (avian influenza): latest situation in England updates

6.ÌýHuman Animal Infections and Risk Surveillance (HAIRS) group risk assessments and statements

7.ÌýAnimal and Plant Health Agency (APHA) monitoring of disease in livestock and poultry monthly reports

Authors of this report

UKHSA’s Emerging Infections and Zoonoses team epiintel@ukhsa.gov.uk