Research and analysis
Outbreaks under monitoring: week 36 (week ending 7 September 2025)
Updated 31 December 2025
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| Disease or pathogen | Chikungunya |
|---|---|
| Location | France |
| Reporting date | 3 September 2025 |
| Summary | Between 1 May and 2 September 2025, were recorded in mainland France. This is an increase of 73 cases since the . The reported number of locally acquired chikungunya cases in France is the highest since 2010. In the United Kingdom (UK), an increase in travel-associated chikungunya cases has been reported in 2025. Most cases reported travel to Sri Lanka, India and Mauritius. No locally acquired cases of chikungunya have ever been reported in the UK. |
| Further information |
Chikungunya: transmission, epidemiology and guidance Chikungunya: epidemiology in England, Wales and Northern Ireland |
| Disease or pathogen | Cholera |
|---|---|
| Location | Global |
| Reporting date | 26 August 2025 |
| Summary | On 29 August 2025, the World Health Organization (WHO) reported a deterioration in the that is being driven by conflict and other humanitarian crises. According to the WHO, 409,222 cholera and acute watery diarrhoea cases and 4,738 deaths (case fatality rate (CFR) of 1.2%) have been reported from 31 countries between 1 January and 17 August 2025. The highest number of cases have been registered in the Eastern Mediterranean region (230,991 cases and 943 deaths, CFR of 0.4%) and the highest number of deaths were reported in the African region (172,750 and 3,763 deaths, CFR of 2.2%). The number of fatalities recorded in 2025 is 46% higher when compared to the equivalent 2024 period (3,248 deaths reported globally from 28 countries). The WHO reported a resurgence of cholera in Chad and the Republic of the Congo, and a geographical expansion of cholera outbreaks in the Democratic Republic of the Congo (DRC), South Sudan, and Sudan. The in England and Wales was reported in 1893. Cholera is occasionally reported in . |
| Further information |
Cholera: guidance, data and analysis Travel-associated infections reports Green Book: Cholera Gastrointestinal infections: guidance for public health management |
| Disease or pathogen | Ebola virus disease |
|---|---|
| Location | Democratic Republic of the Congo (DRC) |
| Reporting date | 4 to 8 September 2025 |
| Summary | On 4 September 2025, the DRC’s Ministry of Health (MoH) of Ebola virus disease (EVD) in Kasai Province. This is the sixteenth EVD outbreak reported in the DRC. According to the WHO country office in the DRC, (CFR of 53.6%) have been reported as of 5 September 2025. Suspected cases have been reported in Bulape and Mweka health zones. Further reports have since indicated that 33 suspected cases and 16 deaths have been reported. The , a pregnant woman, presented to Bulape General Reference Hospital on 20 August 2025 with symptoms of high fever, bloody diarrhoea, haemorrhage and extreme weakness. She died on 25 August 2025 from multiple organ failure. Two health-care workers that had contact with this first case also developed similar symptoms and died. The WHO states that approximately 80% of the suspected cases are aged 15 years and older. In response to the outbreak, from the DRC MoH and WHO have arrived Bulape health zone and delivered the first batch of emergency health supplies. The WHO has shipped and equipment from its emergency preparedness and response hub in Nairobi, Kenya to the DRC. of frontline responders that may be deployed to the affected area has begun in Kinshasa. at the national level for deployment to Bulape and Mweka. suggests that this outbreak is likely a zoonotic spillover event and is not directly linked to the in Luebo (2007) and Mweka (2008 to 2009). The WHO assess the of this outbreak as high at the national level, moderate at the regional level and low at the global level. Imported cases of Ebola disease (EBOD) are very rare in the UK. Four confirmed cases of EBOD, and no deaths, have been previously reported in the UK. The last reported confirmed case of was in 2014 |
| Further information |
Ebola: overview, history, origins and transmission Ebola virus disease: clinical management and guidance Ebola and Marburg haemorrhagic fevers: outbreaks and case locations |
| Disease or pathogen | Severe fever with thrombocytopaenia syndrome |
|---|---|
| Location | Japan and South Korea |
| Reporting date | 2 to 3 September 2025 |
| Summary | On 3 September 2025, media reported that cases have been recorded in South Korea between 1 January and 31 August 2025. This compares to 89 SFTS cases reported during the same period in 2024. In Japan, between 1 January and 24 August 2025, have been reported. Kochi Prefecture reported the highest number of cases (14 cases). The number of SFTS cases reported in 2025 is higher than the number reported in 2024 (). No known SFTS cases have been reported in the UK. |
| Further information |
Severe fever with thrombocytopaenia syndrome (SFTS): epidemiology, outbreaks and guidance NaTHNaC country information page: and |
For more information on the background and methods used in this report, see Outbreaks under monitoring: background and methodology.