Research and analysis

Outbreaks under monitoring: week 44 (week ending 2 November 2025)

Updated 13 November 2025

Disease or pathogen	Chikungunya
Location	France
Status	Situation update
Reporting date	22 to 29 October 2025
Summary	In France, 762 locally acquired cases of chikungunya [in French] have been reported between 1 May and 27 October 2025. This is an increase of 13 cases since the last report on 22 October 2025 [in French]. The number of locally acquired cases recorded in 2025 is the highest since 2010. For the first time ever, locally acquired cases were reported in the departments of Grand Est, Bourgogne-Franche-Comte, Centre-Val de Loire and Nouvelle-Aquitaine. The World Health Organization (WHO) states that the increased incidence in 2025 is linked to the chikungunya outbreak in Reunion and the broader Indian Ocean region. In the 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    NaTHNaC country information page: France

Disease or pathogen	Mpox (clade I)
Location	Multi-region
Status	Situation update
Reporting date	20 to 31 October 2025
Summary	In October 2025, community transmission of clade Ib mpox was reported for the first time in several European countries (Italy, the Netherlands, Portugal and Spain [in Spanish]), the USA and Malaysia. Some of the new cases in these countries (USA (3 cases), Spain (1 case) and the Netherlands (1 case)) have been among gay, bisexual, and other men who have sex with men (GBMSM), and mark the first reported detections of clade Ib mpox in GBMSM. On 31 October 2025, the European Centre for Disease Prevention and Control reported the first case of clade I mpox in Greece. The imported case was in a man who had reported sexual contact with another man. In the UK, clade Ib and clade IIb mpox cases have been officially reported. As of 16 October 2025, 16 clade Ib mpox cases have been reported, all in England. The last reported UK case was in August 2025. Most of the cases have direct or indirect travel links to countries where clade Ib mpox is circulating.
Further information	Mpox: guidance Mpox clade Ib and clade IIb outbreak: UK epidemiological overview Mpox: technical assessment NaTHNaC country information page: Greece, Italy, Malaysia, Netherlands, Portugal, Spain,  United States,

Disease or pathogen	Rift Valley fever
Location	Mauritania and Senegal
Status	Situation update
Reporting date	26 September to 2 November 2025
Summary	On 26 September 2025, Senegal’s Ministry of Health and Public Hygiene reported an outbreak of Rift Valley fever (RVF) in the Saint-Louis region [Facebok login required] . As of 1 November 2025, 381 RVF cases [Facebook] including 25 deaths, have been reported. Most cases have been reported in Saint-Louis region (294 cases). This is an increase of 57 cases and 4 deaths since the last report [Facebook]. The Africa CDC [PDF] has stated that males account for 64% of confirmed cases. Between 1 January and 27 October 2025, 176 RVF cases (42 confirmed) and 14 deaths [PDF]  have been reported across 11 regions of Mauritania. This is an increase of 70 confirmed cases and one death since the last report with data valid up to 17 October 2025 [PDF]. Genomic analysis suggests that the current RVF outbreak in Senegal is directly linked to the previous detections in Senegal (Fatick in 2020 and Matam in 2022) and Mauritania (2020). No known human RVF cases have been reported in the UK.
Further information	Viral haemorrhagic fevers: origins, reservoirs, transmission and guidelines NaTHNaC country information page: Mauritania and Senegal