Research and analysis

Outbreaks under monitoring: week 45 (week ending 9 November 2025)

Updated 13 November 2025

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), the USA and Malaysia. Some of the new clade Ib cases in European countries (Belgium, Greece, the Netherlands and Spain) and the USA are among gay, bisexual, and other men who have sex with men (GBMSM);  marking the first reported detections of clade Ib mpox in GBMSM sexual networks. Between October 2024 and 31 October 2025, 18 clade Ib mpox cases were reported in the United Kingdom. Most of the cases had direct or indirect travel links to countries where clade Ib mpox is circulating. UKHSA published a technical assessment on 27 October 2025. The risk of future imports of clade Ib mpox is considered high, given community transmission in several countries with strong travel links to the UK. The risk of onwards transmission is considered low to medium, with some uncertainty, but owing in part to high vaccination uptake in GBMSM.
Further information	Mpox: guidance Mpox clade Ib and clade IIb outbreak: UK epidemiological overview Mpox: technical assessment NaTHNaC country information page: Belgium, 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 9 November 2025
Summary	On 26 September 2025, Senegal’s Ministry of Health and Public Hygiene reported an outbreak [Facebook login required] of Rift Valley fever (RVF) in the Saint-Louis region. As of 8 November 2025, 416 RVF cases [Facebook] including 30 deaths have been reported. Most cases have been reported in Saint-Louis region (318 cases). This is an increase of 35 cases and one death since the last report [Facebook]. 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). Between 1 January and 30 October 2025, 46 confirmed cases, including 14 deaths, have been reported across 13 regions of Mauritania. This is an increase of 4 confirmed cases since the last report with data up to 24 October 2025 [PDF]. The WHO currently assesses the overall risk of RVF outbreaks in Mauritania and Senegal as high at the national levels, moderate at the regional level and low at the global level. 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