Research and analysis

Outbreaks under monitoring: week 20 (week ending 17 May 2026)

Updated 21 May 2026

The following relates to an ongoing outbreak, with data current to 19 May 2026

Disease or pathogen	Bundibugyo virus disease (BVD)
Location	Multi-country
Status	New
Reporting date	15 to 19 May 2026
Summary	On 5 May 2026, the World Health Organization (WHO) was notified of a high-mortality outbreak of unknown illness in Mongbwalu Health Zone, Ituri Province, Democratic Republic of the Congo (DRC). On 15 May 2026, the  National Institute of Biomedical Research Kinshasa confirmed the detection of Bundibugyo virus disease (BVD) in 8 out of 13 blood samples in patients from Rwampara Health Zone, Ituri Province. BVD is a form of Ebola disease, caused by the Bundibugyo virus. In response, on 15 May 2026 the DRC Ministry of Public Health, Hygiene and Social Welfare declared an Ebola disease outbreak in the DRC. Uganda’s Ministry of Health confirmed an outbreak of BVD on the same day, following the report of an imported case in Kampala from the DRC. On 16 May 2026, the WHO Director-General determined that the outbreak constitutes a public health emergency of international concern. By 19 May 2026, the number of cases reported had increased to over 500 suspected cases and 130 suspected deaths in the DRC, and 30 confirmed cases. Most suspected cases are aged between 20 and 39 years old, with females accounting for over 60% of cases. This suggests significant risks associated with household and caregiver transmission.   In addition, 2 confirmed cases, including one death, have been reported in Uganda amongst individuals who had travelled to the DRC. Furthermore, on 17 May the US Centers for Disease Control and Prevention reported that a confirmed case in an American national who had been occupationally exposed in the DRC, has been transferred to Germany for treatment. To control the spread of the outbreak, WHO have supported with the deployment of rapid response teams, the delivery of medical supplies and the strengthening of surveillance. Other response activities include infection prevention and control assessments, the set-up of safe treatment centres, and community engagement. This represents the 17th recorded outbreak of Ebola disease in the DRC since the virus was first identified in 1976, with the last reported outbreak ending in December 2025 in Kasai Province. Bundibugyo virus was first identified in 2007 in Bundibugyo district, western Uganda. A second outbreak caused by Bundibugyo virus was reported in DRC in 2012. As of 19 May, no imported cases associated with this outbreak have been reported in the UK. Previously in 2015, an imported case of Ebola virus disease was reported in the UK associated with the 2014 to 2016 West Africa outbreak. The risk of the current Ebola outbreak to the UK population is assessed as low.
Further information	Ebola: overview, history, origins and transmission Ebola virus disease: clinical management and guidance Ebola and Marburg haemorrhagic fevers: outbreaks and case locations UKHSA blog:  What is Ebola and how does it spread? NaTHNaC country information page: Democratic Republic of the Congo and Uganda

Disease or pathogen	Andes virus
Location	Multi-country
Status	Update
Reporting date	19 May 2026
Summary	On 2 May 2026, WHO was notified of a cluster of severe respiratory illness aboard a cruise ship carrying 147 passengers and crew from various countries. The cruise ship departed from Ushuaia, Argentina, on 1 April 2026, and travelled across the South Atlantic. On 2 May 2026, laboratory testing of samples taken from a case confirmed hantavirus infection. Further testing of samples from cases confirmed Andes virus infection. As of 19 May 2026, 11 cases (9 confirmed and 2 probable), including 3 deaths (2 confirmed and one probable) have been reported. The latest confirmed case was reported from Canada in an individual who had been a passenger of the cruise ship. Furthermore, additional testing of a previously reported inconclusive case in the US has confirmed that the individual was negative for Andes virus. WHO currently assesses the risk of this event to the global population to be low. There is very low risk of hantavirus in the UK. Seoul hantavirus is the only species to have been identified in the UK and does not spread between people. It is possible that rare, travel-associated Andes virus infections may be seen in the UK in individuals returning from where Andes virus is considered endemic, although none have been reported to date.
Further information	Andes hantavirus: epidemiology, outbreaks and guidance Hantaviruses: characteristics, diagnosis and epidemiology HAIRS risk assessment: hantavirus UKHSA blog: What is hantavirus? How is it transmitted and what are the symptoms? NaTHNaC Hantavirus and Hantavirus cruise ship outbreak NaTHNaC country information page: Argentina, Chile and Uruguay

Epidemiological week 20, 11 to 17 May 2026

Disease or pathogen	Crimean-Congo haemorrhagic fever (CCHF)
Location	Afghanistan and Iraq
Status	Update
Reporting date	30 April to 13 May 2026
Summary	During April 2026, 152 suspected CCHF cases and 6 deaths (case fatality rate of 3.9%) were reported in Afghanistan. This represents a 141.3% increase in cases compared to March 2026 (63 cases and 5 deaths), and brings the total number of cases reported in 2026 to 296 cases. On 13 May 2026, media (in Arabic) reported 48 confirmed human cases of CCHF and 4 deaths in Iraq, since the beginning of 2026. The highest number of cases have been reported in Dhi Qar governorate (21 cases and 3 deaths). According to the article, cases have been associated with livestock farming. Afghanistan and Iraq report cases of CCHF annually. CCHF is not present in the UK, nor are there any identified established populations of Hyalomma ticks, the principal vectors of CCHF virus. Confirmed CCHF cases have been imported into the UK, including one fatal case in 2012 and one in 2014.
Further information	Crimean-Congo haemorrhagic fever: origins, reservoirs, transmission and guidelines HAIRS risk assessment: Crimean-Congo haemorrhagic fever NaTHNaC country information page: Afghanistan and Iraq