Research and analysis

Outbreaks under monitoring: week 40 (week ending 4 October 2026)

Updated 8 October 2026

The following signal relates to an ongoing outbreak, with data as of 6 October 2026

Disease or pathogen	Bundibugyo virus disease (BVD)
Location	Multi-country
Status	Update
Reporting date	15 May to 6 October 2026
Summary	On 15 May 2026, an outbreak of Ebola disease caused by Bundibugyo virus was declared in the Democratic Republic of the Congo (DRC) and Uganda. On 17 May 2026, the WHO Director-General determined that the outbreak constitutes a public health emergency of international concern. The outbreak in DRC remains a public health emergency of international concern as of the latest WHO Emergency Committee meeting, held on 18 August 2026. As of 4 October 2026, 8,603 confirmed cases and 4,148 confirmed deaths have been reported in the DRC. This is an increase of 487 confirmed cases and 224 deaths since the last Outbreaks Under Monitoring report. Cases have been reported in 64 health zones across 7 provinces (Ituri, North Kivu, South Kivu, South-Ubangi, Haut-Uele, Bas-Uele and Tshopo). Although most cases have been reported in Ituri (6,450 cases, including 2,968 deaths), an increase in the number of new cases has been reported in North Kivu (1,729 cases, including 1,005 deaths). This has become the largest recorded BVD outbreak and is the second largest Ebola disease outbreak to date. On 1 October 2026, Medecins Sans Frontieres confirmed one staff member working in the DRC tested positive for BVD. The case was medically evacuated to Leiden, Netherlands and is being treated at Leiden University Medical Center (in Dutch). This is the fourth BVD case imported into Europe that is linked to the current outbreak in the DRC. All of the imported cases had been working on the response to the Ebola outbreak. The other cases were: 2 US nationals who were medically evacuated to Germany, and a humanitarian worker who was isolated immediately on their return to France (in French). On 6 October 2026, Kenya’s Ministry of Health reported the first confirmed case of BVD in Kenya, imported from the DRC. The case presented with symptoms a month ago and received treatment from several hospitals in the DRC. The case travelled from the DRC to Kampala, Uganda, by road and arrived in Nairobi via a flight on 3 October 2026. Samples from the case tested positive for Ebola Bundibugyo virus. The case was given supportive treatment but died on 5 October 2026. 28 contacts of the case, including family members and health workers, have been identified. The Ministry of Health is also tracing a further 23 passengers and 4 crew from the flight from Kampala to Nairobi. On 27 August 2026, WHO and the Africa Centres for Disease Control and Prevention declared the end of the outbreak in Uganda following no new cases since the last case was discharged from care on 16 July 2026. A total of 20 confirmed cases (including 2 deaths) were reported in Uganda. Of the confirmed cases, 15 were imported from the DRC and five were secondary cases among contacts. This is the 17th recorded Ebola disease outbreak in the DRC since the virus was first identified in 1976. The last reported outbreak, in Kasai Province, ended in December 2025. 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. WHO continues to assess the risk of this event as very high in the DRC, high for countries with land borders adjoining the DRC, and low for the remaining countries in the African region, and globally. As of 6 October 2026, no imported cases associated with this outbreak have been reported in the UK. Previous experience from the 2014 to 2016 West Africa outbreak suggests a limited importation risk, with only one travel-related case reaching the UK outside of medical evacuations. The risk of the current 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, Uganda, and Kenya.

Epidemiological week 40, 28 September to 4 October 2026

Disease or pathogen	Avian influenza A(H5N1)
Location	Cambodia
Status	Update
Reporting date	28 September 2026
Summary	On 28 September 2026, the Cambodian Ministry of Health (in Khmer) reported a human case of avian influenza A(H5N1) from Trapeang Prasat district, Oddar Meanchey province in a 49-year-old poultry farmer. Investigations found that the case had direct contact with sick and dead poultry which had also tested positive for avian influenza A(H5N1). The case has been isolated in hospital and is receiving treatment. This is the sixth avian influenza A(H5N1) case reported in Cambodia in 2026. Response activities by Cambodia’s cross-government health agencies include active case finding, contact tracing, and source investigation in both humans and animals. Oseltamivir has been offered to close contacts. In 2025, Cambodia reported 18 confirmed avian influenza A(H5N1) human cases, including 9 deaths.
Further information	Avian influenza: managing human exposures to incidents in birds or animals NaTHNaC country information page: Cambodia

Disease or pathogen	Suspected plague (pneumonic)
Location	Russia
Status	New
Reporting date	2 October 2026
Summary	On 2 October 2026, media reported a suspected fatal case of pneumonic plague case in Irkutsk region, Russia. The case, a 28-year-old who reportedly worked at the Irkutsk Anti-Plague Research Institute of Siberia and Far East, was hospitalised on 29 September 2026 in Shelekov, Irkutsk with severe pneumonia, and died on 1 October 2026. Media have widely reported that the case had pneumonic plague, but at this stage, this has not been officially confirmed. Rospotrebnadzor, the Federal Service for the Oversight of Consumer Protection and Welfare (the national public health agency of Russia), has so far stated the diagnosis as “pneumonia of unknown etiology”, according to media on 4 October 2026 (in Russian). In response, media have reported that hospitals in the area including the regional hospital where the case was admitted has been closed for quarantine, and epidemiological investigations have identified no symptomatic contacts, although nearly 200 individuals remain under observation. Plague is not found in the UK. The probability of a case occurring in a person returning to the UK is considered very low.
Further information	Plague: epidemiology, outbreaks and guidance Plague: interim guidance for clinicians NaTHNaC country information page: Russia

Disease or pathogen	Sindbis virus
Location	Germany
Status	New
Reporting date	1 October 2026
Summary	According to Germany’s Robert Koch Institut (in German), in September 2026, a locally acquired case of Sindbis virus infection was detected in Baden-Wurttemberg, Germany. The case was a 60 year old male who experienced symptom onset on 12 July 2026, including fever, rash and arthralgia. The case had no travel history outside of Baden-Wurttemberg and no link to an imported exposure. This is the first confirmed symptomatic autochthonous Sindbis virus infection in Germany. The district the case lives in has established populations of Aedes albopictus. In Germany, Sindbis virus was first detected in mosquitoes in 2009, birds in 2014, and between January 2010 to February 2016, was detected in 4 healthy blood donors from Weinheim (an area where the virus had been previously detected in mosquitoes).
Further information	ECDC: Facts about Sindbis fever UKHSA: Enhanced surveillance to assess the presence of Sindbis and Batai virus in mosquito populations at an urban zoo in the United Kingdom. NaTHNaC country information page: Germany