Research and analysis

Outbreaks under monitoring: week 42 (week ending 16 October 2026)

Updated 22 October 2026

The following signal relates to an ongoing outbreak, with data as of 20 October 2026

Disease or pathogen	Bundibugyo virus disease (BVD)
Location	Multi-country
Status	Update
Reporting date	15 May to 20 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 18 October 2026, 9,552 confirmed cases and 4,602 confirmed deaths have been reported in the DRC. This is an increase of 468 confirmed cases and 221 deaths since the last Outbreaks Under Monitoring report. Cases have been reported in 66 health zones across 8 provinces (Ituri, North Kivu, South Kivu, South-Ubangi, North-Ubangi, Haut-Uele, Bas-Uele and Tshopo). The latest affected area is Wapinda health zone, North-Ubangi province. This province sits on the border of the DRC and the Central African Republic, raising concerns for potential cross-border transmission. Although most cases have been reported in Ituri (6,960 cases, including 3,217 deaths), a general decrease in the number of newly reported cases in this province has been observed, while transmission has persisted in North Kivu (2,084 cases, including 1,176 deaths) and Haut-Uele (415 cases, including 177 deaths) provinces. Due to these heterogeneous transmission patterns across provinces, incidence remains high and fluctuating nationally. This has become the largest recorded BVD outbreak and is the second largest Ebola disease outbreak to date. On 6 October 2026, Kenya’s Ministry of Health reported the first confirmed case of BVD in Kenya, imported from 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. As of 20 October 2026, a total of 9 confirmed cases have been reported in Kenya. All cases are epidemiologically linked to the initial imported case and all were identified while in quarantine. According to Kenya’s MoH there is no evidence of transmission outside of this cluster. In response, supplies, including personal protective equipment and diagnostic kits have been distributed to 12 very high risk and 16 high risk counties. As of 20 October 2026, 134 contacts out of 135 listed contacts have been traced and quarantined. An additional, 5 contacts have been identified outside of Kenya. On 20 October 2026, Nigeria’s Centre for Disease Control reported the first confirmed case of BVD. The case was confirmed in Abuja, in a woman who had recently travelled from Uganda.  In response, the case has been isolated and is receiving medical treatment. As of 20 October 2026, 44 contacts have been identified for tracing and are being followed up. 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 5 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 20 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 42, 12 to 18 October 2026

Disease or pathogen	Argentine Haemorrhagic fever (AHF) (Junin virus)
Location	Argentina
Status	Update
Reporting date	15 October 2026
Summary	In 2026, up to 5 September, Argentina’s MoH (in Spanish) reported 276 cases of AHF, including 22 confirmed cases, nationally. The confirmed cases were reported in Cordoba (11 cases), Santa Fe (9 cases) and Buenos Aires (2 cases). This is a decrease in confirmed cases compared to the equivalent time period in 2025, when 50 cases were reported. AHF is endemic in Buenos Aires, Cordoba, Sante Fe and La Pampa provinces in Argentina. Most cases are reported during the harvest season in Argentina, which occurs between April and July. There have been no known cases of AHF reported in the UK to date.
Further information	Argentine Haemorrhagic fever: origins, reservoirs, transmission and guidelines Viral haemorrhagic fever: ACDP algorithm and guidance on management of patients NaTHNaC country information page: Argentina

Disease or pathogen	Avian influenza A(H5N1)
Location	United States
Status	New
Reporting date	15 October 2026
Summary	On 15 October 2026, the Yakima County Health District in Washington State, US, reported a confirmed human case of avian influenza A(H5N1) infection in an individual who had been exposed to infected dairy cattle. The case is isolating at home and did not experience severe illness or hospitalisation. In response, health authorities are contact tracing individuals who have been in close contact with the case to monitor them for symptoms. Health authorities assess the risk of avian influenza infection in the general public to be low but note that individuals with close or prolonged contact with infected animals or environments are at greater risk. According to the US Centers for Disease Control and Prevention, since 2024, 72 confirmed human cases of avian influenza A(H5) infection have been reported in the US. Of these, 42 cases reported exposure through the commercial agriculture and related operations for dairy cattle herds.
Further information	Avian influenza: managing human exposures to incidents in birds or animals NaTHNaC country information page: United States

Disease or pathogen	Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
Location	Saudi Arabia
Status	Update
Reporting date	15 October 2026
Summary	Between 1 January and 5 October 2026, 8 laboratory confirmed cases of MERS-CoV infection, including one death, were reported in Saudi Arabia, according to WHO. The cases were detected across 6 areas, including Al Jouf, Arar, Hafr Al-Batin, Riyadh (2 cases), Tabuk and Taif (2 cases). All the cases were symptomatic, most commonly presenting with fever, dyspnoea, and cough. 2 cases reported direct contact with camels while 6 cases reported no known camel exposure. No epidemiological links were identified between the cases, and no cases were identified among health and care workers. The cases appear to represent sporadic infections related to zoonotic spillover rather than a single outbreak cluster. As of 5 October 2026, WHO has been notified of 2,643 laboratory confirmed MERS cases globally, including 965 deaths, since the virus was first identified in 2012. The majority of cases (2,232 cases and 870 deaths) have been reported from Saudi Arabia. The UK has previously reported imported cases of MERS. 5 cases and 2 deaths were reported between 2012 and 2018. 3 of these cases were classed as imported cases and 2 cases were secondary cases in close family members.
Further information	MERS-CoV: clinical management and guidance NaTHNaC country information page: Saudi Arabia