Research and analysis

Outbreaks under monitoring: week 30 (week ending 26 July 2026)

Updated 30 July 2026

The following signal relates to an ongoing outbreak, with data as of 29 July 2026

Disease or pathogen	Bundibugyo virus disease (BVD)
Location	Multi-country
Status	Update
Reporting date	15 May to 29 July 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 World Health Organization (WHO) Director-General determined that the outbreak constitutes a public health emergency of international concern. As of 27 July 2026 (in French), 3,360 confirmed cases and 1,487 confirmed deaths have been reported in the DRC. This is an increase of 887 confirmed cases and 488 deaths since the last Outbreaks under monitoring report. Among these, 272 confirmed cases and 174 confirmed deaths were identified through retrospective data reconciliation and may not represent new infections or deaths that occurred during the current reporting period. Confirmed cases have been reported in Ituri (2,988 cases), North Kivu (325 cases), Haut-Uele (39 cases), Tshopo (5 cases) and South Kivu (3 cases) provinces. On 16 July 2026, Uganda began a 42-day countdown to declaring their outbreak over, after health authorities discharged the last recovered patient. A total of 20 confirmed cases (including 2 deaths) have been reported in Uganda. The last case was reported on 21 June 2026. 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 Uganda due to cross-border transmission through imported cases and ongoing epidemiological links to the DRC, high for countries with land borders adjoining countries with documented Bundibugyo virus detection, and low for the remaining countries in the African region, and globally. As of 29 July 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 and Uganda

Epidemiological week 30, 20 to 26 July 2026

Disease or pathogen	Crimean-Congo haemorrhagic fever (CCHF)
Location	Afghanistan and Iran
Status	Update
Reporting date	1 June to 24 July 2026
Summary	In June 2026, 483 new suspected cases of CCHF and 21 associated deaths were reported in Afghanistan. This represents a 174% increase in cases compared to May 2026 (176 cases and 9 deaths). This brings the total number of cases reported in Afghanistan in 2026 to 956 cases and 46 deaths. On 24 July 2026, media reported (in Persian) 49 confirmed cases of CCHF, including 5 deaths, in Iran in 2026. Cases have been reported across Hormozgan, Fars, Kerman, and Isfahan provinces. Health authorities have identified livestock owners, veterinarians, slaughterhouse staff, and medical staff as high-risk groups. Human cases of CCHF are reported annually in Iran. 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 Iran.

Disease or pathogen	Dengue
Location	Sri Lanka
Status	New
Reporting date	26 July 2026
Summary	As of 26 July 2026, Sri Lanka’s National Dengue Control Unit has reported 82,011 dengue cases and 61 deaths in 2026. The highest number of cases have been recorded in Gampaha (17,395) followed by Colombo (16,294 cases). In comparison, in 2025, up to 19 July, 32,318 dengue cases and 29 deaths were reported in Sri Lanka. The increase in cases observed in 2026 has been largely driven by elevated rainfall and flooding associated with the ongoing southwest monsoon season, which have created favourable breeding conditions for mosquito vectors. There is currently no evidence of local dengue transmission in the UK, or of established populations of the mosquito that transmit the virus. Cases reported in the UK have been related to travel abroad.
Further information	Dengue fever: guidance, data and analysis Travel-associated infections reports HAIRS risk assessment: Dengue NaTHNaC country information page: Sri Lanka

Disease or pathogen	Plague
Location	Mongolia
Status	New
Reporting date	22 to 24 July 2026
Summary	On 22 July 2026, media reported a suspected plague case in Khovd, Mongolia. Follow-up media reports (in Mongolian) on 24 July 2026 stated that the case had been confirmed by laboratory testing. The individual is reported to have become infected following the consumption of marmot meat while visiting Ulaankhus soum, Bayan-Ulgii province. A total of 17 out of 21 provinces in Mongolia are considered at risk for bubonic plague. Plague is typically reported in Mongolia between July and October, with the high-risk period considered to be between August and September. 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: Mongolia