Research and analysis

Outbreaks under monitoring: week 17 (week ending 26 April 2026)

Updated 30 April 2026

Disease or pathogen	Avian influenza A(H5N1)
Location	Cambodia
Status	Update
Reporting date	22 April 2026
Summary	On 22 April 2026, the Cambodian Ministry of Health (on Facebook: in Khmer)  reported a human case of avian influenza A(H5N1) from Romduol district, Svay Rieng province in a 66-year-old woman. This is the fourth avian influenza A(H5N1) case reported in Cambodia in 2026. Investigations found that sick and dead poultry around the case’s home had been used for cooking. The case has been isolated in hospital.  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	Severe fever with thrombocytopaenia syndrome (SFTS)
Location	South Korea
Status	New
Reporting date	21 April 2026
Summary	On 21 April 2026, South Korea’s Disease Control and Prevention Agency (in Korean) reported a confirmed case of SFTS in Ulsan Metropolitan City in an individual aged in their 70s. The case presented to a healthcare setting with compatible symptoms after farming in a vegetable garden. Exposure to ticks through gardening and agricultural activities is a known risk factors for infection. This is the first SFTS case reported in South Korea in 2026. During 2025, 280 cases were reported across South Korea, representing the highest annual number of reported cases in over a decade. The SFTS virus is not found in the UK, and no travel-associated cases have been reported in the UK to date.
Further information	Severe fever with thrombocytopaenia syndrome (SFTS): epidemiology, outbreaks and guidance. NaTHNaC country information page: South Korea

Disease or pathogen	Crimean-Congo Haemorrhagic fever (CCHF)
Location	Pakistan
Status	Update
Reporting date	23 April 2026
Summary	On 23 April 2026, media reported a fatal human case of CCHF in Sindh province, Pakistan. The case was a 17 year old male who worked at a cattle farm in Tando Adam. Pakistan reports cases of CCHF annually. During 2025, 82 cases, including 20 deaths, were reported. 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: Pakistan

Disease or pathogen	Mpox
Location	Pakistan and Poland
Status	New
Reporting date	21 to 24 April 2026
Summary	On 24 April 2026, the World Health Organization (WHO) published information on the first case of clade I mpox in Poland, reported on 13 April 2026. The individual is an adult male with travel history to Slovakia. No onward transmission has been reported in association with this case. This case represents the first report of clade I mpox exposure in Slovakia. On 2 April 2026, media reported paediatric cases with symptoms compatible with mpox across healthcare facilities in Sindh province, Pakistan. On 4 April 2026, further media sources reported that 7 newborn babies in Khairpur district tested positive for mpox, including 4 fatalities among babies with pre-existing complications including low birth weight, premature birth and malnutrition. Further testing identified clade Ib mpox in Sindh and Southern Punjab, according to media on 21 April 2026. In 2026, up to 14 April, 122 mpox cases, including 25 confirmed cases and 9 deaths have been reported in Sindh province. In the UK, cases of clade Ib and IIb mpox continue to be reported. Up to 31 March 2026, 45 clade Ib mpox cases have been reported, most of which have direct or indirect travel links to countries where clade Ib mpox is circulating.
Further information	Mpox: guidance Mpox clade Ib and clade IIb outbreak: epidemiological overview NaTHNaC country information page: Pakistan, Poland and Slovakia.