Research and analysis

Outbreaks under monitoring: week 11 (week ending 15 March 2026)

Updated 19 March 2026

Disease or pathogen	West Nile virus
Location	Anguilla
Status	New
Reporting date	11 March 2026
Summary	On 11 March 2026, Anguilla’s Ministry of Health, Tourism and Sports reported the territory’s first-ever locally-acquired human case of West Nile virus (WNV). The case reported no recent travel history and experienced symptom onset on 7 March 2026. The case was later hospitalised and laboratory testing on 10 March 2026 confirmed WNV infection by polymerase chain reaction. According to the report, the detection of a WNV case is not unexpected as the virus has been detected in mosquitoes, birds and horses across the Caribbean territory since the early 2000s. No known locally-acquired human WNV cases have been reported in the UK. However, there is an existing risk to UK residents who travel to endemic areas abroad. Between 2000 and June 2025, 7 confirmed WNV cases were recorded in UK residents, all acquired through travel. The probability of human infection with WNV in the general UK population is currently considered, at most, very low. For higher risk groups including individuals living, working or visiting areas with active human-biting mosquito vectors co-located with infected birds, the probability of infection would be considered low.
Further information	HAIRS risk assessment: West Nile virus West Nile virus: epidemiology, diagnosis and prevention Surveillance and updates for West Nile virus infection NaTHNaC country information page: Anguilla

Disease or pathogen	Avian influenza A(H5N1)
Location	Cambodia
Status	Update
Reporting date	15 March 2026
Summary	On 15 March 2026, the Cambodian Ministry of Health (in Khmer) reported a human case of avian influenza A(H5N1) from Ropai village, Banteay Meanchey province. This is the second avian influenza A(H5N1) case reported in Cambodia in 2026. Investigations found that the case had been raising poultry at home, some of which had been sick and died. Other poultry deaths were recently reported in the village where the case resides. The case was hospitalised and treated with oseltamivir (Tamiflu). Oseltamivir was given to close contacts of the case as post-exposure prophylaxis. Investigations and response by Cambodia’s cross-government health agencies are ongoing and include active case finding, contact tracing and source investigation in humans and animals. 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