Research and analysis

Outbreaks under monitoring: week 19 (week ending 10 May 2026)

Updated 14 May 2026

The following relates to an ongoing outbreak, with data current to 11 May 2026

Disease or pathogen	Andes virus
Location	Multi-country
Status	Update
Reporting date	2 to 11 May 2026
Summary	On 2 May 2026, the World Health Organization (WHO) was notified of a cluster of severe respiratory illness aboard a cruise ship carrying 147 passengers and crew from various countries. The cruise ship departed from Ushuaia, Argentina, on 1 April 2026, and travelled across the South Atlantic. On 2 May 2026, laboratory testing of samples taken from a case confirmed hantavirus infection. Further testing of samples from cases confirmed Andes virus infection. As of 8 May 2026, 8 cases (6 confirmed and 2 probable), including 3 deaths (2 confirmed and 1 probable) have been reported. In addition to these cases, on 11 May 2026, Spain’s Minister of Health (in Spanish) reported a provisionally polymerase chain reaction (PCR)-positive case in a passenger that had been repatriated from the MV Hondius cruise ship to Madrid. The passenger has been isolated and is asymptomatic. The European Centre for Disease Prevention and Control also reported a confirmed case in a repatriated passenger who developed symptoms during a flight to France. The case is hospitalised in intensive care. Furthermore, the United States Department of Health and Human Services reported the detection of a PCR-positive repatriated passenger in addition to a symptomatic passenger. According to WHO, the outbreak is being managed through a coordinated international response, including the organisation of epidemiological investigations, case isolation and care, and medical evacuation. In response, WHO currently assesses the risk of this event to the global population to be low. There is very low risk of hantavirus in the UK. Seoul hantavirus is the only strain to be identified in the UK and does not spread between people. It is possible that rare, travel-associated Andes virus infections may be seen in the UK in individuals returning from where Andes virus is considered endemic, although none have been reported to date. Human-to-human transmission is also known to be rare, although possible.
Further information	Andes hantavirus: epidemiology, outbreaks and guidance Hantaviruses: characteristics, diagnosis and epidemiology HAIRS risk assessment: hantavirus NaTHNaC Hantavirus and Hantavirus cruise ship outbreak NaTHNaC country information page: Argentina, Chile and Uruguay

Epidemiological week 19, 4 to 10 May 2026

Disease or pathogen	Avian influenza A(H5N6)
Location	China
Status	New
Reporting date	8 May 2026
Summary	Between 1 and 7 May 2026, the WHO) reported 1 new human case of avian influenza A(H5N6) infection in Chongqing Municipality, China. The case was a 55 year old female who experienced symptom onset on 16 April 2026 and later developed severe pneumonia. She was hospitalised on 23 April 2026 and died on 3 May 2026. Epidemiological investigations found that the case had purchased, slaughtered and consumed poultry. Environmental sampling detected avian influenza A(H5) on the cutting board used for preparation. All close contacts tested negative for avian influenza A(H5N6). Since 2014, up to 7 May 2026, 93 confirmed human cases of avian influenza A(H5N6), including 58 deaths, have been reported in the WHO Western Pacific Region.
Further information	Avian influenza: guidance, data and analysis Avian influenza A(H5N6): risk assessment NaTHNaC country information page: China

Disease or pathogen	Crimean-Congo haemorrhagic fever (CCHF)
Location	Kazakhstan and Turkey
Status	New
Reporting date	7 to 8 May 2026
Summary	On 7 May 2026, media reported a fatal human case of CCHF in Zhambyl Region, Kazakhstan. The case managed a livestock farm in Shu district and was reportedly exposed through a tick bite. On 8 May 2026, media (in Turkish) reported a fatal human case of CCHF in Turkey. The case had visited Daday district in Kastamonu where they were bitten by a tick. After seeking medical attention, the case was hospitalised and moved to the intensive care unit in Istanbul, where they died. Kazakhstan and Turkey report cases of CCHF annually. 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 1 fatal case in 2012 and 1 in 2014.
Further information	Crimean-Congo haemorrhagic fever: origins, reservoirs, transmission and guidelines HAIRS risk assessment: Crimean-Congo haemorrhagic fever NaTHNaC country information page: Kazakhstan and Turkey

Disease or pathogen	Swine influenza A(H1N2)v
Location	United States
Status	New
Reporting date	8 May 2026
Summary	On 8 May 2026, the United States Centers for Disease Prevention and Control reported a human case of influenza A(H1N2)v virus in Nebraska. The case, who is under 18 years old, experienced symptom onset during the week ending 4 April 2026 and sought medical care during the week ending 18 April 2025 due to worsening symptoms. The case was not hospitalised and has recovered. Investigations did not identify any direct or indirect swine contact. A close contact of the case became mildly symptomatic on the same day as the case. No additional cases of infection with A(H1N2)v associated with this case have been identified. This case represents the second human detection of influenza A(H1N2)v infection in the United States during the 2025 to 2026 season.
Further information	Influenza A(H1N2)v: guidance for affected members of the public Influenza (avian and other zoonotic) NaTHNaC country information page: United States