Key facts
- On 15 October 2026, a confirmed human case of avian influenza A(H5N1) was reported in a resident of Yakima County, Washington state, USA, following occupational exposure to infected dairy cattle at a local dairy farm.
- The case had mild symptoms and was not hospitalised.
- Since 1 April 2024, and as of 15 October 2026, 72 human cases with avian influenza have been reported from 13 states in the United States (US). Of these, 42 were individuals exposed to dairy cattle known or presumed to be infected with A(H5N1) and 24 were workers exposed to outbreaks of HPAI A(H5) at poultry farms. Three people had no known animal exposure and three had exposure to other animals, such as backyard flocks, wild birds, or other mammals.
- According to the US CDC, the risk from A(H5N1) viruses to the general population remains low, while the risk to individuals in contact with potentially infected animals, contaminated surfaces or fluids is considered moderate to high.
- ECDC is closely following the situation and is in close contact with
Overview
Update:
On 15 October 2026, a confirmed human case of avian influenza A(H5N1) was reported in a resident of Yakima County, Washington state, USA, following occupational exposure to infected dairy cattle at a local dairy farm (press release). The case experienced mild illness, was not hospitalised, and is currently isolating at home. Public health authorities have initiated contact tracing and symptom monitoring of close contacts to assess any potential onward transmission. No evidence of sustained human-to-human transmission has been identified.
Since the detection of highly pathogenic avian influenza (HPAI) A(H5N1) in dairy cattle in Yakima County, local health authorities have been working with affected dairy farms to reduce the risk of human exposure. Measures include provision of guidance, testing of symptomatic exposed individuals, and facilitation of access to personal protective equipment (PPE) for dairy workers.
The US authorities emphasise that the risk of infection for the general public remains low, while individuals with close or prolonged exposure to infected animals or contaminated environments are at increased risk. Human-to-human transmission of influenza A(H5N1) virus remains rare.
Background:
Since 1 April 2024, and as of 19 October 2026 (access date 19 October 2026), 72 human cases of avian influenza A(H5N1), including one death, have been confirmed by the US CDC from 13 states. In total, 42 cases reported exposure to dairy cattle in the following states: California (36), Colorado (1), Michigan (2), Nevada (1), Texas (1), and Washington (1) and 24 cases reported exposure to poultry farms and culling operations in the following states: Colorado (9), Iowa (1), Ohio (1), Oregon (1), Washington (11), and Wisconsin (1). Three cases reported exposure to other animals, such as backyard flocks, wild birds, or other mammals: one case in Louisiana, who later died, one in Wyoming, and one in Washington. Three additional cases with unknown exposure have also been identified: two in California and one in Missouri.
On 19 March 2025, US CDC published findings from two laboratory investigations related to previously reported human cases of avian influenza A(H5N1) virus infections.
ECDC assessment
To date, there have been no confirmed human cases of influenza A(H5N1) infection and no reports of A(H5N1) infection in cattle in the EU/EEA. The genotype B3.13, identified in cattle and several of the human cases in the US, has not been detected in Europe. The genotype D1.1 has been found in wild birds, poultry, a limited number of cattle herds in the US, and a small number of human cases in the US and Canada. The genotype D1.3 has been identified in one human case in Ohio.
ECDC has assessed the risk from the circulating HPAI A(H5N1) clade 2.3.4.4b viruses as low for the general population and low-to-moderate for those whose activities expose them to infected animals or contaminated environments (e.g. occupational exposure to infected animals).
Actions
ECDC is monitoring the situation together with partner organisations in Europe and will continue to update its assessment of the risk for humans in the EU/EEA as new information becomes available.
In addition to enhanced surveillance, active monitoring and testing of exposed individuals is recommended for early detection of human cases and to assess the possibility of human-to-human transmission, according to relevant ECDC guidance documents ('Testing and detection of zoonotic influenza virus infections in humans'; 'Investigation protocol of human cases of avian influenza virus'; 'Enhanced surveillance of severe avian influenza virus infections in hospital settings').
It is important to raise awareness, including among all primary care workers, of the need to enquire about animal exposure and symptoms compatible with avian influenza infections and to test symptomatic individuals with a history of exposure, following a risk-based approach. It is also important to communicate the epidemiological situation so as not to miss or delay diagnosis of potential human cases.
Given the uncertainties related to mammal-to-mammal transmission and depending on the epidemiological situation, a low threshold can be considered for testing individuals exposed to potentially infected mammals (e.g. symptomatic individuals with conjunctivitis or respiratory symptoms). Due to the higher risk of infection for individuals exposed to infected animals and contaminated environments, appropriate personal protective measures and other precautionary measures should always be taken to mitigate the risk.
Relevant ECDC publications:
- Testing and detection of zoonotic influenza virus infections in humans in the EU/EEA, and occupational safety and health measures for those exposed at work
- Investigation protocol of human cases of avian influenza virus infections in the EU/EEA
- Surveillance and targeted testing for the early detection of zoonotic influenza in humans during the winter period in the EU/EEA
- Joint ECDC-EFSA Drivers for a pandemic due to avian influenza and options for One Health mitigation measures
- Coordinated One Health investigation and management of outbreaks in humans and animals caused by zoonotic avian influenza viruses
- Preparedness, prevention and control related to zoonotic avian influenza
ECDC is in contact with the US CDC for further information and is closely following any updates on the event. ECDC monitors zoonotic avian influenza strains through its influenza surveillance programme and epidemic intelligence activities in collaboration with the European Food Safety Authority (EFSA) and the EU Reference Laboratory for Avian Influenza in order to identify significant changes in the virological characteristics and epidemiology of the virus. Together with EFSA and the EU Reference Laboratory for Avian Influenza, ECDC produces a quarterly updated report on the avian influenza situation.