Avian #Influenza #Report: October 25 - 31 '26 (Wk 44) (HK CHP, November 3, 2026): 2 New Human Infections with #H5N1 virus in #USA & 2 cases with #H9N2 virus in #China

 

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Avian influenza A(H5N1)

    ° Washington State:

        § The Washington State Department of Health reported the second and  third human infection with avian influenza A(H5N1) from Yakima County.

        § The second case, who had underlying health conditions, was  hospitalised with severe illness and passed away on November 1, 2026.

        § The third case has not experienced severe illness or been hospitalised.

        § Both cases had exposure to dairy cattle infected with avian influenza  A(H5N1) virus at local dairy farms.

(...)

Avian influenza A(H9N2):

    ° Hubei Province:

        § A two-year-old boy with onset on September 22, 2026.

    ° Jiangxi Province:

        § A 77-year-old woman with onset on September 16, 2026.

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Source: Centre for Health Protection, Hong Kong PRC SAR, https://www.chp.gov.hk/files/pdf/2026_avian_influenza_report_vol22_wk44.pdf

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#USA, #Washington State: Avian #Influenza in #Humans - Current #Situation and Data (DoH, Nov. 2 '26): 2 new cases of which 1 fatal [18 cases in total since 2024]

 

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Human Bird Flu Cases in Washington State Residents

[Case - Classification - Known Exposure - 2024 - 2025 - 2026 - Total]

    ° Confirmed - Commercial Poultry - 11* - 0- 0 - 11

    ° Confirmed - Backyard Flock - 0 - 1 - 0 - 1

    ° Confirmed - Dairy - 0 - 0 - 3 - 3 {+2}

    ° Probable - Commercial Poultry - 3 - 0 - 0 - 3

        § Total - 14 - 1 - 3 - 18

    {*} Washington residency not confirmed for one case in 2024.

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Source: US State of Washington Department of Health, https://doh.wa.gov/you-and-your-family/illness-and-disease-z/bird-flu/current-situation-and-data

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#USA, #Washington State: #Yakima County Resident Dies from Complications of Avian #Influenza { #H5N1 } (DoH, Nov. 2 '26): Third Human case also reported

     

For immediate release: November 1, 2026 | Contact: Stephanie Ruiz,  Communications Specialist (509) 941-7364 

Yakima County Resident Dies from Complications of Avian Influenza

    Yakima, WA - The Yakima County resident who was hospitalized with severe  illness after contracting avian influenza (bird flu) following exposure at a dairy with infected cattle died today.

    The Yakima Health District offers its heartfelt condolences to the  individual’s family, friends, and loved ones during this difficult time.

    The individual had underlying health conditions. Out of respect for the  family’s privacy, the Yakima Health District is not releasing their name, gender, or  age.

    The risk of avian influenza infection to the general public remains low. 

    People at greater risk include dairy workers and others who have close or  prolonged contact with infected animals or environments contaminated with the  virus. 

    Transmission of avian influenza between humans is extremely rare and  has never been documented in the United States. 

    Public health officials are continuing to monitor individuals who had  close contact with the patient for symptoms. 

Third Confirmed Human Case of Avian Influenza

    The Yakima Health District is reporting a third confirmed human case of  avian influenza in a Yakima County resident who was exposed to infected dairy cattle at a Yakima County dairy. 

    The individual has not experienced severe illness or been hospitalized.

    The Yakima Health District is working with public health partners to  identify and contact individuals who may have been in close contact with the  person to monitor for symptoms.

Ongoing Public Health Updates

    To keep the public informed, Yakima Health District plans to update its  avian influenza webpage every Monday and Thursday at 2:00pm with the latest  available information, including confirmed human case counts in Yakima County. 

    Updates will be shared as new information becomes available.

For the latest information, visit www.YakimaHealthDistrict.org/BirdFlu.

Quote

    “Our hearts go out to the individual's family and loved ones during this difficult  time. Avian influenza can cause severe illness, particularly among people who  have underlying health conditions. While this is a serious and heartbreaking  outcome, the risk to the general public remains low. We continue to work closely  with our public health partners to monitor the situation and protect the health of our community.” -Dr. Dave Atteberry, Health Officer, Yakima Health District

Source: US State of Washington, Yakima County Department of Health, https://www.yakimacounty.us/DocumentCenter/View/46819

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#H5N5 virus #transmission is driven by repeated cross-Atlantic introductions and transmission among high latitude #seabirds

 

Abstract

In November 2025, the first global H5N5 infection was reported in a person in Washington State. Previously, these viruses had only been detected in seabirds and shorebirds near the Atlantic Ocean, suggesting potentially distinct ecology from dominant H5N1 strains. Using 354 global H5N5 genomes, we show that H5N5 viruses have been carried by high latitude seabirds and shorebirds across the Atlantic at least 9 times, with introductions more frequent in the fall and spring. We reconstruct a plausible path of cross-continental movement via Arctic or sub-Arctic regions, followed by a year of cryptic circulation prior to human spillover. These data show that H5N5 viruses have undergone far more intercontinental movements than previously recognized, and exhibit host and geographic patterns that are fundamentally distinct from dominant H5N1 lineages. The distinct host ecology, geography, and movement, paired with the capacity to infect a person, suggest that enhanced surveillance may be warranted.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

National Institutes of Health, https://ror.org/01cwqze88, R01AI195533, 1F31AI202942-01, 75N93021C00016, U19AI181767

United States Department of Agriculture, SA-MZT-2023-065b

Source: BioRxIV, https://doi.org/10.64898/2026.10.29.762228

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#USA, #Washington State: Second #Yakima County Resident Tests Positive for Avian #Influenza (DoH, Nov. 1 '26): Patient is in serious condition

 

    Yakima, WA- The Yakima Health District (YHD), in coordination with the  Washington State Department of Health (DOH), is reporting a second human case  of avian influenza, also known as bird flu, in a Yakima County resident after  exposure at a dairy with infected cattle. 

    The individual is currently hospitalized with severe illness and has underlying health conditions.

    The risk of avian influenza infection to the general public remains low.  People at greater risk include dairy workers and others who have close or  prolonged contact with infected animals or environments contaminated with the  virus. 

    Transmission of avian influenza between humans is extremely rare and  has never been documented in the United States.

    The Yakima Health District is working with public health partners to  identify and contact individuals who may have been in close contact with the patient to monitor for symptoms. 

    YHD is also continuing to work with impacted dairies and public health  partners to identify people who may have been exposed to infected cattle, monitor  their health, and provide guidance and resources to help protect exposed  individuals. 

    This includes providing testing for exposed individuals who develop  symptoms to support prompt diagnosis and appropriate medical care.

Symptoms and When to Seek Guidance

    Symptoms of avian influenza in people can include eye redness or  irritation, fever or feeling feverish, cough, sore throat, runny or stuffy nose,  muscle or body aches, headache, and fatigue. 

Illness can range from mild to severe

    If you work on a dairy farm and develop symptoms after potential  exposure to infected cattle, contact your healthcare provider and let them know  about your exposure or the Yakima Health District at (509) 480-3770 for  guidance.

Updated Information on Avian Influenza in Dairy Cattle

    As of October 29, 33 dairy herds in Yakima County have tested positive  for highly pathogenic avian influenza (HPAI) H5N1. The Washington State  Department of Agriculture (WSDA) maintains updated information on confirmed  dairy herd detections through its website. The Yakima Health District will also  share public health updates and prevention guidance on its webpage: www.YakimaHealthDistrict.org/BirdFlu.

How to Reduce Your Risk

    The risk of avian influenza infection to the general public is low.  However, people who work with or have contact with potentially infected animals  are at higher risk and should follow workplace safety guidance and use  recommended personal protective equipment. 

    Residents should avoid touching sick or dead animals, animal waste, and  surfaces that may be contaminated. 

    Pasteurized milk and dairy products remain safe to consume.  Pasteurization inactivates avian influenza virus and other harmful pathogens.  

    People should avoid raw milk and unpasteurized dairy products because  they may contain harmful germs, including avian influenza. 

    Do not feed pets raw milk, unpasteurized dairy products, or raw meat,  including raw pet foods. 

    Cats are especially susceptible to avian influenza (H5N1), and exposure can  lead to severe illness or death. 

    Feeding cats raw milk or raw poultry can put them at risk of infection.

    It is especially important that people get a seasonal flu vaccine. While  the seasonal flu vaccine will not prevent bird flu infection, it reduces the risk of  becoming sick with both human and avian influenza viruses at the same time.  Seasonal flu vaccine is recommended for everyone six months and older. Talk to  your primary care provider to see if the flu vaccine is recommended for you.

About Avian Influenza

    Avian influenza, commonly called bird flu, is caused by Type A influenza  viruses that occur naturally in wild birds. The virus can spread from wild birds to  other animals, including poultry and mammals such as dairy cattle. It can also  spread to humans following close contact with infected animals or contaminated  environments. There is no evidence of human-to-human transmission at this time.

Reporting Sick or Dead Animals

Domestic Birds:

    • Report sick/dead domestic birds using the online form, or call the  Washington State Department of Agriculture’s Avian Health Program: 1-800-606- 3056. Visit Avian Influenza | Washington State Department of Agriculture for more  information about how to protect backyard flocks.

Wild Birds:

    • Use an online form to report sick/dead wild birds suspected of avian  influenza to the Washington Department of Fish & Wildlife.

Livestock

    • To report sick livestock, isolate affected animals and contact your  veterinarian and WSDA at 360-902-1878 or email ahealth@agr.wa.gov.

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    “The risk to the general public remains low, but we are taking this situation  seriously. We encourage dairy workers to answer calls and respond to text  messages from public health officials so we can check on their health, provide  guidance, and connect them with care if needed. Early communication helps us  support workers who may have been exposed.” - Dr. Dave Atteberry,  Health Officer, Yakima Health District

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Source: US State of Washington, Yakima County Department of Health, https://www.yakimacounty.us/DocumentCenter/View/46817

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Avian #Influenza #Report - October 11 - 17 '26 (Wk 42) (HK CHP, Oct. 20 '26): 1 New Human Case of #H5N1 Virus in the #US; 2 New #H9N2 Virus Cases in #China

 

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Avian influenza A(H5N1)

    ° {USA} Washington:

        § The patient is currently isolating at home and has not experienced severe illness or required hospitalisation.

        § The case had exposure to dairy cattle infected with avian influenza A(H5N1) virus at a local dairy farm.

        § The Washington state recorded their first detection of avian influenza  A(H5N1) in two dairy farms on October 8, 2026.

Avian influenza A(H9N2)

    °{China} Guizhou Province:

        § A four-year-old boy with onset on September 20, 2026.

    ° Henan Province:

        § A 68-year-old man with onset on September 17, 2026.

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Source: 

Link: https://www.chp.gov.hk/files/pdf/2026_avian_influenza_report_vol22_wk42.pdf

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#USA, #Washington State: Avian #Influenza - Current #Situation and Data (Dept. of Health, Oct. 16 '26): One New Human Case

 

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Current Situation

    There are several strains of bird flu that wild birds carry worldwide. The most widely circulating, or common, strain in the United States today is H5N1. This strain was first detected in the U.S. in wild birds in January 2022. 

    In Washington state, H5N1 was first identified in a backyard flock in May 2022. 

    H5N1 was first detected in dairy cattle in Washington in October 2026.

    H5N1 has since spread to domestic birds, including commercial poultry and backyard flocks, and to mammals, such as wild and domestic cats, and dairy cattle.

    The first human H5N1 case in Washington state was identified in October 2024 and was linked to close contact with birds and their environment during a commercial poultry outbreak. 

    In 2025, Washington also reported a human infection with H5N5, a strain not previously seen in humans. 

    Other subtypes that have infected humans are H6, H7, H9, and H10. CDC’s Avian Influenza Type A as more information on influenza virus subtypes.

Human Bird Flu Cases in Washington State Residents

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Source: 

Link: https://doh.wa.gov/you-and-your-family/illness-and-disease-z/bird-flu/current-situation-and-data

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#USA, #Washington State: #Yakima County Resident Tests Positive for Avian #Influenza { #H5N1 } (Dept. of Health, Oct. 16 '26)

 

{Excerpts}

    Yakima, WA- The Yakima Health District (YHD), in coordination with the  Washington State Department of Health (DOH), is reporting a confirmed case of  avian influenza in a Yakima County resident who was exposed to infected dairy cattle at a Yakima County dairy. 

    The resident has not experienced severe illness or been hospitalized. 

    The individual is isolating at home.

    The risk of avian influenza infection to the general public remains low. 

    People at greater risk include dairy workers and others who have close or  prolonged contact with infected animals or environments contaminated with the  virus. 

    Transmission of avian influenza between humans is extremely rare and has never been documented in the United States. 

    To ensure that human-to-human spread is not occurring, public health officials are contacting anyone who has been in close contact with the patient to monitor for symptoms.

    Since the initial detection of Highly Pathogenic Avian Influenza (HPAI) H5N1 in Yakima County, YHD has been in contact with the impacted dairies to  protect the health of people who may be exposed to infected cattle.

    YHD continues to coordinate with state and federal public health partners to  provide guidance and resources to help protect exposed individuals. This  includes providing tests for exposed individuals who develop symptoms to support  prompt diagnosis and appropriate medical care. 

    YHD is working with partners to connect affected dairies with appropriate  personal protective equipment (PPE) for their workers

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Source: 

Link: https://www.yakimacounty.us/2417/Media-Releases#docaccess-9da5cc1738194b3305738e318406f325

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#US State of #Washington health officials assisting with #hantavirus #investigations involving two different virus #strains in two separate events (Dept. of Health, May 16 '26)

 

Risk of hantavirus to the public remains very low

    OLYMPIA – The Washington State Department of Health (DOH) is working with local and federal partners on two separate hantavirus-related investigations. 

    One investigation involves individuals potentially exposed to cases linked to the MV Hondius cruise ship outbreak, while the other involves a hantavirus infection unrelated to the cruise ship. 

    The cases involve different virus strains and exposure circumstances and are not connected.

    Hantaviruses are a group of viruses carried by different rodent species. 

    Hantavirus pulmonary syndrome (HPS) is a rare but serious disease caused by exposure to infected rodents or their droppings, urine, or saliva. 

    About one out of three people diagnosed with HPS have died. 

    The risk of contracting any strain of hantavirus remains very low.

Investigation 1: Andes virus exposure monitoring in Washington

    Earlier this week, Public Health – Seattle & King County announced monitoring of three King County residents who were potentially exposed to the Andes strain of hantavirus linked to the MV Hondius cruise ship. 

    Two individuals were exposed during an international flight by a passenger who was later diagnosed with Andes virus, and one individual was exposed on the cruise ship. 

    All three people are currently asymptomatic. 

    Potentially exposed people are monitored for 42 days after their last exposure to a person infected with the Andes virus.

    Additionally, CDC has notified DOH of three additional Washington residents who were on the same international flight as two of the King County individuals and are considered to have low-risk exposures. 

    One individual is a King County resident. 

    The other two residents live in Eastern Washington. 

    DOH is not releasing further details to protect individual privacy. Out of an abundance of caution, local health jurisdictions are reaching out to these individuals to assess exposure and monitor them for symptoms.

    Andes virus is a type of hantavirus spread by rodents in South America. The rodents that carry the virus have not been found in the United States. In rare cases, Andes virus can spread from person to person, typically through prolonged, close contact with someone who is ill. No cases of Andes virus have been reported among Washington residents.

    Local health jurisdictions are in     regular contact with impacted residents to monitor for symptoms during the 42-day incubation period associated with Andes virus.

Investigation 2: Sin Nombre virus hantavirus pulmonary syndrome case in Chelan County

    Today Chelan-Douglas Health District reported the first case of Sin Nombre virus hantavirus in Washington state this year. This case is not connected to the MV Hondius cruise ship outbreak, which was caused by a different type of hantavirus.

    Sin Nombre virus-infected deer mice are found throughout Washington. Infected deer mice can spread the virus through urine, saliva, and droppings. People can become infected by breathing contaminated dust when disturbing rodent droppings, urine, nests, or nesting materials, particularly in enclosed or rodent-infested spaces. Less commonly, people can be infected by touching contaminated objects and touching their eyes, nose, or mouth, or by being bitten or scratched by an infected rodent.

    Any activity that puts you in contact with deer mouse droppings, urine, saliva, or nesting materials can place you at risk for infection. For information on how to safely clean areas where rodents may be present, DOH recommends the following guidance.

    DOH has tracked hantavirus cases since 1994. The state typically reports one to five Sin Nombre hantavirus cases each year. Unlike Andes virus, Sin Nombre virus does not spread from person to person.

    The risk to the public from any hantavirus is very low because: 

        - Sin Nombre virus infections can be prevented by avoiding contact with rodents and rodent-infested areas and using wet-cleaning methods when cleaning rodent droppings, dead or trapped rodents, or nesting materials.

        - Andes virus person-to-person transmission can be limited through early identification of cases and monitoring of close contacts.

    Visit DOH's website for additional information on Hantavirus.

    Our website is your source for a healthy dose of information. Get updates by following us on social media.

Source: 

Link: https://doh.wa.gov/newsroom/washington-health-officials-assisting-hantavirus-investigations-involving-two-different-virus

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#Fatal #Human Case of #Influenza #H5N5 in a Backyard Flock Owner — #Washington {State}, November 2025

 

Summary

-- What is already known about this topic?

- Since 2022, highly pathogenic avian influenza (HPAI) A(H5) viruses have circulated among wild birds in the United States. Seventy human cases of influenza A(H5), most with mild illness, have been reported in the United States since 2024; 14 human influenza A(H5N1) cases were previously identified in Washington.

-- What is added by this report?

- In November 2025, Washington reported the first human case of HPAI A(H5N5) infection worldwide. A positive laboratory result was obtained from a lower respiratory sample after multiple negative upper respiratory sample results; the patient experienced respiratory failure and died 28 days after symptom onset. The public health investigation identified approximately 135 exposed persons.

-- What are the implications for public health practice?

- Symptom management and testing of exposed persons are critical to monitoring for human-to-human transmission of novel influenza infection. Environmental and animal investigations, including genomic analysis, can identify epidemiologic risk factors.

Abstract

Clade 2.3.4.4b influenza A(H5N1) viruses have circulated across migratory bird flyways in the United States since 2022, including in Washington, where backyard flock detections have been reported annually. In November 2025, a Washington resident died from acute respiratory failure after receiving a positive influenza A(H5) test result at a hospital laboratory. Washington Public Health Laboratories confirmed influenza A(H5), and genomic sequencing identified influenza A(H5N5) virus (A6 genotype). Polymerase chain reaction testing detected highly pathogenic avian influenza A(H5) virus clade 2.3.4.4b from an apparently healthy backyard flock of ducks and sediment from a watering basin on the patient’s property. Six of eight gene segments from the environmental sample and one duck sample (partial neuraminidase segment) were highly genetically similar to the patient’s virus sequence. Although existing wild bird surveillance had not detected influenza A(H5N5) virus (A6) in the U.S. Pacific Flyway, introduction via wild birds into the environment of the backyard flock was likely the source of the patient’s exposure. The public health investigation identified approximately 135 exposed persons; symptom monitoring and influenza testing detected no additional cases. The overall risk for avian influenza A remains low among the general U.S. population; however, novel avian influenza A virus infection should be considered in persons with symptoms of influenza and potential exposures.

Source: 

Link: https://www.cdc.gov/mmwr/volumes/75/wr/mm7517a2.htm?s_cid=OS_mm7517a2_e&ACSTrackingID=USCDC_921-DM155047&ACSTrackingLabel=Week%20in%20MMWR%3A%20Vol.%2075%2C%20May%207%2C%202026&deliveryName=USCDC_921-DM155047

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Highly Pathogenic Avian #Influenza #H5N1 Clade 2.3.4.4b Virus #Infection in Poultry Farm #Workers, #Washington, #USA, 2024

 

Abstract

Poultry workers in Washington, USA, were infected with highly pathogenic avian influenza A(H5N1) virus and recovered. The viruses were clade 2.3.4.4b genotype D1.1, closely related to viruses causing poultry outbreaks. Continued surveillance and testing for influenza A(H5) clade 2.3.4.4b viruses remain essential for risk assessment and pandemic preparedness of zoonotic influenza viruses.

Source: 

Link: https://wwwnc.cdc.gov/eid/article/31/12/25-1118_article

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Avian #Influenza #H5N5 - #USA (#WHO D.O.N., Dec. 5 '25)

 

5 December 2025

Situation at a glance

On 15 November 2025, WHO was notified of the 71st confirmed human case with influenza A(H5) since early 2024 in the United States of America— the first human case reported in the United States of America since February 2025. 

On 20 November, U.S. Centers for Disease Control and Prevention (CDC) laboratory sequencing verified the virus as influenza A(H5N5), representing the first globally reported human case caused by an influenza A(H5N5) virus. 

The investigation by health authorities in the United States of America is ongoing. 

Contact tracing identified no further cases amongst contacts, and there is currently no evidence of human-to-human transmission. 

Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global surveillance to detect and monitor virological (including genomics), epidemiological and clinical changes associated with emerging or circulating influenza viruses that may affect human health and timely virus sharing for risk assessment. 

Based on available information, the WHO currently assesses the overall public health risk posed by A(H5) viruses as low. 

However, for individuals with occupational risk of exposure, the risk of infection is considered low to moderate.

Description of the situation

On 15 November 2025, WHO was notified of a confirmed human infection with influenza A(H5) in the United States of America—the first reported in the country since February 2025 and the 71st since early 2024. 

On 20 November, CDC laboratory sequencing verified the virus as influenza A(H5N5), representing the first human case of this subtype reported globally. 

The patient was an adult with underlying medical conditions residing in Washington State. 

The patient developed symptoms including fever during the week ending 25 October 2025. 

During the week ending 8 November 2025, the patient was hospitalized with a serious illness and subsequently died on 21 November.

Respiratory specimens collected at the healthcare facility tested positive for influenza A virus by RT-PCR and were presumptive positive for influenza A(H5) at the University of Washington. 

The specimens were sent to the Washington State Public Health Laboratory, where influenza A(H5) was confirmed using the CDC influenza A(H5) assay. 

The sample was received at the CDC on 19 November. 

Sequencing conducted at the University of Washington and at the CDC indicated this was an influenza A(H5N5) virus belonging to the H5 haemagglutinin (HA) clade 2.3.4.4b[1]. 

Public health investigation revealed that the patient kept backyard poultry and domestic birds. 

Additional epidemiological investigations are under way and include active monitoring of anyone who was in close contact with the patient.

Epidemiology

Animal influenza viruses typically circulate within animal populations, but some have the potential to infect humans. 

Human infections are predominantly acquired through direct contact with infected animals or exposure to contaminated environments. 

Based on the original host species, influenza A viruses can be categorized such as avian influenza, swine influenza, and other animal-origin influenza subtypes.

Human infection with avian influenza viruses may result in a spectrum of illness, ranging from mild upper respiratory tract symptoms to severe, life-threatening conditions. 

Clinical manifestations may include conjunctivitis, respiratory, gastrointestinal symptoms, encephalitis (brain swelling), and encephalopathy (brain damage). 

In some cases, asymptomatic infections with the virus have been reported in individuals with known exposure to infected animals and environments.

A definitive diagnosis of human avian influenza infection requires laboratory confirmation. 

WHO regularly updates its technical guidance on the detection of zoonotic influenza, utilizing molecular diagnostic methods such as RT-PCR. 

Clinical evidence indicates that certain antiviral agents, particularly neuraminidase inhibitors (e.g., oseltamivir, zanamivir), have been shown to shorten the duration of viral replication and improve patient outcomes in some cases. 

This antiviral agent should be administered within 48 hours of symptom onset.

High pathogenicity avian influenza A(H5) clade 2.3.4.4b A(H5N5) viruses have been detected in North America in wild birds and wild mammals since at least 2023.[2] 

This is the first laboratory-confirmed human infection with an influenza A(H5N5) virus in the United States of America and reported globally.

Public health response

The CDC and State public health officials have initiated several public health response measures: 

-- Public health officials are conducting surveillance in the area, that included additional case investigations and contact tracing.  

-- Since March 2024, at least 30,100 people have been monitored, and at least 1260 have been tested after exposure to infected animals in the USA. 

-- The CDC conducts enhanced routine surveillance to detect and monitor influenza activity, including infections caused by novel influenza viruses such as avian influenza A(H5).  

-- The CDC recommends that state and local public health departments monitor individuals exposed to birds or other animals (including livestock) suspected of being infected with avian influenza A viruses for the onset of signs and symptoms for up to 10 days after their last exposure. Individuals who develop signs or symptoms of respiratory illness and/or conjunctivitis should be tested for influenza.  

-- The CDC has issued recommendations for the public to avoid unprotected contact with sick or dead animals, including wild birds, poultry, other domestic fowl, and other wild or domestic animals, as well as animal droppings, litter, or materials contaminated by birds or other animals suspected of being infected with the influenza A(H5) virus. 

-- The CDC has interim recommendations for prevention, monitoring, and public health investigations of avian influenza A(H5) virus infections in people. The CDC has also updated recommendations for occupational protection and the use of personal protective equipment (PPE).  

WHO risk assessment

Human infections with avian influenza A(H5) viruses are considered unusual, as A(H5) viruses remain primarily avian influenza viruses. 

However, in rare cases, individuals exposed to infected animals or contaminated environments can become infected with A(H5) viruses.  

Influenza A(H5N5) viruses are detected in birds, including wild birds and domestic poultry, and sometimes in non-human mammals. 

When avian influenza viruses circulate in poultry populations, there is an inherent risk of human infection through exposure to infected birds or contaminated environments. 

As such, sporadic human cases are expected. 

The case had underlying conditions and subsequently died. 

The investigation by health authorities in the United States of America is ongoing and included contact tracing which identified no further cases amongst contacts, and there is currently no evidence of human-to-human transmission. 

This is the 71st confirmed human case of A(H5) in the United States of America since early 2024, and the first since February 2025. 

To date, no human-to-human transmission has been identified in any of the A(H5) cases reported in the United States of America. 

From a global perspective, while a few events with limited human-to-human transmission of zoonotic influenza A(H5) have been described between 1997 and 2007, sustained human-to-human transmission has not been detected to date. 

Based on available information, the WHO currently assesses the overall public health risk posed by A(H5) viruses as low. However, for individuals with occupational risk of exposure, the risk of infection is considered low to moderate.

The risk assessment will be updated as needed, based on any new epidemiological or virological information related to this event.  

WHO advice

This event does not change the current WHO recommendations on public health measures and surveillance of influenza.

Given the current situation of influenza viruses at the human-animal-environmental interface, WHO does not recommend special traveler screening at points of entry or any restrictions.

Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global surveillance to detect and monitor virological (including genomics), epidemiological and clinical changes associated with emerging or circulating influenza viruses that may affect human health and timely virus sharing for risk assessment.

When humans have been exposed to an influenza A virus outbreak in domestic poultry, wild birds, or other animals or when a human case of infection is identified, enhanced surveillance of potentially exposed human populations becomes necessary. This surveillance should consider the healthcare-seeking behaviour of the population and may include a range of active and passive approaches, such as enhanced surveillance in influenza-like illness (ILI)/severe acute respiratory infection (SARI) systems, active screening in hospitals, and among groups at higher occupational risk of exposure. It should also consider other sources, such as traditional healers, private practitioners, and private diagnostic laboratories.

Given the observed widespread occurrence of avian influenza in poultry, wild birds and some wild and domestic mammals, the public should avoid contact with any sick or dead animals. 

Individuals should report deceased birds and mammals or request their removal by contacting local wildlife or veterinary authorities. 

Eggs, poultry meat, and other poultry products should be properly cooked and handled during food preparation. 

Due to potential health risks, consumption of raw milk should be avoided. WHO advises consuming pasteurized milk and if pasteurized milk is not available, heating raw milk until it boils makes it safer for consumption.

In the case of a confirmed or suspected human infection caused by a novel influenza A virus with pandemic potential, including avian influenza viruses, early clinical management, a thorough epidemiologic investigation of animal exposure history, travel, and contact tracing should be conducted even while awaiting the confirmatory laboratory results. 

The epidemiologic investigation should also include early identification of unusual events that could signal person-to-person transmission of the novel virus. 

Clinical samples collected from confirmed or suspected cases should be tested and sent to a WHO Collaborating Center[3] for further characterization. Additional samples should be collected from animals, the environment or any foods suspected to be sources of infection.

WHO advises travelers to countries with known animal influenza outbreaks to avoid farms, live animal markets, areas where animals may be slaughtered and contact with any surfaces potentially contaminated by animal feces. 

Travelers should also wash their hands frequently with soap and water and should follow good food safety and good food hygiene practices. 

If infected individuals from affected areas travel internationally, their infection may be detected either during travel or upon arrival. However, further community level spread is considered unlikely, as this virus has not yet acquired the ability to transmit easily among humans.

Poultry workers should take additional health precautions as they are at higher risk of exposure to avian influenza and other zoonotic diseases due to their close contact with birds and potentially contaminated environments. Farm workers who have direct or close contact with animals or materials infected or contaminated with avian influenza A(H5) virus, should wear appropriate personal protective equipment (PPE) to minimize their risk of exposure.

All human infections caused by a novel influenza A virus subtype are notifiable under the International Health Regulations (IHR,2005) and State Parties to the IHR are required to immediately notify WHO within 24 hours of any laboratory-confirmed case of a recent human infection caused by an influenza A virus due to the potential to cause a pandemic. Evidence of illness is not required for this report. WHO has updated the influenza A(H5) confirmed case definition on the WHO website. 

Currently, there are no readily available vaccines against influenza A(H5) virus for humans. Candidate vaccine viruses for pandemic preparedness have been selected against several A(H5) clades. Existing seasonal influenza vaccines are unlikely to provide protection to against avian influenza A(H5) viruses, based on currently available data. Close monitoring of the epidemiological situation and serological investigations are essential for assessing risk and adjusting risk management measures as needed..

WHO does not recommend any restriction on travel to or trade with the United States of America, based on the information available on the current event.  

Further information

-- Centers for Disease Control and Prevention (CDC). H5 Bird Flu: Current Situation. Available from: https://www.cdc.gov/bird-flu/situation-summary/index.html  

-- Centers for Disease Control and Prevention (CDC). Weekly US Influenza Surveillance Report: Key Updates for Week 46, ending November 15, 2025. Available from: https://www.cdc.gov/fluview/surveillance/2025-week-46.html  

-- World Health Organization, Food and Agriculture Organization of the United Nations, & World Organization for Animal Health (July 2025). Updated joint FAO/WHO/WOAH assessment of recent influenza A(H5N1) virus events in animals and people. WHO, FAO, WOAH; 2025. Available from: https://cdn.who.int/media/docs/default-source/influenza/human-animal-interface-risk-assessments/fao-woah-who-joint-h5-assessment-july-2025.pdf?sfvrsn=fe76b74e_1&download=true

-- World Health Organization. Cumulative number of confirmed human cases of avian influenza A(H5N1) reported to WHO. Geneva: WHO; 2025. Available from: https://www.who.int/publications/m/item/cumulative-number-of-confirmed-human-cases-for-avian-influenza-a(h5n1)-reported-to-who--2003-2025--5-november-2025

-- United States Department of Agriculture, Animal and Plant Health Inspection Service. The Occurrence of Another Highly Pathogenic Avian Influenza (HPAI) Spillover from Wild Birds into Dairy Cattle. Washington, D.C.: USDA; 2025.  Available from: https://www.aphis.usda.gov/sites/default/files/dairy-cattle-hpai-tech-brief.pdf  

-- Centers for Disease Control and Prevention. Recommended composition of influenza virus vaccines for use in the southern hemisphere 2025 influenza season and development of candidate vaccine viruses for pandemic preparedness. Atlanta: CDC; 2025. Available from: https://cdn.who.int/media/docs/default-source/vcm-southern-hemisphere-recommendation-2025/202409_qanda_recommendation_final.pdf?sfvrsn=bd3d90b1_3  

-- Pan American Health Organization / World Health Organization. Epidemiological Alert - Human infections caused by avian influenza A(H5N1) in the Region of the Americas - 5 June 2024. Washington, D.C.: PAHO/WHO; 2024. Available from: https://www.paho.org/en/documents/epidemiological-alert-human-infections-caused-avian-influenza-ah5n1-region-americas-5 

-- Public Health Risk Assessment associated with the spread of zoonotic avian influenza A(H5N1) clade 2.3.4.4b in the Region of the Americas - 12 July 2024. Available from: https://www.paho.org/en/documents/public-health-risk-assessment-associated-spread-zoonotic-avian-influenza-ah5n1-clade  

-- World Health Organization. Mosaic Respiratory Surveillance Framework. Geneva: WHO; 2024. Available from: https://www.who.int/initiatives/mosaic-respiratory-surveillance-framework/ 

-- World Health Organization. Practical interim guidance to reduce the risk of infection in people exposed to avian influenza viruses. Geneva: WHO; 2024. Available from: https://www.who.int/publications/i/item/B09116  

-- World Health Organization. WHO case definition for human infections with avian influenza A(H5) virus requiring notification under IHR (2005) Geneva: WHO; 2024. Available from: https://www.who.int/teams/global-influenza-programme/avian-influenza/case-definitions 

-- World Health Organization. Surveillance for human infections with avian influenza A(‎H5)‎ viruses: objectives, case definitions, testing and reporting. Geneva: WHO; 2024. Available from: https://www.who.int/publications/i/item/B09337

-- World Health Organization. Case definitions for the four diseases requiring notification in all circumstances under the International Health Regulations (2005). Geneva: WHO; 2024. Available from: https://cdn.who.int/media/docs/default-source/documents/emergencies/case-definitions-ihr-four-diseases7f1ee707-3d13-4581-a1af-d5f44f86423a.pdf?sfvrsn=9c68df20_1&download=true  

-- Animal and Plant Health Inspection Service. Confirmation of Highly Pathogenic Avian Influenza in Commercial and Backyard Flocks. Available from: Avian Influenza | Animal and Plant Health Inspection Service (usda.gov)   

-- United States Department of Agriculture, Animal and Plant Health Inspection Service. Detections of Highly Pathogenic Avian Influenza in Mammals. Washington, D.C.: USDA; 2025.  Available from: https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/mammals 

-- United States Department of Agriculture. Animal and Plant Health Inspection Service. HPAI Confirmed Cases in Livestock. Washington, D.C.: USDA; 2024. Available from: https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/hpai-confirmed-cases-livestock 

-- Pan American Health Organization / World Health Organization.  Informe sobre el Grupo de Expertos para la CIPCIZA - Reunión de grupos de trabajo: Vigilancia, Laboratorio y Evaluación de riesgos intersectorial. Washington, D.C.: PAHO/WHO; 2025. Available from: https://www.paho.org/es/documentos/informe-sobre-grupo-expertos-para-cipciza-reunion-grupos-trabajo-vigilancia-laboratorio  

-- Pan American Health Organization / World Health Organization. Colocación y retiro de EPP en trabajadores de granjas ante influenza aviar. Washington, D.C.: PAHO/WHO; 2025. Available from: https://www.paho.org/es/documentos/colocacion-retiro-epp-trabajadores-granjas-ante-influenza-aviar . 

-- Pan American Health Organization / World Health Organization. Colocación y retiro de EPP en trabajadores de la salud ante influenza aviar. Washington, D.C.: PAHO/WHO; 2025. Available from: https://www.paho.org/es/documentos/colocacion-retiro-epp-trabajadores-salud-ante-influenza-aviar. 

-- Pan American Health Organization / World Health Organization. Influenza at the Human-Animal Interface: PAHO Recommendations to Strengthen Intersectoral Work for Surveillance, Early Detection, and Investigation, 9 July 2020. Available from: https://iris.paho.org/handle/10665.2/52563 

-- Pan American Health Organization / World Health Organization. Samples from patients suspected of Influenza A/H5 LABORATORY TESTING ALGORITHM. Available from: https://www.paho.org/en/documents/samples-patients-suspected-influenza-ah5-laboratory-testing-algorithm 

-- Pan American Health Organization / World Health Organization. Technical note: Laboratory Diagnosis of Human Infection with Influenza A/H5. Available from: https://www.paho.org/en/documents/technical-note-laboratory-diagnosis-human-infection-influenza-ah5 

-- Current technical information including monthly risk assessments at the Human-Animal Interface. Available from:  https://www.who.int/teams/global-influenza-programme/avian-influenza/monthly-risk-assessment-summary  

-- WHO. Zoonotic Influenza Outbreak Toolbox. Available from: https://www.who.int/emergencies/outbreak-toolkit/disease-outbreak-toolboxes/zoonotic-influenza-outbreak-toolbox

-- WHO. International Health Regulations (2005). Available from: http://www.who.int/ihr/publications/9789241596664/en/

-- WHO. Manual for the laboratory diagnosis and virological surveillance of influenza (2011). Available from: https://www.who.int/publications/i/item/manual-for-the-laboratory-diagnosis-and-virological-surveillance-of-influenza  

-- Terms of Reference for National Influenza Centers of the Global Influenza Surveillance and Response System. Available from: https://www.who.int/initiatives/global-influenza-surveillance-and-response-system/national-influenza-centres  

-- Pan American Health Organization / World Health Organization. Epidemiological Update: Avian Influenza A(H5N1) in the Americas Region, 15 November 2024. Washington, D.C.: PAHO/WHO; 2024. Available from: https://www.paho.org/en/documents/epidemiological-update-avian-influenza-ah5n1-americas-region-15-november-2024  

-- Pan American Health Organization / World Health Organization. Report of the Regional Consultation for the Strengthening of Intersectoral Work in the Human-Animal Interface of Influenza. 22 March 2023. Washington, D.C.: PAHO/WHO; 2023. Available from: Report of the Regional Consultation for the Strengthening of Intersectoral Work in the Human-Animal Interface of Influenza. March 2023 - PAHO/WHO | Pan American Health Organization 

-- Pan American Health Organization / World Health Organization. Strengthening the intersectoral work for Influenza at the Human Animal Interface in the Region of the Americas: Technical Questions and Answers. 19 May 2023. Washington, D.C.: PAHO/WHO; 2023. Available from: Strengthening the intersectoral work for Influenza at the Human Animal Interface in the Region of the Americas: Technical Questions and Answers - PAHO/WHO | Pan American Health Organization 

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[1] Lam TT, Davis CT, WHO/WOAH/FAO H5 Evolution Working Group. Nomenclature updates to the hemagglutinin gene clade designations resulting from the continued evolution of high pathogenicity avian influenza A(H5) virus clades 2.3.2.1c and 2.3.4.4. bioRxiv. 2025 Nov 23;2025.11.23.690055. doi:10.1101/2025.11.23.690055.

[2] Erdelyan CNG, Kandeil A, Signore AV, et al. Multiple transatlantic incursions of highly pathogenic avian influenza clade 2.3.4.4b A(H5N5) virus into North America and spillover to mammals. Cell Rep. 2024 Jul 23;43(7):114479. doi:10.1016/j.celrep.2024.114479. Epub 2024 Jul 13. PMID:39003741; PMCID:PMC11305400

[3] World Health Organization. WHO Collaborating Centres and Essential Regulatory Laboratories in the Global Influenza Surveillance and Response System (GISRS) [Internet]. Geneva: WHO; 2025. Available from: https://www.who.int/initiatives/global-influenza-surveillance-and-response-system/who-collaboration-center-erl

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Citable reference: World Health Organization (5 December 2025). Disease Outbreak News; Avian Influenza A(H5N5)- United States of America. Available at: https://www/who.int/emergencies/disease-outbreak-news/item/2025-DON590

Source: 

Link: https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON590

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#USA, #Washington State: Grays Harbor County resident dies from #complications of avian #influenza #H5N5 virus (DoH, Nov. 22 '25)

 

The person was infected with the H5N5 virus; the risk to the public remains low

OLYMPIA – A Grays Harbor County resident who was undergoing treatment for H5N5 avian influenza died today. 

The Washington State Department of Health offers its heartfelt condolences to the person’s family and friends.

The person was an older adult with underlying health conditions. 

Out of respect for the family’s privacy, we are not releasing their name, gender, or age. 

The person had been hospitalized in King County since early November.

Testing at the UW Medicine Clinical Virology Lab identified the virus as H5N5, making this the first recorded infection with this variant in a person globally. 

The result was confirmed by the Centers for Disease Control and Prevention (CDC).

The risk to the public remains low. 

No other people involved have tested positive for avian influenza. 

Public health officials will continue to monitor anyone who was in close contact with the patient for symptoms to ensure that human-to-human spread has not occurred. 

There is no evidence of transmission of this virus between people.

The person had a backyard flock of mixed domestic birds. 

DOH testing identified avian influenza virus in the environment of the flock, making exposure to the domestic poultry, their environment, or wild birds the most likely source of exposure for this patient. 

People who had exposure to the backyard flock and environment are also being monitored for symptoms.

Avian influenza is a disease caused by influenza type A viruses, which naturally occur in wild aquatic birds around the world. These viruses can infect other bird species, and occasionally mammals, and can be deadly to domestic birds such as chickens and turkeys. On rare occasions, avian influenza viruses can infect people and make them sick.

People with backyard poultry should avoid contact with sick or dead birds and report illness in poultry to the Washington State Department of Agriculture (WSDA) by calling 1-800-606-3056 or reporting online. 

Veterinarians should report sick or dead domestic animals or livestock suspected of having avian influenza to WSDA. 

Avoid contact with sick or dead wildlife and report sick or dead wild birds or other animals to the Washington State Department of Fish & Wildlife. 

Never handle or allow pets near dead birds or other wildlife.

Avoid eating raw or undercooked food products, such as unpasteurized (raw) milk or raw cheeses, and don’t feed these products to pets.

It is especially important that people who may have exposure to domestic or wild birds get a seasonal flu vaccine. 

While the seasonal flu vaccine will not prevent bird flu infection, it reduces the risk of becoming sick with both human and avian influenza viruses at the same time. 

Though unlikely, infection with both viruses could result in the emergence of an avian influenza virus that is more easily transmitted from person to person. 

Seasonal flu vaccine is recommended for everyone six months and older.

Our website is your source for a healthy dose of information. Get updates by following us on social media.

Source: 

Link: https://doh.wa.gov/newsroom/grays-harbor-county-resident-dies-complications-avian-influenza

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