The U.S. confirmed a fatal H5N5 infection in Washington state—the first recorded human case of this strain—and domestic poultry losses continued to mount, driven largely by sustained activity in northern Indiana. Abroad, Europe is experiencing a continued rise in H5N1 detections, with 2025 totals now pushing beyond any prior year. East Asian countries reported additional H5 events across Japan, South Korea, and India, while China disclosed previously unreported pediatric H9N2 infections. Africa also re-emerged after months of limited activity, including sizable flock losses in Nigeria and South Africa. Lastly, a new study shows avian flu viruses can withstand human fever, which carries serious implications for human infections.
Study Shows Bird Flu Viruses Withstand Fever, Increasing Risk of Severe Human Infection
A new study in Science, led by the Universities of Cambridge and Glasgow, shows that avian influenza viruses can replicate at temperatures typical of human fever, making them harder to suppress once infection occurs. Using mouse models, researchers found that fever-level temperatures quickly blocked human-origin flu viruses, while avian viruses—adapted to thrive in birds’ higher body heat—continued replicating and caused severe disease. These findings could have severe implications if the virus’ spread accelerates among humans (University of Cambridge, 2025).
Washington H5N5 Infection: Confirmed Fatal
Washington health officials confirmed that the patient previously reported as hospitalized with H5N5 has died, marking the first known human infection with this strain and the first U.S. human avian flu case since February. The patient had underlying health conditions and kept a mixed backyard flock with wild-bird exposure. Officials said no close contacts have tested positive and no human-to-human transmission has been identified (Soucheray, 2025a).
Commercial Flock Losses Continue Nationwide, Indiana Remains the Center of Activity
Indiana remains the main hotspot of U.S. commercial HPAI activity, with about 873,000 birds affected across 62 farms since early October, primarily at egg-layer and meat-duck operations (Miller, 2025). Since the prior edition of this report on November 21, the state has lost an additional 273,000 chickens to HPAI (United States Department of Agriculture, n.d.). North Carolina also confirmed two turkey breeder outbreaks on November 18 and 21, affecting a combined 17,800 birds (Graber, 2025c). In South Dakota, a 24,000-bird turkey breeder outbreak was reported in Edmunds County on November 24, just five days after a 35,400-bird outbreak in the same county (Graber, 2025a). Iowa also reported new activity, confirming a 17,600-bird turkey outbreak on December 3—its first commercial case since October (Graber, 2025e).
U.S. Lawmakers Urge USDA to Restore Full HPAI Surveillance Capacity
A letter sent on November 24 by twenty-five House Democrats urged Agriculture Secretary Brooke Rollins to restore avian influenza surveillance to full capacity, citing reports that USDA’s National Animal Health Laboratory Network paused weekly coordination calls during the government shutdown. The lawmakers noted that APHIS confirmed 90 new HPAI detections in the past month across commercial and backyard flocks and emphasized that ongoing wild bird migration increases seasonal risk. They argued that reduced coordination limits timely information sharing needed to protect poultry producers facing potential flock losses and broader supply impacts (Graber, 2025b).
European H5N1 Worsening Across Commercial Poultry, Captive Birds, and Wildlife
Europe continues to see broad H5N1 circulation, with the European Commission’s November 26 update documenting nearly 90 new commercial poultry outbreaks across 13 countries in the week leading up to the report. This brings the 2025 total to 577 poultry-farm detections, already exceeding full-year counts for 2023 and 2024. France and Germany saw the largest increases; in France, 68 outbreaks have been confirmed since October affecting nearly 800,000 birds. Notably, several of these infections occurred in duck flocks vaccinated under France’s national HPAI vaccination campaign. Captive bird detections continue to rise, with 13 outbreaks reported between November 20 and 26 across several states. Wild bird activity also remains high, with more than 2,800 cases recorded so far this year and over 460 newly reported, led by Germany. H5N1 remains the dominant subtype, with one H5N5 detection in a wild bird in northern Scotland (Linden, 2025b).
Asia Confirms Multiple New H5 Outbreaks, With China Also Reporting Previously Undisclosed Human H9N2 Cases
Japan, South Korea and other Asian countries have confirmed new detections of HPAI. Japan recorded two late-November and early-December broiler outbreaks involving 48,000 and 75,000 birds, bringing its total since mid-October to six. South Korea reported an H5 detection in a flock of about 130,000 laying hens, raising its season total to six outbreaks, with wild-bird positives also reported. Elsewhere, Iraq detected H5N1 after a one-month gap, and Uttarakhand in India confirmed five H5N1-positive poultry flocks totaling more than 21,000 birds. China also reported four previously undisclosed human H9N2 infections in young children, all with onset between September 30 and October 12. No information was released on poultry exposure or the children’s current health status (Linden, 2025c).
New H5N1 Cases In Africa After Months of Limited Activity
In a recent report from the World Organisation for Animal Health (WOAH), Nigeria disclosed that H5N1 reappeared in mid-October after five months with no detections, with multiple clustered backyard outbreaks and significant poultry losses. Additionally, South Africa notified WOAH of H5N1 outbreaks in the Western Cape, including one commercial farm with more than 150,000 birds and confirmed infections in about 40 wild birds (Linden, 2025a).
References
Graber, R. (2025a, November 26). Avian influenza hits South Dakota turkey breeder hens. WATTPoultry.com. https://www.wattagnet.com/poultry-meat/diseases-health/avian-influenza/news/15772822/avian-influenza-hits-south-dakota-turkey-breeder-hens
Graber, R. (2025b, November 26). US Congress members push for full HPAI surveillance. WATTPoultry.com. https://www.wattagnet.com/poultry-meat/diseases-health/avian-influenza/news/15772801/us-congress-members-push-for-full-hpai-surveillance
Graber, R. (2025c, December). HPAI hits 2 poultry flocks in North Carolina, 3 in Ontario. WATTPoultry.com. https://www.wattagnet.com/poultry-meat/diseases-health/avian-influenza/news/15772967/hpai-hits-2-poultry-flocks-in-north-carolina-3-in-ontario
Graber, R. (2025d, December 3). HPAI resurfaces in Colombia, situation resolved in Guatemala. WATTPoultry.com. https://www.wattagnet.com/poultry-meat/diseases-health/avian-influenza/news/15773225/hpai-resurfaces-in-colombia-situation-resolved-in-guatemala
Graber, R. (2025e, December 4). New avian flu cases reported in Iowa, Manitoba, Saskatchewan. WATTPoultry.com. https://www.wattagnet.com/poultry-meat/diseases-health/avian-influenza/news/15773320/new-avian-flu-cases-reported-in-iowa-manitoba-saskatchewan
Linden, J. (2025a, November 25). Further avian flu outbreaks in Egypt, Nigeria, South Africa. WATTPoultry.com. https://www.wattagnet.com/poultry-meat/diseases-health/avian-influenza/news/15772734/further-avian-flu-outbreaks-in-egypt-nigeria-south-africa
Linden, J. (2025b, December). Avian flu hits poultry farms in 13 European states. WATTPoultry.com. https://www.wattagnet.com/poultry-meat/diseases-health/avian-influenza/news/15772927/avian-flu-hits-poultry-farms-in-13-european-states
Linden, J. (2025c, December 4). More avian flu outbreaks reported in Japan, South Korea. WATTPoultry.com. https://www.wattagnet.com/poultry-meat/diseases-health/avian-influenza/news/15773278/more-avian-flu-outbreaks-reported-in-japan-south-korea
Miller, C. J. (2025, November 26). Over 800,000 Birds Impacted by Bird Flu in LaGrange, Elkhart Counties Since Oct. 9 | Hoosier Ag Today. Hoosieragtoday.com. https://www.hoosieragtoday.com/2025/11/25/bird-flu-update-2/?amp=1
Soucheray, S. (2025a, November 24). Center for Infectious Disease Research and Policy. CIDRAP. https://www.cidrap.umn.edu/avian-influenza-bird-flu/washington-state-officials-confirm-h5n5-avian-flu-patient-has-died
Soucheray, S. (2025b, December 3). Center for Infectious Disease Research and Policy. Umn.edu. https://www.cidrap.umn.edu/marburg/quick-takes-marburg-cases-reach-13-avian-flu-detections-alaska
United States Department of Agriculture. (n.d.). H5N1 Influenza | Animal and Plant Health Inspection Service. Animal and Plant Health Inspection Service. https://www.aphis.usda.gov/h5n1-hpai
University of Cambridge. (2025, November 27). Bird flu viruses are resistant to fever, making them a major threat to humans. University of Cambridge. https://www.cam.ac.uk/research/news/bird-flu-viruses-are-resistant-to-fever-making-them-a-major-threat-to-humans