The Virus Diaries

In this episode, we're breaking down how bird flu has spilled over from wild birds into dairy cow herds, impacting the milk we drink. Join me, Caroline Zeiss, as we explore why this is happening, how we could control it, and what it tells us about the increased risk of bird flu spreading to humans. "The VirusDiaries" is written and recorded by me in Guilford, CT. I’m a Professor of Comparative Medicine at Yale University School of Medicine. Just to be clear, all views expressed in this podcast are mine and do not reflect those of Yale University.

References

Currentnews

https://abcnews.go.com/Health/bird-flu-continuing-spread-animals-us/story?id=121481973

B3.13avian flu in dairy cows

CasertaLC et al., Spillover of highly pathogenic avian influenza H5N1 virus to dairycattle. Nature. 2024 Oct;634(8034):669-676.

Dholakia,V et al., Polymerase mutations underlie early adaptation of H5N1 influenzavirus to dairy cattle and other mammals. bioRxiv 2025.01.06.631435; doi: https://doi.org/10.1101/2025.01.06.631435

Ting-HuiLin et al., A single mutation in bovine influenza H5N1 hemagglutinin switchesspecificity to human receptors.Science386,1128-1134(2024).

Baker,A.L., Arruda, B., Palmer, M.V. et al. Dairy cows inoculated with highlypathogenic avian influenza virus H5N1. Nature 637, 913–920 (2025).

Halwe,N.J., Cool, K., Breithaupt, A. et al. H5N1 clade 2.3.4.4b dynamics inexperimentally infected calves and cows. Nature 637, 903–912 (2025).

FacciuoloA, et al., Dairy cows develop protective immunity against reinfection withbovine H5N1 influenza virus. Nat Microbiol. 2025 Apr 17. doi:10.1038/s41564-025-01998-6.

D1.1avian flu in dairy cows

https://www.aphis.usda.gov/sites/default/files/dairy-cattle-hpai-tech-brief.pdf

https://www.cdc.gov/media/releases/2025/m0106-h5-birdflu-death.html

Vaccinationin dairy cows

https://www.science.org/content/article/companies-start-work-bird-flu-vaccines-cows-despite-major-hurdles

https://www.nmpf.org/nmpf-pushes-for-vaccine-as-usda-unveils-bird-flu-plan-dairy-cattle/

https://www.nmpf.org/dairy-groups-applaud-administration-vaccine-support-thank-usda-for-plan/

https://www.thinkglobalhealth.org/article/time-act-new-bird-flu-spillovers

https://www.cdfa.ca.gov/AHFSS/Animal_Health/HPAI.html

Wastewatertesting

TiszaMJ, Hanson BM, Clark JR, Wang L, Payne K, Ross MC, Mena KD, Gitter A, JavornikCregeen SJ, Cormier J, Avadhanula V, Terwilliger A, Balliew J, Wu F, Rios J,Deegan J, Piedra PA, Petrosino JF, Boerwinkle E, Maresso AW. Sequencing-BasedDetection of Avian Influenza A(H5N1) Virus in Wastewater in Ten Cities. N EnglJ Med. 2024 Sep 26;391(12):1157-1159.

Government  funding to control H5N1

https://www.theguardian.com/us-news/2025/jan/15/biden-administration-bird-flu-funding

https://public3.pagefreezer.com/browse/HHS.gov/21-01-2025T07:38/https://www.hhs.gov/about/news/2025/01/03/hhs-awards-306-million-avian-flu-monitoring-and-preparedness-funding.html

https://www.usda.gov/about-usda/news/press-releases/2025/02/26/usda-invests-1-billion-combat-avian-flu-and-reduce-egg-prices

https://www.aphis.usda.gov/news/agency-announcements/usda-announces-next-steps-effort-support-fight-against-avian-influenza

We are in the midst of the worst bird flu crisis on record. This pernicious virus has established footholds on every continent except Australia. In this episode we focus on wild birds and mammals to look at how the virus entered the US and how it has devastated animal populations across the planet. We’ll shed light on how US and international agencies work together to track and report the virus in birds, animals, and humans, and how recent US federal layoffs threaten to derail this complex system. 

How bird flu entered the US

https://www.cbc.ca/news/canada/newfoundland-labrador/avian-flu-newfoundland-labrador-1.6304817

https://www.usgs.gov/centers/nwhc/science/avian-influenza-surveillance

Caliendo V, Lewis NS, Pohlmann A, et al. Transatlanticspread of highly pathogenic avian influenza H5N1 by wild birds from Europe toNorth America in 2021. Scientific reports. 2022; 12: 11729.

Bird flu in wild birds

Klaassen, M., Wille, M.The plight and role of wild birds in the current bird flu panzootic. NatEcol Evol 7, 1541–1542 (2023). 

https://www.ksnt.com/kansasoutdoors/kansas-biologist-estimates-14000-birds-have-fallen-ill-or-died-of-bird-flu/

Bird flu in wild mammals

https://english.elpais.com/science-tech/2025-02-14/worst-avian-flu-crisis-ever-recorded-spreads-across-antarctica.html

Rimondi A, Vanstreels R,Olivera V, et al. Highly Pathogenic Avian Influenza A(H5N1) Viruses fromMultispecies Outbreak, Argentina, August 2023. Emerging InfectiousDiseases. 2024;30(4):812-814. doi:10.3201/eid3004.231725.

https://www.npr.org/sections/goats-and-soda/2025/02/07/g-s1-46402/bird-flu-wild-animals-mammals-virus

Public databases reporting cases of avian fluin birds, animals and humans

https://www.aphis.usda.gov/sites/default/files/wild-bird-strategic-plan.pdf

https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/wild-birds

https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/commercial-backyard-flocks

https://www.cdc.gov/bird-flu/avian-timeline/2020s.html

https://www.cdc.gov/bird-flu/php/avian-flu-summary/chart-epi-curve-ah5n1.html

https://inspection.canada.ca/en/animal-health/terrestrial-animals/diseases/reportable/avian-influenza/latest-bird-flu-situation/hpai-dashboards

https://www.who.int/philippines/news/detail-global/30-03-2024-2023--outbreaks-of-avian-influenza

Federal layoffs impacting bird flu surveillance

https://www.npr.org/2025/03/05/nx-s1-5318687/usda-fired-federal-employees-probationary-osc-mspb

https://www.nbcnews.com/politics/doge/usda-accidentally-fired-officials-bird-flu-rehire-rcna192716

https://www.politico.com/news/2025/02/16/trump-administration-firings-bird-flu-response-00204542

https://www.cdc.gov/mmwr/volumes/74/wr/mm7404a2.htm

https://www.cnn.com/2025/02/14/politics/probationary-federal-employees-agencies-firings-doge/index.html

https://www.cnn.com/2025/01/21/politics/trump-executive-action-world-health-organization-withdrawal/index.html

In January, egg prices reached an all-time high.  And are predicted to rise by over 40% in 2025.This is in part attributed to a "man-made crisis" caused by culling millions of chickens when bird flu appears in a flock. In this episode we look at why culling is practiced, how it affects the production of eggs, and the USDA's new plan to control the virus and bring down egg prices

Sources referenced in this episode

https://www.usatoday.com/story/money/food/2025/02/26/egg-prices-to-rise-2025-usda/80452571007/

https://www.foxnews.com/video/6368903426112

https://www.forbes.com/sites/mollybohannon/2025/03/06/elon-musk-says-biden-ordered-insane-slaughter-of-150-million-chickens-but-culls-are-usda-policy-to-stop-bird-flu-spread/

https://www.avma.org/news/cat-deaths-linked-bird-flu-contaminated-raw-pet-food-sparking-voluntary-recall

https://www.wsj.com/opinion/agriculture-secretary-brooke-rollins-my-plan-to-lower-egg-prices-6be0f881

https://www.science.org/content/article/u-s-conditionally-approves-vaccine-protect-poultry-avian-flu

https://www.nationalchickencouncil.org/bipartisan-bicameral-members-of-congress-seek-assurances-for-chicken-exports-as-part-of-bird-flu-strategy/

https://www.foodandwaterwatch.org/wp-content/uploads/2025/03/RPT2_2502_EconomicCostEggs.pdf