Discussion thread: H5N1 avian flu in US dairy cows including human cases (poultry, dairy workers) - March 24, 2024 +

[Commonground]

HOGVET51
MAY 19, 2025​

H5N1 Dairy (Re)infections and the Bifurcated World of the National Milk Testing Strategy (NMTS)

Excerpts:

​

I had written quite extensively last week regarding questions I had regarding all the Idaho cases. Dr. Scott Leibsle, the State Veterinarian, was kind enough to briefly e-mail me some very helpful responses to inquiries I had sent him. I’d like to summarize his honest assessments to date of what is occurring in Idaho’s 4 counties with active infection:

1. First, he stated that it is in reality unknown how many cases are in previously infected herds versus newly infected herds because many dairies didn’t report having symptoms a year ago when the first wave of H5N1 came through Idaho dairies. His opinion is that nearly all Idaho dairies were either exposed to or affected by H5N1 in 2024….so it’s likely that the currently affected dairies are either getting it for a second time or never got rid of it.
2. He stated that B3.13 the only agent involved (no D1.x has been diagnosed)...

​-snip-

Ultimate infected herd outcomes are critical, because we are still operating a cooperative H5N1 dairy “control” program based on the assumption that we can “isolate and exhaust” the B3.13 virus in infected herds. Evidence from Colorado and negative NMTS states would argue that could be possible. Idaho, Texas, and California repeat infections make that prospect look extremely unlikely.​

-snip-

Finally, we have building evidence that H5N1 is an area spread whole herd infection, not confined on the farm to lactating animals only, as laid out in emerging work and thought by Lombard and others (The One Health challenges and opportunities of the H5N1 outbreak in dairy cattle in the United States - Journal of Dairy Science. This work would also implicate at least potential roles for beef cattle populations as reservoirs or amplifying sites for H5N1 outbreaks. No one has conducted serological or PCR sampling to date to my knowledge in areas with coexisting large beef cattle, dairy, and poultry populations with B3.13 H5N1 outbreaks in dairy and poultry (e.g. California, Colorado, Idaho, TX). Lack of testing does not equate to lack of the possibility for such occurrences with a virus that seems to spread indiscriminately in livestock dense areas to new dairy herds and poultry flocks.​

... https://hogvet51.substack.com/p/h5n1-dairy-reinfections-and-the-bifurcated

 

[Commonground]

May 23, 2025
Animal Health Body Says Vaccines Needed to Protect Humans and Trade

Excerpts:

"Vaccination is a tool, it's a very good tool when it exists, but it's up to each country, region, or group of countries to identify in which case it will be useful to use it or not," Director General Emmanuelle Soubeyran told Reuters ahead of the start of WOAH's general assembly on Sunday.

Bird flu has also spread to mammals, including dairy cows in the United States, and infected hundreds of people, raising concerns it could spark a new pandemic.

https://www.usnews.com/news/world/a...s-vaccines-needed-to-protect-humans-and-trade

 

[Pathfinder]

Avian Influenza in Cats: Latest H5N1 Updates with Ian Gill Bemis | AAHA HPAI Recap
American Animal Hospital Association
13 Jun 2025
---------------------------
Excerpts from the video:

Beis Gil Bemis from University of Maryland, expert on avian influenza outbreaks in cat:
-Publication soon to come, currently in the works on antiviral research
-Systematic review, we found a 90% approximate case fatality rate
-We have an ongoing serosurvey in outbreak regions targeting both domestic and rural cats and while I have not tested enough samples... we have found a sero prevalence that is relatively low so far. So combined with our data that's very preliminary and the data that we found from the serosurveys and our systematic review, it appears that this is still an emerging pathogen, that this is not endemic in cats and when you consider the case fatality rate, it appears that it is unlikely to become endemic in cats...
-----------------------------
See also:

Hattip Tetano

https://flutrackers.com/forum/forum/welcome-to-the-scientific-library/surveillance-and-epidemic-control/1013614-open-forum-infect-dis-avian-influenza-virus-infections-in-felines-a-systematic-review-of-two-decades-of-literature​

 

[Commonground]

July 7, 2025
H5N1 Dairy Crisis Enters Critical Phase as Economic Losses Exceed $950 Per Infected Cow
H5N1 devastates milk yield with 900kg losses per cow while 90% spread silently. Your milking parlor = ground zero. Are you prepared?

​EXECUTIVE SUMMARY: The dairy industry’s traditional biosecurity playbook just became obsolete—H5N1 has rewritten the rules by turning your milking parlor into the primary disease transmission vector, not wild birds. Cornell University’s groundbreaking research reveals that infected operations face catastrophic losses averaging $950 per clinically affected cow, with total herd impacts reaching $737,500 for large-scale operations[1][2]. Mathematical modeling confirms current industry interventions have prevented only 175.2 additional outbreaks, proving our response strategies are barely scratching the surface of this evolving threat. While Europe congratulates itself on zero confirmed cases, research shows European cattle breeds possess identical susceptibility patterns to U.S. herds, with the virus’s inevitable arrival being a matter of “when,” not “if”[1]. The virus spreads with alarming stealth—90% herd exposure despite only 20% showing clinical symptoms—making traditional visual monitoring completely inadequate for early detection[3]. Canada’s proActive program has successfully prevented H5N1 entry through mandatory biosecurity integration, proving that proactive preparation works infinitely better than reactive crisis management[1]. Forward-thinking producers must immediately abandon outdated poultry-focused biosecurity models and implement “Fortress Farm” protocols before this industry-defining threat reaches their operation.



KEY TAKEAWAYS

• Eliminate raw waste milk feeding immediately to prevent 50%+ mortality in farm cats and potential viral amplification—switch to pasteurized alternatives or milk replacer to break the deadliest transmission pathway that most operations ignore. This single change can prevent catastrophic spillover events that transform your farm into a multi-species disease reservoir.
• Implement dedicated milking parlor biosecurity with N95 respirators, dedicated gloves per cow, and complete equipment disinfection cycles after every session—the mammary gland-centered pathogenesis means your milking equipment has become the primary cow-to-cow transmission vector, not respiratory droplets. Operations ignoring this shift face inevitable herd-wide contamination within days of introduction.
• Adopt Canadian-style “closed herd” philosophy with mandatory 30-day quarantine and pre/post-movement testing for all animal introductions—mathematical models show this approach prevents the interstate spread patterns that have devastated over 959 U.S. dairy herds across 16 states. The $28,000 USDA biosecurity support per farm proves prevention costs far less than outbreak response.
• Install precision monitoring systems that detect rumination and milk production declines 5-7 days before clinical diagnosis—Cornell research confirms behavioral changes precede visual symptoms, enabling isolation protocols that could prevent the 90% herd exposure rates documented in infected operations. Early detection transforms potential $737,500 losses into manageable, isolated cases.
• Prioritize genetic resilience in breeding decisions as H5N1 targets your highest-producing, most genetically valuable multiparous cows disproportionately—the virus’s mammary gland tropism means superior TPI scores amplify economic vulnerability, requiring breeding programs to balance production traits with disease resistance markers. This genetic shift protects decades of genetic investment from permanent productivity compromises.

​https://www.thebullvine.com/news/h5...-economic-losses-exceed-950-per-infected-cow/

​

 

[Michael Coston]

CDC Scales Back Updates On H5N1 Bird Flu

CDC Scales Back Updates On H5N1 Bird Flu






#18,786

It has been widely reported overnight that the CDC has ended their Emergency Response to H5N1 Avian flu, but the only overt sign I've found thus far on the CDC website is the above statement indicating that updates to their H5 Bird Flu: Current Situation webpage will now be made monthly.





Admittedly, the number of human cases in the United States has remained stable since February (although some cases may have been missed). If an agency felt the need to temporarily stand down - I can see why this recent respite would seem the ideal time to do so.

That said, last fall in MMWR: Serologic Evidence of Recent Infection with HPAI A(H5) Virus Among Dairy Workers, we learned that some percentage (7% in the study) of dairy workers have likely been infected asymptomatically.

Complicating matters, farm workers are often reluctant to come forward - even when symptomatic - due to concerns over immigration entanglements or being fired (see EID Journal: Avian Influenza A(H5N1) Virus among Dairy Cattle, Texas, USA), and farmers remain reluctant to have their herds tested.​

The USDA's Dairy Herd Status Programwebsite was last updated in late June, and still shows only 111 herds (out of an est. 36,000) from 20 states enrolled in the voluntary herd monitoring program.

Despite a recent decline in H5N1 positive dairy herds, a study published 2 months ago (see Nature: A Mathematical Model of H5N1 Influenza Transmission in US Dairy Cattle), strongly suggests that the H5N1 virus is far more widespread in U.S. dairy cows than has been reported.​

We've also seen sharp decline in the number of wildlife H5 detections submitted by the states to the USDA in 2025. How much of this lull is due to an actual reduction in the virus in the wild, and how much is a result of reduced testing, is unknown.



Typically - at least in temperate climes - avian flu activity diminishes sharply during the summer months, but often resurges in the fall when migratory birds resume their annual southbound migration.

While we can never know what the next migration will bring, there is a high likelihood that avian flu activity will resume in the fall, and that new genotypes may accompany that upcoming wave.

Meanwhile, H5Nx continues to spread, and evolve, around the world. Any perceived drop in H5's threat level could easily prove temporary.​

Of course, H5N1 isn't guaranteed to spark the next pandemic. It has loomed large several times in the past, only to recede back into the shadows. There may even be an insurmountable `species barrier' that prevents H5 from ever spreading easily in humans (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?).

But HPAI H5 is just one of many respiratory viruses with pandemic potential. Last summer the WHO unveiled an expanded Pathogens Prioritization report, increasing the number of priority pathogens to more than 30.​

Additions included 7 different influenza A subtypes (H1, H3, H3, H5, H6, H7, and H10), 5 bacterial strains that cause cholera, plague, dysentery, diarrhea and pneumonia, and several coronavirus contenders.




In terms of likelihood of emergence, H5N1 is actually fairly far down the CDC's IRAT list. Currently the CDC ranks a Chinese EA H1N1 `G4' swine virus at the very top of their list, with 3 other North American swine variant viruses scoring higher than H5N1.




All reasons why it is important to keep a wary eye on more than just HPAI H5, and why pandemic preparedness should be based on dealing with the emergence of a wide range of respiratory pathogens, rather than just focused on the influenza subtype du jour.


For more on this, you may wish to revisit:

PAHO IRIS: Developing Respiratory Pathogen Pandemic Preparedness Plans
​

,

https://afludiary.blogspot.com/2025/07/cdc-scales-back-updates-on-h5n1-bird-flu.html
​

 

[sharon sanders]

Rant -

We need proactive surveillance, not reactive surveillance. Since the beginning of the human cases in 2022 the US has failed. Our case list includes all full and partial test positive persons. Our count is 93. And not on our list are the reported dozen or so dairy cattle workers at the beginning of the known cattle outbreaks who had respiratory and conjunctivitis systems. The probable count is most likely over 100 and does not include unknown cases. Typically in outbreaks the known cases are a fraction of the real total - especially if the illness is mild.

When the first human H5N1 case was diagnosed in 2022 we should have instituted a very aggressive program to determine the real spread in the US - testing both wild animals, domestic animals, and humans. We can not go back now. That window closed.

As this site has said many times, do not wait for any government to "save" you. Not for hurricanes, or any other threat. They are often too little, too late.

No one knows what will happen with H5N1. Maybe nothing. Maybe all of the outbreaks are diminishing and the virus will disappear. I hope so but nature rules and we are not closely following her lead.

Take care of you (and your animals).

 

[Pathfinder]

...
H5 detection in wastewater in the past six weeks

Time Period: May 25, 2025 - July 05, 2025​

...
Screenshots:

​

https://www.cdc.gov/nwss/rv/wwd-h5.html

 

[Commonground]

Media
7/28/25
California dairy farmers got millions to cover bird flu losses. Critics say that's part of the problem

​
The federal government has paid California dairy farms more than $230 million to subsidize losses in milk production resulting from bird flu, records show, an amount that the dairy industry expects to climb higher as more claims for damages are processed.

The H5N1 bird flu has swept through more than 75% of California’s 1,000 dairy farms since August 2024, sickening cattle and leading to steep dropoffs in milk production.

Farmers were able to get relief under a U.S. Department of Agriculture program known as the Emergency Assistance for Livestock, Honeybees and Farm-Raised Fish Program, or ELAP. The program usually provides assistance for farmers impacted by wildfires, drought and flooding but was opened up for dairy farmers last year as bird flu began ravaging their cows.
​
... https://www.yahoo.com/news/articles/california-dairy-farmers-230-million-100000558.html

 

[Commonground]

from previous post (#498)
Excerpt

He said the virus caused cows to abort their pregnancies, and often prevented them from getting pregnant again. A dairy cow that doesn't give birth doesn't produce milk. In other cases, he said the udders were so scarred by the disease that the cows were unable to produce milk at levels prior to infection.

"There's a whole other version I'm not sure the public understands, which is the huge impact on reproduction," he said.
​

He also noted many animals died — especially when the outbreak first hit last fall, and the newness of it combined with the blazing heat of the Central Valley felled 10% to 15% of many California herds.​

 

[Commonground]

7/28/25
Wyoming
Game And Fish Says Disease Caused Dozens Of Doves Drop Dead In Rock Springs

​
ROCK SPRINGS — At first, it was just a few. A lifeless dove found near a curb. Another beneath a tree.

Then dozens more, mostly found within a tight radius in Rock Springs known as the “Tree Streets.”

“I don’t have an exact number,” said Regina Dickson, an information and education specialist with the Wyoming Game and Fish Department. “But over 30 that we know of — and we’ve got a lot more calls coming in.”

What’s killing these doves? A virus called avian paramyxovirus — deadly to pigeons and doves, including both the non-native Eurasian collared dove and the migratory mourning dove.

This particular strain is not believed to affect humans or pets, but wildlife officials are watching it closely, the agency told Cowboy State Daily on Monday.

“There’s no concern at this point for zoonotic transmission,” said Liz Wheeler, a disease biologist at the Wyoming Game and Fish Wildlife Health Lab. “The initial testing for avian influenza came back negative, and that was the concern for potential human exposure.”

While some strains of paramyxovirus — like Newcastle’s disease — can severely impact poultry, Wheeler confirmed that the dead doves found in Rock Springs initially tested negative for that more virulent form.

But the state is following protocol and sending the samples out for confirmation.

“There’s no reason to believe those results will change,” Wheeler said. “But because Newcastle’s disease would be such a big deal, they send it off for confirmation just to be sure.”
​
In The ‘Tree Streets’


The first confirmed cases came from a Rock Springs neighborhood where the streets are named after trees, a part of town locals sometimes refer to as the “Tree Streets.”

While most reports have come from Rock Springs, Game and Fish “did get a call about some dead doves in Casper” last week, Dickson said.

Wheeler clarified that no testing has been done on birds from Casper and there is no confirmed outbreak of a disease there.

“Almost all the affected birds came from a very small area in Rock Springs,” Wheeler said.

The virus, which is always present in the environment, spreads quickly when birds congregate in high numbers.

“It’s similar to the flu in humans,” Dickson said. “When you have a large population congregating and one gets sick, it spreads fast.”
​
continued: https://cowboystatedaily.com/2025/0...ed-dozens-of-doves-drop-dead-in-rock-springs/

 

[Pathfinder]

Related to:

Hat tip Tetano:
https://flutrackers.com/forum/forum...models-but-retain-avian-virus-like-properties

H5N1 found in dairy cattle retains preference for infecting birds, representing low risk to humans

​Scientists from St. Jude Children’s Research Hospital found that H5N1 viruses in dairy cows are more similar to viruses sampled from birds than influenza viruses that are better at infecting humans.​

Memphis, Tennessee, July 28, 2025

New research from St. Jude found flu in dairy cows is currently staying closer to it avian roots instead of mutating to better infect mammals. Avian influenza virus from the ongoing outbreak in dairy cattle appears to be keeping its bird-infecting features rather than adapting to better infect other mammals, according to a new study from St. Jude Children’s Research Hospital. Since 2024, when scientists first detected H5N1 bird flu in dairy cattle, they have worried that the virus would use the animals as a bridge to mutate and gain the ability to better infect and spread in humans. The St. Jude researchers tested a panel of these viruses from dairy cows, finding they had more molecular and biological features in common with avian than human flu viruses. In addition, the viruses from cows could not transmit through the air between mammals, though direct infection of an individual human from close contact with infected dairy cattle is possible. The findings were published recently in Nature Communications.

“We found that these flu viruses from cow udders are not under a lot of pressure to mutate to better infect other mammals such as humans,” said corresponding author Richard Webby, PhD, St. Jude Department of Host-Microbe Interactions. “For now, the risk of becoming a pandemic threat to humans appears low, though the risk of direct infection for those working with these animal remains high.”

The scientists compared five flu viruses sampled from dairy cows to the closest related strains found in birds and humans. In almost all cases, the bovine viruses more closely resembled the avian influenza strains. The viral proteins from the cow and bird flu strains had the most similar genetic sequences and bound to receptors on avian cells far more efficiently than to receptors found on mammalian cells. Those features indicate that the virus is unlikely to spread well in humans in its current form.

Assessing bovine influenza virus’s risk to humans

While they may not infect humans efficiently, these viruses from dairy cows have already caused at least 41 infections in people through close contact with dairy cattle. The scientists therefore wanted to know if the viruses could spread between humans, so they studied a mammalian model of human influenza infection. The models could not pass the bovine flu to each other through the air. However, these models could spread the virus through direct contact. The lack of airborne transmission indicates a low risk of spreading between humans, but the other experiments suggest that there is still a threat of direct infection. Therefore, the scientists looked to see if current interventions for flu could help treat such infections.

They started by examining the immune molecules in the blood of people vaccinated against avian influenza. “We found that when we tested sera from patients in a clinical trial for this flu vaccine for a different strain, they had some cross-protection against these bovine viruses,” said first author Tom Fabrizio, PhD, St. Jude Department of Host-Microbe Interactions.

If vaccines fail, then physicians will reach for antivirals to treat an infected individual. There are two antivirals used in patients with influenza, so the researchers measured how well both controlled H5N1 infections from the cow viruses in the lab and studied genetic markers of treatment resistance.

“Our results predict that these antivirals should work effectively against these viruses,” Fabrizio said. “We also saw no indication that they’re gaining any ability to resist these drugs.”

While the results are encouraging, they do not mean that these bovine viruses are innocuous. Infected mammalian models still showed many signs of sickness, as have some humans. In addition, the virus continues to evolve, so these results may not apply in the future if a new variant arises.

“Right now, these bovine flu viruses pose a threat at the individual level, specifically to those working closely with infected animals or drinking raw infected milk, rather than the population level,” Webby said. “But we need to remain vigilant for human infections, as each new person infected is another chance for this virus to mutate to better infect and spread among us.”

Authors and funding

The study’s other authors are Ahmed Kandeil, Walter Harrington, Jeremy Jones, Trushar Jeevan, Konstantin Andreev, Patrick Seiler, Jonathan Fogo, Morgan Davis, Jeri Carol Crumpton, John Franks, Jennifer Debeauchamp, Peter Vogel and Elena Govorkova, St. Jude; Scanlon Daniels, Circle H Headquarters LLC; Rebecca Poulson, University of Georgia; Andrew Bowman, The Ohio State University; and Ahmed Kandeil, Center of Scientific Excellence for Influenza Viruses National Research Centre.

The study was supported by National Institute of Allergy and Infectious Diseases (contract 75N93021C00016) and ALSAC, the fundraising and awareness organization of St. Jude.​
...
https://www.stjude.org/media-resour...e-retains-preference-for-infecting-birds.html


Read the full text of the Nature Communications article:

Genotype B3.13 influenza A(H5N1) viruses isolated from dairy cattle demonstrate high virulence in laboratory models, but retain avian virus-like properties

Nature Communications, published July 23, 2025​

 

[Pathfinder]

Surveillance on California dairy farms reveals multiple sources of H5N1 transmission (biorxiv, Preprint, August 1, 2025)

Surveillance on California dairy farms reveals multiple sources of H5N1 transmission

Posted August 01, 2025.
Download PDF​

View ORCID ProfileA.J. Campbell, View ORCID ProfileMeredith Shephard, View ORCID ProfileAbigail P Paulos, View ORCID ProfileMatthew Pauly, View ORCID ProfileMichelle Vu, View ORCID ProfileChloe Stenkamp-Strahm, View ORCID ProfileKaitlyn Bushfield, Betsy Hunter-Binns, Orlando Sablon, View ORCID ProfileEmily E Bendall, William J Fitzimmons, View ORCID ProfileKayla Brizuela, View ORCID ProfileGracie Quirk, Nirmal Kumar, Brian McCluskey, View ORCID ProfileNishit Shetty, View ORCID ProfileLinsey C Marr, View ORCID ProfileJenna Guthmiller, Kevin Abernathy, View ORCID ProfileAdam S Lauring, Blaine T Melody, Marlene Wolfe, Jason Lombard, View ORCID ProfileSeema S Lakdawala
doi: https://doi.org/10.1101/2025.07.31.666798​​
​

Abstract

Transmission routes of highly pathogenic H5N1 between cows or to humans remain unclear due to limited data from affected dairy farms. We performed extensive air, farm wastewater, and milk sampling on 14 H5N1 positive dairy farms across two different California regions. Virus was detected in the air in milking parlors and from exhaled breath of cows. Infectious H5N1 virus was detected in the air and water streams; sequence analysis revealed viral variants on a farm in these locations. Longitudinal analysis of milk from the individual quarters of cows revealed a high prevalence of subclinical H5N1 positive cows and a heterogeneous distribution of infected quarters that maintained a consistent pattern over time. Our data highlight potential modes of H5N1 transmission on dairy farms.

Competing Interest Statement


SSL and LCM receive funds from Flu Lab and NIH. ASL receives funds from Flu Lab, NIH, and CDC. ASL receives consulting fees and research support from Roche, outside of the submitted work.
​...

https://www.biorxiv.org/content/10.1101/2025.07.31.666798v1

----------------------------------------------------------

From the PDF link above:
...
Discussion

Elucidating the routes of transmission of H5N1 between cows is critical to defining
successful mitigation strategies. In this study we successfully detected H5N1 in the air and in
reclaimed farm wastewater on separate dairy farms on multiple days. This included infectious air
samples from three different milking parlors and viral RNA from the exhaled breath of rows of
cows on two distinct farms. Additionally, we detected viral RNA in farm wastewater at multiple
sites on various farms and infectious virus at two different sites on the same farm. Together, these
results highlight the expansive environmental contamination of H5N1 on affected dairy farms and
identify additional sources of viral spread between cows and to humans. Surprisingly, we also
observed an HA mutation in a residue (H5 HA 189, H3 numbering 193) known to alter sialic acid
specificity26 in the air during milking of infected cows, suggesting that HA mutations are emerging
during this outbreak but are not currently maintained. Notably, mutations at 189 are associated
with improved binding to human a2,6-linked sialic acids26 and a structure of a 2.3.4.4b H5 with
an a2,6-linked sialic acid analog shows position 189 helps stabilize receptor binding24. Whether
the N189D mutation observed in this study alters receptor binding and improved tropism to
humans remains to be determined. These data support that emerging viral variants can pose a risk
to humans working in the dairy parlors through exposure to viruses in the air and on surfaces.

Given the high viral loads of H5N1 found in milk, milking equipment has been implicated
as the likely source for viral transmission. However, data from our longitudinal study revealed a
heterogeneous pattern of positivity across the subset of cows analyzed, both in the number and
location of positive quarters. If milking equipment alone was the driver of cow-to-cow H5N1
transmission it is likely that a similar pattern of positivity would have been observed between the
animals. Experimental transmission studies have also failed to induce H5N1 spread between cows
using contaminated milking equipment30. Thus, alternative mechanisms of transmission of H5N1
between cows must exist. The variations in H5N1 quarter positivity may reflect that, and animals
with all 4 quarters positive may be those with H5N1 viremia as reported in a subset of cows31.
While animals with fewer quarters H5 positive may have been from contaminated milking
equipment or infection in damaged teats that have encountered H5N1 virus through aerosols or
contaminated wastewater.

Surprisingly, we observed H5N1 positivity was not always associated with mastitis,
suggesting many subclinical infected cows on a farm whose milk will enter the commercial stream.
Assessment of mastitis-affected quarters in a distinct set of cows from the same farm done prior
to initiation of the longitudinal study identified a clear preference for the FR quarter. In contrast,
analysis of the five cows with only a single H5N1 positive quarter revealed two animals with a
positive FL quarter, one BL, one BR, and one FR. The lack of a consistent quarter infected across
all cows, as observed for mastitis, suggests that these two features are not linked and likely have
distinct modes of transmission.

While field surveillance is critical to understanding ongoing infectious disease outbreaks,
there are many limitations that are important to note when considering the data presented in this
manuscript. First, longitudinal sampling was conducted on a single farm with 14 cows over a short
period of time, which may have missed patterns that could be revealed with a larger number of
animals. Additionally, sampling across multiple farms, for longer periods of time, or earlier in an
outbreak may reveal different patterns. Constraints on time and personnel, shared milking
equipment could not be traced in our study, so patterns of the milking equipment usage and order
of milking for all 14 longitudinal animals are not known and likely varied each day of sampling
routes could include contaminated milking equipment from an infected cow, aerosols generated
within the milking parlor, and/or contact of teats with contaminated water used to clean housing
pens. Multiple mitigation strategies should therefore be implemented to reduce the risk of H5N1
spread within a herd and to humans. Respiratory and ocular personal protective equipment (PPE)
for farm workers to prevent deposition of virus-laden aerosols on these sites, especially in the
milking parlor. Disinfection of milking equipment between each milking of each cow, such as with
consistent use of backflush system, could also reduce spread of H5N1 between cows. Treatment
of milk from sick cows to inactivate H5N1 prior to disposal as well as treatment of waste streams
prior to their use on fields or on farms should also be considered. Finally, identification of infected
cows, regardless of clinical signs, for isolation will help reduce the transmission of H5N1 on farms.
routes could include contaminated milking equipment from an infected cow, aerosols generated
within the milking parlor, and/or contact of teats with contaminated water used to clean housing
pens. Multiple mitigation strategies should therefore be implemented to reduce the risk of H5N1
spread within a herd and to humans. Respiratory and ocular personal protective equipment (PPE)
for farm workers to prevent deposition of virus-laden aerosols on these sites, especially in the
milking parlor. Disinfection of milking equipment between each milking of each cow, such as with
consistent use of backflush system, could also reduce spread of H5N1 between cows. Treatment
of milk from sick cows to inactivate H5N1 prior to disposal as well as treatment of waste streams
prior to their use on fields or on farms should also be considered. Finally, identification of infected
cows, regardless of clinical signs, for isolation will help reduce the transmission of H5N1 on farms.
...
​

 

[sharon sanders]

Please see:

US H5N1 tracking forum link

US - Humans with full or partial test positive H5N1 results list (CDC + states + seropositive + assay positive)​

 

[Commonground]

[I'm looking for a date for this study, seems like the results have been known since early this year?]....


During the winter of 2024, five dairy farms in the Central Valley of California identified

as having HPAI H5N1 positive cows were enrolled in our initial air sampling studies

(Supplemental Table 1 and Figure 1A for general dairy farm layout). In the first phase of our study,

we compared a variety of air sampling strategies during the active outbreak on dairy farms to

define the optimal methodology that could be implemented in future sampling efforts. Aggregated

milk from cows, referred to as bulk tank milk, was tested frequently for the presence of H5N1 viral

RNA from late October 2024 until January 4, 2025 per federal recommendations 14

. The date that

each farm tested positive and first observation of clinical signs are depicted in Figure 1B. H5N1

was detected in bulk tanks on farms prior to the observation of clinically ill cows.

-snip-

Figure 1(B) Timeline of sampling during initial phase on dairy farms, including date the bulk tank tested positive, bulk tank status,

onset of clinical signs in cows, and sampling days numbered 1-5.


​
​https://www.biorxiv.org/content/10.1101/2025.07.31.666798v1.full.pdf

 

[Pathfinder]

​​

August 1, 2025: H5N1 Bird Flu in Livestock Updates


SACRAMENTO, CA — Following an investigation by the California Department of Food and Agriculture (CDFA) and rapid disease detection by California Animal Health and Food Safety Laboratory System (CAHFS), the U.S. Department of Agriculture's (USDA) National Veterinary Services Laboratories (NVSL) has confirmed 43 cases of H5N1 Influenza in California dairies that have been re-quarantined by CDFA after prior release. These are new detections on diaries that were infected previously but had their CDFA quarantine lifted after 3 negative whole herd tests via bulk milk tank samples, one week apart. These 43 farms have been shown to have sufficient virus present to be placed back under State Quarantine.

All dairies in the state continue to be under regular surveillance for continued monitoring of the virus in California.

Due to the increased number of re-infections in California dairies, the Ban on all California Poultry and Dairy Cattle Exhibitions at Shows and Fairs remains in place. Additional information can be found below this alert box.
​
...
https://www.cdfa.ca.gov/AHFSS/Animal_Health/HPAI.html

 

[Pathfinder]

Screenshots:

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...​

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...

https://www.cdc.gov/nwss/rv/wwd-h5.html

 

[Commonground]

[emphasis is mine]
September 9, 2025

More Data From Farms Could Help Scientists Better Track Avian Flu, but Privacy Concerns Stand in the Way
Government agencies have refused to disclose farm locations, precise outbreak dates and other metadata associated with poultry and cattle that test positive for avian flu.


For years, veterinary researcher Maurice Pitesky has run up against a roadblock while tracking the rapid spread of avian flu: a lack of public data. He has attempted to obtain — but has repeatedly been denied — state and federal data revealing the location of avian flu outbreaks on U.S. farms. It’s data he says could help inform predictive modeling to warn farmers about a higher risk of avian flu transmission near their property, giving them enough time to tighten biosecurity measures and potentially ward off an outbreak.

A national predictive surveillance system doesn’t exist yet, but Pitesky thinks it could be very feasible — if only he had access to more precise government data.

Data revealing the location and other information about the farms with animals that have contracted avian flu has generally been deemed confidential by state and federal government officials. The officials collecting this data do not make it publicly available under most circumstances, citing legal exemptions and agreements with agricultural businesses. The aim is often to protect farmers from economic losses, but in effect, Pitesky says, these decisions are a barrier for scientists scrambling to monitor the evolving, adaptable virus as it circulates in the U.S.

“The state and the feds have all that data about which farms are positive and which farms are negative,” Pitesky, an associate professor at the UC Davis School of Veterinary Medicine-Cooperative Extension, tells Sentient. “They’ve taken a good idea protecting farmer information to an illogical conclusion — in the sense that you basically have all that data siloed by just a few people who, at this stage, aren’t really doing very much research.”

Some of this data even originates at Pitesky’s own university. The California Animal Health and Food Safety Laboratory at UC Davis is the only lab in California equipped for high-risk avian flu testing in poultry and cattle — data that is reported to the public by the state and federal government, while stripped of data about the farms.

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The public data that exists on avian flu testing in animals is available on the websites of state agricultural departments and the U.S. Department of Agriculture (USDA), which maintains a public dashboard of H5N1 cases reported in the last 30 days. This includes the confirmed date of a positive test, the country and state of the outbreak and the type of farm business (such as live bird market, commercial turkey farm, etc.). But this testing data exists in a vacuum of other critical data points — it lacks contextual data, known as metadata, associated with each recorded avian flu outbreak.​

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For instance, on August 1st, California reported that 43 farms that had been previously infected reported new infections and were placed back under quarantine. But the federal data reflected a different story, revealing just one case reported on that day of avian flu in dairy herds in California. Depending on which dataset you’re looking at, you could have a very different understanding of avian flu infection levels.​

​continued: https://goodmenproject.com/featured...an-flu-but-privacy-concerns-stand-in-the-way/
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[Pathfinder]

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https://www.aphis.usda.gov/livestoc...an/avian-influenza/hpai-detections/wild-birds

 

[Commonground]

[emphasis is mine]

As avian influenza cases ramp up, experts caution the mixing of one flu with another
Sep 23, 2025

WEST FARGO, N.D. - Avian influenza activity has started to ramp up in North Dakota and South Dakota over recent weeks. Health experts in North Dakota are hoping to keep the public informed on what this virus is capable of.

Even as activity was nearly non-existent during the summer months across the upper Midwest, a partnership was built to enhance efforts around awareness and preparedness for highly pathogenic avian influenza in North Dakota. That partnership includes North Dakota State University Extension, NDSU Center for Immunization Research and Education , and North Dakota Department of Health and Human Services. They are focused on providing the public with accurate, timely information on the topic, as well as supporting poultry and dairy producers through outreach. It was made possible by a grant secured by the Health and Human Services Department to specifically focus on avian flu education.

The partnership made sense after 2024, one of the most severe seasons of influenza in North Dakota in almost a decade. North Dakota Department of Health and Human Services data shows there were 46 deaths associated with influenza in the state during the 2024-2025 season. That's the most in the last 16 years of data, which illustrates a very real need to reduce the risks posed to both animal and human health moving forward.
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https://www.redlakenationnews.com/s...he-mixing-of-one-flu-with-another/134757.html

 

[Commonground]

Half million Bird Flu cases now in the region: ND, SD, MN, MT

​Sep 23, 2025​

BISMARCK, ND (KXNET) — The USDA has confirmed more than 500,000 cases of avian influenza across North Dakota, South Dakota, Montana, and Minnesota.

North Dakota has two counties with confirmed cases. 60,000 cases were found at a commercial turkey flock in Dickey County, which KX News previously reported.
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continued: https://www.kxnet.com/news/north-dakota-turkey-cases/