Washington: Yakima County Reports 2nd Human H5N1 Case (Hospitalized with severe illness)

 

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Yakima County, Washington is now reporting their second human infection with H5N1 associated with their ongoing (and rapidly expanding) outbreak in dairy cattle.  

Worth noting: While `bovine' B3.13 H5N1 infection has generally been associated with mild illness in humans, this case is reportedly hospitalized with severe illness.  

This patient is described as having unspecified `underlying health conditions', and of course, we don't as yet have official confirmation of the genotype (presumably B3.13).

First the press release, after which I'll have a bit more.

For immediate release: October 31, 2026

Contact: Stephanie Ruiz, Communications Specialist (509) 941-7364

Second Yakima County Resident Tests Positive for Avian Influenza

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.

(Continue  . . . )

Those who work with poultry, wild birds, or dairy cattle are presumed to be at greatest risk of exposure to avian flu, but other exposures (dogs, cats, other peridomestic animals) are possible.  

There are also a handful of cases here in the United States where no known exposure was identified. 

 

For people at the highest risk, the CDC continues to recommend the use of PPEs (see below).  

In early October we looked at: 

AVMA: How can veterinary personnel recognize and protect themselves from domestic cats infected with HPAI A(H5N1) viruses?

And the CDC offers the following advice to pet owners on how they may keep their animals safe from avian flu, and what to do if they suspect infection.

While the risk to the general public is still presumed to be low, it is not zero.  

Since every human infection is another opportunity for the virus to adapt, the steps we take today to reduce human exposure could conceivably lower future risks from the virus. 

But for that to happen, people need to take the threat seriously.

Colorado Reports 1st H5N1 In Dairy Samples Since 2024 - Washington State adds 4 more Infected Herds

 

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Just 24 hours ago I reported that Washington State had added 3 More Dairy Herds Infected with H5N1 (n=30), but yesterday the WSDA added 4 more herds to their rapidly expanding list. 

Meanwhile, Colorado - which was one of the earliest affected states back in 2024 - is reporting its first detection in bulk milk in almost 2 years. The following press release was published yesterday by Colorado's Department of Agriculture.

Routine Milk Tank Testing Detects Colorado's First Dairy HPAI Case Since 2024

Friday, October 30, 2026 

The risk to the general public is low and pasteurized milk continues to be safe because pasteurization kills viruses

The U.S. Department of Agriculture’s National Veterinary Services Laboratory (NVSL) has confirmed a detection of Highly Pathogenic Avian Influenza (HPAI) in a dairy in Weld County. This is the first HPAI detection in a Colorado dairy since August 2024. Since the initial detection of HPAI in dairy cattle in April 2024, Colorado has implemented routine bulk milk tank surveillance testing to ensure Colorado’s milk supply is not impacted.

“This detection underscores the importance of our routine bulk milk tank testing to keep our herds healthy and our food supply secure,” said Colorado State Veterinarian Dr. Maggie Baldwin. “Colorado has taken a proactive approach to monitoring and responding to avian influenza, ensuring that early detection leads to swift mitigation measures to protect consumers and our food supply.”

The Colorado State Veterinarian’s Office was notified by the Colorado State University Veterinary Diagnostic Laboratory that a sample from a routine bulk milk tank test tested presumptive positive for HPAI. The National Veterinary Services Laboratory (NVSL) issued the official confirmation of the detection of HPAI (B3.13 strain) in a dairy in Weld county on Saturday, October 24. The dairy has been put under a quarantine order.

Under the quarantine order, several mandatory stipulations are in effect to prevent further transmission of the virus. The quarantine restricts the movement of lactating dairy cattle from the affected facility. In addition, the operation must immediately implement strict biosecurity protocols across all farm activities and daily routines. To monitor and verify disease status, weekly bulk milk tank testing is required until two consecutive negative test results are obtained at least one week apart.

CDA is working closely with the Colorado Department of Public Health and Environment and local partners to protect the health of farmworkers and facility staff. Public health officials routinely monitor individuals following potential exposure to infected animals or raw animal products as a standard precaution. People most at risk for avian flu are those who come directly into contact with infected birds or other animals. The risk to the general public remains low and pasteurized milk continues to be safe, because pasteurization kills viruses.

Colorado originally confirmed its first positive detection of HPAI in dairy cattle on April 25, 2024, during an outbreak that grew to affect 64 individual dairies across the state. In response to the widespread outbreak, Colorado became the first state in the nation to institute mandatory bulk milk tank testing for all commercial dairies in Colorado. That comprehensive monitoring effort successfully cleared all affected herds, with all dairies released from quarantine by December 2024.

Colorado was rightfully applauded back in 2024 for their aggressive response to their initial outbreak (n=64 herds) (see Colorado Orders Mandatory Statewide Weekly Bulk-Tank Testing for HPAI), which was copied by many states. 

It will be of considerable interest to learn exactly how this new case came about, and whether this is a one-off event. 

In Washington state, the big questions are what is driving the spread of the virus, and how long it may have been going on before it was detected.  

Until we have answers to those questions, it is impossible to know whether these events are unrelated occurrences or the start of a new trend. 

Stay tuned. 

 

Washington State Reports 3 More Dairy Herds Infected with H5N1 (n=30)

 

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In just 3 weeks the State of Washington has gone from never reporting H5N1 in dairy cattle, to reporting 30 infected herds. Twelve days ago they also reported a (mildly) infected dairy worker was recovering at home. 

Thus far, we've no information on how the virus (identified as B3.13) is spreading from farm to farm.

While Washington State is the current hotspot for reported H5N1 in dairy cattle, over the past month two other states - Texas and Kansas - have reported outbreaks. 

 

As we discussed yesterday in Preprint: Why Americans Choose Raw Milk: Evidence from a National Quantitative Survey - while Washington State warns against the consumption of raw milk, it also allows its sale in grocery stores. 

Hopefully people are paying attention, not only to these outbreaks, but to the labels on the milk and milk-products they buy and consume. 

Hawaii DOH Reports H5N1 Genotype D1.1 in Wastewater on Kauaʻi

Hawaii lies beneath the West Pacific Flyway

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In November of 2024 the state of Hawaii reported their first ever detections of HPAI H5N1, first in a wastewater sample on Oahu, followed by two outbreaks in captive and/or wild birds the following week. Subsequent detections were made in wastewater on the big island, in Hilo in December 2024, and at the Wastewater Treatment Plant on Kauaʻi in January 2025.

Proving this all wasn't just a fluke, in the fall of 2025 we saw at least 3 more detections.  While concerning, none of these outbreaks involved the B3.13 `bovine' or D1.1 poultry/wild bird strains, which together had caused scores of human infections in the United Stats. 

Today, however, we have the first detection of H5N1 genotype D1.1, again from a wastewater plant, this time on the island of Kauaʻi. This was an environmental sample from an unknown source, and does not establish an infectious virus, a human case, or community transmission.  

First the DOH statement, after which I'll have more. 

DOH REPORTS H5N1 AVIAN FLU DETECTED IN KAUAʻI COUNTY WASTEWATER SAMPLE

Posted on Oct 29, 2026 in Newsroom

HONOLULU — The Hawaiʻi State Department of Health (DOH) is reporting that a wastewater sample from Kauaʻi County tested positive for H5N1 avian influenza. The sample was collected at a site in East Kauaʻi on Oct. 14, 2026. DOH was notified of the result on Oct. 26. This is the first detection of the H5N1 virus associated with this year’s seasonal bird migration and the first detection of genotype D1.1 in Hawaiʻi.

In the United States, genotype D1.1 has become the predominant genotype in infected wildlife and domestic poultry and there have also been isolated events of D1.1 infecting dairy cattle. DOH continues to test milk from the local dairy and there have been no detections of H5N1. A small number of human cases of genotype D1.1 have been reported nationally. Human cases of avian flu are rare, and most cases have not caused severe illness. No human-to-human transmission of H5N1 has been reported. Genotype A3 was the strain previously detected in Hawaiʻi.

“While the risk to the public remains low, avian influenza can cause severe illness and high mortality among certain bird populations, including poultry,” said Deputy State Epidemiologist, Dr. Nathan Tan..“Commercial poultry producers and residents with backyard flocks are strongly advised to increase biosecurity measures to reduce the risk of infection. Avian influenza can also infect dairy cows and while pasteurized milk is safe to consume, raw milk should be avoided.”

For the municipal wastewater sample collected on Oct. 14 by Kauaʻi County, digital polymerase chain reaction (dPCR) testing did not detect H5 avian influenza. However, genomic sequencing identified genetic material from H5N1 avian influenza genotype D1.1. The difference in results is not unusual: dPCR tests for specific genetic targets, while sequencing can identify genetic material present in very small amounts. A subsequent sample collected on Oct. 21 tested negative for H5 avian influenza by dPCR; genomic sequencing results for that sample are still being processed.

It is important to note that the detection of H5 genetic material in wastewater does not mean that live, infectious virus is present. Wastewater testing also cannot determine whether the source of the genetic material is animal, human or environmental contamination. An H5 signal does not confirm a clinical case or indicate community transmission. Instead, it serves as an early indicator that can prompt increased awareness and monitoring. The East Kauaʻi wastewater treatment plant is an open system, meaning the detection could be associated with a variety of sources, including contaminated products or waste from infected animals or people.

Wastewater sampling is routinely conducted across Hawaiʻi to support infectious disease surveillance. Samples are sent to the DOH State Laboratories Division (SLD) for dPCR testing, as well as to the University of Missouri for advanced genomic sequencing to identify bacterial and viral genetic material associated with community infections. Using both methods provides complementary information and strengthens Hawaiʻi’s ability to detect low-level signals in wastewater. In addition to SLD’s testing, H5 avian influenza is monitored in other Hawaiʻi counties through the National Wastewater Surveillance System (NWSS) and WastewaterSCAN.

The Hawaiʻi Department of Agriculture and Biosecurity (HDAB) recommends the following precautions for residents who need to remove a dead wild bird from their property:

• Wear disposable gloves or turn a plastic bag inside out and use it to pick up the carcass.
• Double-bag the carcass and dispose of it with regular trash.
• Wash your hands and disinfect your clothing and shoes after handling a dead wild bird.
• Monitor for any health symptoms that may develop afterward.

To report multiple or unusual illnesses in poultry, livestock or other wild birds or animals on any island in the state, contact HDAB’s Animal Industry Division at 808-483-7100 or email hdoa.ldc@hawaii.gov, Monday through Friday, from 7:45 a.m. to 4:30 p.m. For reports outside business hours or on holidays, call 808-837-8092.

Residents who believe they may have been exposed to sick birds or other wildlife should contact the DOH Disease Outbreak Control Division’s Disease Reporting Line at 808-586-4586 for additional guidance.

Roughly 5 months after the first outbreak, Hawaii's DOH Launched a Bird Flu Survey For Backyard Flock Owners & Bird Rescuers, whose findings were published over the summer of 2025.  

The survey was restricted to local residents aged 18 years or older who either keep birds at home, perform animal rescue, or engage in other bird-related activities.

As the following excerpt from the Hawaii DOH press release indicates, there were significant gaps in the understanding of bird flu risks, and best practices, among these high-risk cohorts. 

FINDINGS FROM DOH BIRD FLU SURVEY FOR BACKYARD FLOCK OWNERS AND BIRD RESCUERS

Posted on Jul 24, 2025 in Newsroom

HONOLULU — A survey by the Hawaiʻi State Department of Health (DOH) finds that while most local residents are aware that the bird flu had been detected in Hawai‘i, roughly two-thirds of flock owners had been unaware of related best practices.

In March 2025, the Hawaiʻi State Department of Health (DOH) invited Hawaiʻi residents who keep backyard flocks or are involved in bird rescue to participate in a survey aimed at gathering important data on bird flu awareness and preparedness.

The anonymous, online survey collected information on the understanding of bird flu, as well as the practices and needs of those who keep poultry or care for rescued birds.

Among the findings:

• About two-thirds of backyard flock owners across the state reported they were not at all familiar with the U.S. Department of Agriculture’s Defend the Flock recommended practices to prevent bird flu.
• Two-thirds of survey respondents also reported not knowing how to properly and safely remove and dispose of dead birds.
• Most respondents (84%) were aware that bird flu had been detected in Hawaiʻi, and of the H5N1 variant that causes the flu.
• Most respondents (72%) said they were very or somewhat concerned about the bird flu.
• The top source of health information for the majority (76%) of Hawaiʻi residents is their doctor, which they ranked as very or somewhat trustworthy.

             (Continue . . . )

Regardless of happens next in Hawaii, the USDA's dashboard (below) indicates, this fall's avian flu season is already off to a vigorous start, with more than 2.5 million birds affected over the past 30 days.

The threat from H5N1 has grown markedly in the Western Hemisphere since 2022. Things we used to do without much thought - like raising a few chickens the backyard - carry more risks today. 

While most commercial poultry producers have experience dealing with outbreaks, surveys indicate that backyard producers are generally less well aware of the signs of avian flu, and may be less inclined to wear PPE.  

Which means, if you raise backyard birds, now would be a good time to familiarize yourselves with the risks of avian flu, and the things you can do to reduce those risks to you and your families.

UF/IFAS Extension: What Backyard Flock Owners Need to Know about Bird Flu (Influenza H5N1)

CDC Guidance Backyard Flock Owners and Bird Flu 

 

Preprint: Why Americans Choose Raw Milk: Evidence from a National Quantitative Survey

 

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With reports of H5N1 infected dairy herds increasing again (see Washington State: H5N1 Detections in Cattle Triple (n=27) - 2nd County (Benton) Affected), we are seeing an uptick in warnings from health departments about the dangers of consuming raw milk. 

The King County, WA Dept. of Public Health unambiguously warns:

Raw (unpasteurized) milk and raw milk products

Consuming raw milk and raw milk products can pose health risks.
Raw milk and A(H5N1) virus‎

The CDC recommends against consuming raw milk contaminated with live A(H5N1) virus as a way to develop antibodies against A(H5N1) virus to protect against future disease. Consuming raw milk could make you sick.
 
Why is raw milk unsafe?

• Raw milk is milk from animals, typically cows and goats, which has not been pasteurized. Pasteurization is a process of heating raw milk to kill germs from the animal that are present in the raw milk.
• Some people believe that raw milk is more nutritious than pasteurized milk; however, the major nutrients in milk are not affected by pasteurization.
• Raw milk and raw milk products, such as cream, cheese and yogurt can be contaminated with harmful bacteria and cause serious infections.
• People with weakened immune systems, young children, the elderly, and pregnant women are at increased risk for severe infections from raw milk and milk products. It is especially important that young children, elderly persons, and persons with weakened immune systems consume only pasteurized milk and milk products.
• Read the label! In Washington state, it is legal to sell raw milk but raw milk products must be clearly labeled.

In the fall of 2024, we saw similar warnings after a number of household pets were infected with H5N1, some presumably from exposure to raw milk and/or raw pet food (see LA County Issues Another Raw Milk Warning).

Despite ample evidence of its dangers, most states allow its sale from farms or co-ops, and some states - like Washington - allow it to be sold in grocery stores alongside pasteurized milk.

                            State Laws on sale of raw milk - Credit CDC

A 2022 study published in the Journal of Food Protection found that:

Results show that 4.4% of U.S. adults reported consuming raw milk at least once in the past year, with 1.6% reporting frequent consumption of raw milk (once per month or more often) and 1.0% reporting consumption once per week or more often.

Today we have a new preprint - published Oct 28th - which suggests Americans' consumption of raw milk may be even higher than previously reported. 

It is based on a survey of 1,075 eligible US adults through an online panel in February of 2025, and it reports roughly 15% of US adults consumed raw milk in the preceding six months.

While it is possible that pro-raw-milk enthusiasts were more likely to respond to this survey, recruitment was done through Qualtrics Research Services - using demographic quotas - not an openly advertised public poll. 

I've posted the abstract below, but those wishing a deeper dive will want to follow the link to read the preprint in its entirety.

Why Americans Choose Raw Milk: Evidence from a National Quantitative Survey
Sophia Ruser, Cristina Rojo, Katherine J Koebel,  Calvin Slaughter,  Ece Bulut,  Renata Ivanek
doi: https://doi.org/10.64898/2026.10.26.26366487
This article is a preprint and has not been certified by peer review 
 
Preview PDF

Abstract

Raw milk consumption is a controllable source of foodborne pathogen exposure in the United States (US), yet existing national estimates of raw milk consumption behaviors are outdated and do not capture emerging factors such as consumers' trusted information sources, sociopolitical influences, and at-home risk mitigation behaviors.

We conducted a nationally representative cross-sectional survey of n=1078 US adults to estimate the prevalence of raw milk consumption and at-home thermal treatment practices and identify predictors of these behaviors. Multivariable logistic regression models were used to evaluate predictors of raw milk consumption and thermal treatment behavior using adjusted odds ratios (aORs).

Among 1,075 eligible respondents, 15% consumed raw milk in the last six months, including 5% exclusively and 10% in addition to pasteurized milk. 

In multivariable analysis, raw milk consumption was independently associated with younger age, cohabitation with high-risk individuals for foodborne infections (including children less than or equal to five years of age, and elderly, pregnant or immunocompromised individuals) who had consumed raw milk, and perceptions of raw milk taste and safety. 

Adults aged greater than or equal to 55 years had lower odds of consumption than those aged 18-24 years (aOR, 0.05; 95% CI, 0.02-0.15), while those living with a high-risk household member who consumed raw milk had higher odds of consumption (aOR, 4.39; 95% CI, 2.69-7.22). Perceiving raw milk to have higher risk of causing illness was associated with lower odds of raw milk consumption (aOR: 0.32, 95% CI: 0.17-0.62) compared to believing the risk to be equal across milk types, and thermal treatment was reported by 38% of exclusive raw milk consumers (n=58) and 47% of consumers of both milk types (n=106).

Raw milk consumption in the US appears to be substantially more common than previously reported and shaped by factors such as taste, safety, and household raw milk consumption among high-risk individuals for foodborne infections. The proportion of raw milk consumers already practicing at-home thermal treatment suggests a potential opportunity for risk mitigation.

While all of this is self-reported and unverified information, it appears that among the respondents to this poll that high-risk groups (young children, elderly persons, and persons with weakened immune systems) are often cited as household consumers of raw milk.

• 10.0% reported a child aged five or younger who had consumed it.
• 9.1% reported an adult aged 65 or older.
• 3.2% reported an immunocompromised person.
• 2.1% reported a pregnant person.

One potential bright spot, however, is the reported practice of heating or steaming raw milk (44% reported doing so > 50% of the time). Whether their heating temperatures and times were sufficient to kill pathogens is unknown.

Since we've seen multiple instances where H5N1 contaminated raw milk has reached store shelves (see California: CDFA Announces Another Recall of H5 Contaminated Raw Milk), the risks - while low - are genuine. 

But whether any of this will dissuade those currently inclined to consume raw milk - after decades of near universal public health advice to the contrary - remains to be seen.

WHO: Fatal H1N1v Infection In Brazil

 

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Overnight the World Health Organization published its latest Influenza at the human-animal interface summary and assessment, 7 October 2026, which describes one previously reported  H5N1 case from Cambodia, 4 recent H9N2 cases reported from Mainland China, and one fatal H1N1v case from Brazil.

The H1N1v case is unusual in that the adult female patient - who had (unspecified) pre-existing chronic conditions - died after a month-long hospitalization. Of note:  Her husband and three adult children also reported flu-like symptoms - were treated for a `viral infection' - but were never tested. 

According to the timeline provided by this report, the hospitalized case was only identified as having a novel flu (H1N1v) a week after her death.  As a result, epidemiological investigation wasn't begun until September 5th, roughly 7 weeks after she (and her family) first fell ill.

First, the WHO report, after which I'll return with more.

Swine influenza viruses in humans 

Influenza A(H1N1)v, Brazil

On 30 September 2026, Brazil notified PAHO/WHO of a laboratory-confirmed human infection with an influenza A(H1N1)v virus in an adult woman, with pre-existing chronic conditions, residing in the state of Santa Catarina. She developed symptoms of influenza-like illness on 16 July 2026 and sought medical attention on 20 July. 

Her husband and three adult children, who live in the same household,also experienced symptoms of an influenza-like illness; at that time, all were diagnosed, based solely on clinical examination, with a viral infection and received treatment.

  The woman, however, did not recover. On 27 July, the patient was hospitalized due to worsening respiratory symptoms. She received treatment, including the antiviral oseltamivir, and required intensive care, including ventilatory support. Despite intensive care, the patient passed away on 28 August.

A nasopharyngeal sample, collected on 29 July, tested positive for influenza A on 30 July and was subsequently subtyped as influenza A(H1N1) on 31 July. The sample was sent to the reference laboratory for respiratory viruses at the Oswaldo Cruz Institute (IOC/Fiocruz) in Rio de Janeiro for further characterization. On 4 September, genomic analysis identified an influenza A(H1N1)v virus.

According to information gathered during an epidemiological investigation conducted by municipal and state teams between 5 and 9 September, the patient had no history of travel or direct contact with swine. However, a possible indirect exposure to swine was identified through a neighbour who raises these animals for personal consumption.

Since 2015, twelve cases of human infection with swine-origin virus variants, including this one, have been detected within Brazil’s respiratory virus surveillance workflow.

This chronology illustrates just how difficult it can be to detect a novel virus, even when the patient is hospitalized with severe influenza. A few recent examples include:

• In November of 2025, Washington State reported the first known human infection with avian H5N5; a diagnosis that was delayed - according to an MMWR report - by  `early and repeated negative influenza test results from upper respiratory swab specimens'.

• In 2024, a Missouri patient was hospitalized with influenza A, and released, before being notified they had H5N1 (see Missouri DHSS: Human H5 bird flu case confirmed in Missouri). 

• Also in 2024, Australia treated a child with recent travel from India for severe flu, which resulted in respiratory failure. The child fell ill (in India) in late February, was hospitalized in Melbourne in early March, and was released after > 2 weeks. While respiratory samples were taken in early March, they weren't identified as H5N1 positive until mid-May.  

Complicating matters, most people experiencing mild or moderate flu symptoms are unlikely to seek medical care, and even when they do, they are often treated for a `viral illness' and never tested.  

We've seen past studies (see here, here, and here) suggesting that as few as 1 in 100 cases are identified in the community. 

In early 2025, the CDC issued a HAN: Accelerated Subtyping of Influenza A in Hospitalized Patients, requesting that all hospitalized patients with suspected influenza be subtyped within 24 hours. 

More recently, we saw Washington State: Updated guidance for novel influenza screening and influenza subtyping, which emphasized the importance of identifying those with acute respiratory illness (ARI) and specific epidemiologic risk factors.

The reality is, it takes a certain degree of luck to detect sporadic novel flu infections in the community. While better screening methods could improve detection rates, many mild and moderate infections will still likely fly beneath our radar. 

A reminder than anything we say about the current threat from H5N1, swine flu variants, MERS-CoV, or any other pandemic threat must carry an implied asterisk.

A disclaimer that says, ` * based on available, and likely incomplete, information. . . '.