Sophie Zhu, PhD1,2; Kathleen Harriman, PhD2; Caterina Liu, MD2; Vit Kraushaar, MD2; Cora Hoover, MD2; Kyoo Shim, MPH2; Sharon I. Brummitt, PhD2; Jocelyn Limas, MPH2; Kathleen Garvey, MHS2; Jennifer McNary, MPH2; Nina J. Gao, PhD2; Rahil Ryder, MS2; Brandon Stavig2; Jeffrey Schapiro, MD2; Christina Morales, PhD2; Debra A. Wadford, PhD2; Holly Howard, MPH2; James Heffelfinger, MD2; Rebecca Campagna, DVM2; Esmeralda Iniguez-Stevens, PhD2; Hamed Gharibi, PhD2; Denise Lopez, DrPH3; Laura Esbenshade3; Paula Ptomey3; Kavita Okay. Trivedi, MD4; Jade A. Herrera4; Joanna Locke, MD4; Nicholas Moss, MD4; Paul Rzucidlo, MPH5; Kimberly Hernandez, MPH5; Minhphuong Nguyen, MPH6; Simon Paul, MD6; Justin Mateo, MPH7; Carlos Del Carmen Luna7; Yer Chang7; Maria Rangel8; Keiryl DeLeon9; Aisha Masood9; Thea Papasozomenos, MD10; Payeng Moua10; Katie Reinhart, PhD11; Krista Kniss, MPH11; C. Todd Davis, PhD11; Marie Okay. Kirby, PhD11; Erica Pan, MD2; Erin L. Murray, PhD2; Los Angeles County H5 Reaction Staff; California Division of Public Well being H5 Laboratory Reaction Staff (View writer affiliations)
View advised citationSummary
What’s already identified about this subject?
Individuals with occupational publicity to extremely pathogenic avian influenza (HPAI) A(H5N1) virus–inflamed dairy farm animals are at larger possibility for an infection.
What’s added by means of this document?
All the way through September 30–December 24, 2024, a complete of 38 individuals gained a good take a look at end result for HPAI A(H5N1) viruses in California; 37 have been dairy farm employees with occupational publicity to unwell cows. One, an individual elderly <18 years with an undetermined publicity, was once the primary pediatric affected person detected with influenza A(H5) an infection in the US.
What are the consequences for public well being follow?
Public well being companies must examine influenza-like sickness or conjunctivitis in employees with occupational publicity to animals inflamed with HPAI A(H5N1) virus. Thorough investigations of all human HPAI A(H5N1) virus infections are essential to spot attainable publicity assets, together with tracking the virus for regarding genetic adjustments that point out the possibility of person-to-person transmission.
Summary
Individuals who paintings carefully with dairy cows, poultry, or different animals with suspected or showed an infection with extremely pathogenic avian influenza (HPAI) A(H5N1) viruses are at larger possibility for an infection. In September 2024, the California Division of Public Well being was once notified of the primary human case of HPAI A(H5N1) in California via tracking of employees on farms with inflamed cows. All the way through September 30–December 24, 2024, a complete of 38 individuals gained sure take a look at effects for HPAI A(H5N1) viruses in California; 37 have been dairy farm employees with occupational publicity to unwell cows, and one was once a kid elderly <18 years with an undetermined publicity, the primary pediatric HPAI A(H5N1) case reported in the US. All sufferers had delicate sickness. The identity of circumstances related to occupational publicity to HPAI A(H5N1) viruses on dairy farms highlights the continuing possibility for individuals who paintings with inflamed animals. The pediatric case was once recognized via regimen surveillance. Given fresh will increase within the incidence of HPAI A(H5N1) viruses amongst some animal populations, public well being companies must proceed to research circumstances of HPAI A(H5N1) in people as a part of keep watch over measures, pandemic preparedness, to spot regarding genetic adjustments, and to stop and discover attainable human-to-human transmission of the virus. Thus far, no human-to-human transmission of HPAI A(H5N1) virus has been recognized in the US.
Creation
Novel influenza A pandemic an infection, together with extremely pathogenic avian influenza (HPAI) A(H5N1) virus, is a reportable situation in California and nationally reportable to CDC.* In 2024, the California Division of Public Well being (CDPH), California Division of Meals and Agriculture (CDFA), native well being departments (LHDs), and farms identified to be suffering from HPAI A(H5N1) (i.e., dairy or poultry farms with nonnegative [positive or inconclusive] A(H5) take a look at effects for cows, bulk milk, or poultry) coordinated to cut back an infection possibility and observe HPAI A(H5N1) signs† amongst employees. All farm homeowners or managers of affected farms have been recommended to habits day by day tracking of employees and document signs in line with HPAI A(H5N1) an infection in employees who have been in touch with affected animals to their LHD. When farm homeowners didn’t volunteer to do the tracking, the LHD presented to accomplish tracking of signs without delay with employees via telephone calls or textual content messaging. Symptomatic employees have been referred for specimen assortment, generally, conjunctival, nasal, nasopharyngeal, or oropharyngeal swabbing, according to symptom presentation. Focused surveillance, which incorporates influenza typing and subtyping for A(H5), was once carried out at both a neighborhood or the state public well being laboratory (PHL) for all symptomatic employees or individuals with epidemiologic linkage (1) to HPAI A(H5N1) reported to public well being officers. PHLs use the CDC Human Influenza A Subtyping Equipment which detects and differentiates hemagglutinin (H) proteins as a part of regimen influenza surveillance. Decided on native PHLs make use of the CDC Influenza A(H5) Subtyping Equipment to discover A(H5)§ Asian lineage viruses for suspected HPAI A(H5N1) circumstances. Presumptive sure or inconclusive A(H5) specimens have been despatched to CDC for confirmatory trying out. This document summarizes data on human HPAI A(H5N1) circumstances recognized in California all the way through September 30–December 24, 2024.
Investigation and Effects
Preliminary Public Well being Notification and Reaction
On August 30, 2024, CDFA detected, and the Nationwide Veterinary Services and products Laboratories due to this fact showed, HPAI A(H5N1) virus infections in cows from 3 dairy farms within the Central Valley area of California. In September 2024, CDPH was once notified of the primary human case of HPAI A(H5N1) in California via tracking of employees on farms with inflamed cows. On October 3, 2024, the primary two human HPAI A(H5N1) circumstances in California have been showed in employees on two separate farms the place inflamed cows have been detected in September. Those sufferers have been recognized and reported by means of their employers to their LHD; each had conjunctivitis, and one additionally had a fever. Specimens from each sufferers examined sure for influenza A(H5) virus at a neighborhood PHL and have been showed as HPAI A(H5N1) at CDC. LHD group of workers contributors equipped steering on isolation and presented the antiviral oseltamivir to sufferers and their family contributors. No identified epidemiologic hyperlinks existed between the 2 sufferers.
As of December 24, 2024, the U.S. Division of Agriculture reported 675¶ dairy herds with inflamed cows, 92 business flocks with inflamed poultry,** and 35 yard flocks with inflamed poultry in California. All the way through August 30–December 24, a complete of five,126 employees have been monitored at affected farms; 170 individuals from 19 native well being jurisdictions gained trying out for influenza A(H5) via centered surveillance. One further affected person was once reported via regimen surveillance and due to this fact gained trying out at a PHL. Of the 171 individuals who gained trying out, CDPH recognized 36 showed circumstances and one possible (1) case of HPAI A(H5N1) amongst grownup dairy farm employees and one showed case in a kid elderly <18 years with out dairy cow or poultry publicity; 37 individuals gained sure take a look at effects showed at CDC. This job was once reviewed by means of CDC and CDPH, deemed analysis no longer involving human topics, and was once carried out in line with appropriate federal legislation and CDC coverage.††
Description of Human HPAI A(H5) Instances
Human circumstances with publicity to dairy cows (37). Individuals with HPAI A(H5N1) an infection (36 showed and one possible) labored at 29 distinctive dairy farms (Desk 1). The median period from first A(H5) virus detection in cows to the primary human case on a specific farm was once 7 days (vary = −7 to twenty days). Employee tracking was once initiated on one unaffected farm as a result of A(H5) virus have been detected in cows on different dairy farms owned by means of the similar consumer. All sufferers with occupational publicity to dairy cows have been elderly 18–64 years (Desk 2). Six sufferers reported underlying clinical prerequisites. A majority (76%) labored as milkers or cared for unwell cows. A majority of sufferers (78%) reported the use of non-public protecting apparatus (PPE) at paintings; 25 (68%) wore gloves, 20 (54%) used eye coverage (13 reported dressed in goggles), 12 (32%) reported dressed in boots, and 6 (16%) wore robes. No sufferers in particular reported dressed in a respirator (e.g., an N95 masks) as beneficial§§; then again, 12 (32%) reported dressed in different face coverings or face mask.
Sufferers gained trying out a mean of two days (vary = 0–5 days) after symptom onset. All sufferers had delicate sickness. Ceaselessly reported indicators and signs integrated eye inflammation or redness (97%), muscle aches (34%), and fever (29%). Respiration signs, together with sore throat (16%) and shortness of breath (11%) have been much less often reported. No hospitalizations or deaths took place, and all sufferers recovered. All 37 sufferers have been presented oseltamivir; two declined (5%). No circumstances have been recognized in family contacts of sufferers with occupational publicity.
Undetermined publicity supply (one). One showed case was once detected via regimen influenza surveillance in a prior to now wholesome kid who had no identified touch with inflamed animals or people and had no longer fed on unpasteurized dairy merchandise. This affected person, who had delicate breathing signs and otitis media however no conjunctivitis, was once no longer hospitalized. Oseltamivir was once prescribed when sure take a look at effects have been gained for influenza A pandemic. Subtyping was once sure for influenza A(H5) virus.¶¶ The affected person’s 3 family contributors additionally had breathing signs; one evolved signs an afternoon sooner than the affected person, whilst the 2 different contributors evolved signs at the same time as. 4 days after the affected person’s preliminary trying out, breathing specimens have been accrued from all family contributors. All specimens examined unfavourable for influenza A(H5) virus. Specimens from the affected person and two family contributors examined sure for adenovirus and rhinovirus.
Laboratory effects (38). Thirty-five (95%; 37) sufferers gained a good conjunctival swab end result, 8 (28%; 29) sufferers gained sure take a look at effects for mixed nasal and oropharyngeal swabs, 5 (14%; 37) sufferers gained sure nasopharyngeal swab take a look at effects, two (33%; 6) sufferers gained sure nasal swab effects, and one (25%; 4) affected person gained a good oropharyngeal swab end result (Desk 2). Nearly all of sufferers had both a good conjunctival or mixed nasal/oropharyngeal swab (97%). One affected person best gained a good nasal swab end result and not using a different sure websites.
Genetic Sequencing
Genetic sequencing of the viruses was once carried out from scientific specimens of 30 sufferers; all have been recognized as HPAI A(H5N1) clade 2.3.4.4b viruses. All 8 gene segments of the viruses have been recovered from 16 sufferers, and partial gene segments have been recovered from the opposite 14. The viruses from the 16 sufferers with all gene segments sequenced (Determine) have been recognized as HPAI A(H5N1) clade 2.3.4.4b, genotype B3.13. The pediatric affected person (A/California/192/2024) best had 5 of 8 segments sequenced, which was once inadequate to categorise a selected genotype; then again, the neuraminidase and nucleoprotein sequences shared shut genetic identification to fresh California HPAI A(H5N1) B3.13 genotype viruses from people, dairy farm animals, and poultry. One virus (A/California/150/2024) contained a nucleotide substitution inside the polymerase acidic gene (I38M), which is related to lowered susceptibility to the antiviral baloxavir marboxil.*** No substitutions related to lowered oseltamivir susceptibility or diversifications for environment friendly human-to-human transmission have been detected.
Dialogue
This document describes investigations that resulted in identity of 38 individuals who gained sure take a look at effects for HPAI A(H5N1) viruses in California; 37 have been dairy farm employees with occupational publicity to unwell cows, and one was once a kid elderly <18 years with an undetermined publicity. Epidemiologic and scientific traits have been very similar to the ones in different U.S. human circumstances (2,3). In genetic sequencing of 30 of the 38 inflamed sufferers, all have been recognized as HPAI A(H5N1) clade 2.3.4.4b viruses. A substitution related to lowered baloxavir susceptibility was once recognized in a single virus sequenced from a human case in California. No further regarding substitutions have been recognized.
The identity of 37 circumstances with occupational publicity throughout 29 dairy farms highlights the continuing possibility for cow-to-human transmission of HPAI A(H5N1) viruses amongst individuals who’ve shut touch with inflamed cows and their uncooked milk (4). The absence of circumstances amongst family contacts is in line with the absence of viral genetic markers for environment friendly human-to-human transmission.
Even though a majority of sufferers reported the use of PPE at paintings, use of beneficial PPE (i.e., N95 respirators as opposed to face masks) has been prior to now reported as being low amongst dairy farm employees with HPAI an infection (5). Further schooling and messaging concerning the dangers of operating with inflamed cows and making sure employee get admission to to PPE would possibly build up PPE use, in particular if achieved in collaboration with farm employee organizations and manufacturers.
This document describes the primary detection of a pediatric case of influenza HPAI A(H5N1) in the US. The supply of this kid’s an infection stays undetermined. In contrast to pediatric sufferers with HPAI A(H5N1) virus infections in different nations who had serious sickness (6,7), this kid had best delicate breathing signs and recovered temporarily. Different sporadic circumstances of influenza HPAI A(H5N1) have took place in individuals and not using a identified publicity to doubtlessly inflamed animals (8). Thus far, human-to-human transmission of HPAI A(H5N1) viruses has no longer been recognized in the US.†††
Boundaries
The findings on this document are matter to no less than 3 obstacles. First, details about the kind of and share of time that PPE was once worn was once unavailable for all sufferers. 2nd, get admission to to PPE was once no longer assessed. After all, some symptomatic individuals with publicity to unwell animals would possibly no longer had been reported, wherein case some human HPAI A(H5N1) infections would possibly had been neglected.
Implications for Public Well being Follow
Public well being companies must paintings with dairy and poultry farms to cut back employee publicity to HPAI A(H5N1) viruses and discover and reply to human circumstances. Prevention, detection, and reaction methods come with PPE use steering, coaching, and distribution; collaboration with farm managers on employee tracking; operating with LHDs to coordinate employee trying out; specimen assortment and laboratory trying out to tell apart influenza A(H5) from seasonal influenza viruses; and distribution of oseltamivir remedy to HPAI A(H5N1) sufferers and oseltamivir prophylaxis to near contacts.§§§ Collaboration amongst public well being, agriculture, animal well being, occupational well being, environmental well being, well being care suppliers, and different state and federal companies is necessary for a coordinated One Well being¶¶¶ reaction and to permit early detection of adjustments in influenza A(H5) viruses that would facilitate human-to-human transmission. Ongoing tracking for genetic adjustments is essential to evaluate the chance of antiviral resistance or human-to-human transmission of HPAI A(H5N1) viruses.
Expanded subtyping**** of influenza viruses would possibly report further circumstances of HPAI A(H5N1) virus an infection and not using a identified publicity (8). Well being departments must evaluation attainable exposures for all HPAI A(H5N1) circumstances to establish the likelihood for human-to-human transmission. Surveillance for HPAI A(H5N1) viruses may just come with expanded subtyping for A(H5) trying out in individuals who meet epidemiologic and both scientific or public well being standards.
Acknowledgments
Individuals with extremely pathogenic avian influenza A(H5N1) who equipped specimens and epidemiologic data; affected farm homeowners and executives who monitored their workers for signs and collaborated with public well being officers; Elisabeth Burnor, Asha Choudhury, Kim Conway, Kristin Cummings, Guinevere Ellison-Giles, Sara Flooring, Curtis Fritz, William Hudspeth, Chloe LeMarchand, Nancy J. Li, Christina Penton, Angela Rabe, Monica Solar, Julie Vaishampayan, Alice Yang, Alexander Yu, California Division of Public Well being; Cynthia Bogert, Jennifer Guide, Vanessa Cadiz, Savanna Hok, Cindy Hua, Jessica Kulow, Ha Le, Aglael Martinez Romero, Stephanie Millena, Lisa Seliskar, Tulare County Division of Well being and Human Services and products; Kings County Division of Public Well being Communicable Illness Surveillance Staff; Vanessa Cardenas, Florante De Ocampo, Eric Vargas, Anthony Villa, Kern County Public Well being; Josh Sanders, Merced County Public Well being; Fresno County Division of Public Well being Communicable Illness Investigation Staff; Priyanka Anand, Megan Dorris, Sascha Ellington, Brendan Flannery, Jerome Leonard, Alexandra Mellis, Dennis Wang, 2024 Influenza A (H5N1) Reaction, CDC; Louise Moncla, the Nextstrain group; the Kristian Andersen Lab.
Los Angeles County H5 Reaction Staff
Annabelle de St. Maurice, Los Angeles County Division of Public Well being; Eric El-Tobgy, Los Angeles County Division of Public Well being; Nicole Inexperienced, Los Angeles County Division of Public Well being; Allison Joyce, Los Angeles County Division of Public Well being; Cristin Mondy, Los Angeles County Division of Public Well being; Taylor Mundt, Los Angeles County Division of Public Well being; Heidi Ransohoff, Los Angeles County Division of Public Well being; Shayra Sanchez, Los Angeles County Division of Public Well being; Elizabeth Traub, Los Angeles County Division of Public Well being
California Division of Public Well being H5 Laboratory Reaction Staff
Matthew Bacinskas, California Division of Public Well being; John Bell, California Division of Public Well being; Cynthia Bernas, California Division of Public Well being; Brandon Brown, California Division of Public Well being; Jahara Cayabyab, California Division of Public Well being; Alice Chen, California Division of Public Well being; Jesse Elder, California Division of Public Well being; Shiffen Getabecha, California Division of Public Well being; Carol Glaser, California Division of Public Well being; Olena Gomez, California Division of Public Well being; Bianca Gonzaga, California Division of Public Well being; Ydelita Gonzales, California Division of Public Well being; Hugo Guevara, California Division of Public Well being; April Hatada, California Division of Public Well being; Katya Ledin, California Division of Public Well being; Deidra Lemoine, California Division of Public Well being; Adrienne Macias, California Division of Public Well being; Sergio Martinez-Paredes, California Division of Public Well being; Blanca Molinar, California Division of Public Well being; Tasha Padilla, California Division of Public Well being; Chao-Yang Pan, California Division of Public Well being; Kiana Pattni, California Division of Public Well being; Rolando Ramirez, California Division of Public Well being; Kao Saechao, California Division of Public Well being; Estela Saguar, California Division of Public Well being; Maria Salas, California Division of Public Well being; Ioana Seritan, California Division of Public Well being; Anthony Tran, California Division of Public Well being; Cindy Wong, California Division of Public Well being; Chelsea Wright, California Division of Public Well being
1Epidemic Intelligence Carrier, CDC; 2California Division of Public Well being; 3Tulare County Division of Well being and Human Services and products, Visalia, California; 4Alameda County Public Well being Division, San Leandro, California; 5Kern County Public Well being, Bakersfield, California; 6Madera County Division of Public Well being, Madera, California; 7Merced County Public Well being, Merced, California; 8Fresno County Division of Public Well being, Fresno, California; 9San Joaquin County Public Well being Services and products, Stockton, California; 10Stanislaus County Well being Services and products Company, Modesto, California; 11Influenza Department, Nationwide Middle for Immunization and Respiration Sicknesses, CDC.
References
Council of State and Territorial Epidemiologists. Replace to public well being reporting and nationwide notification for novel influenza A pandemic an infection. Atlanta, GA: Council of State and Territorial Epidemiologists; 2024.
Uyeki TM, Milton S, Abdul Hamid C, et al. Extremely pathogenic avian influenza A(H5N1) virus an infection in a dairy farm employee. N Engl J Med 2024;390:2028–9. PMID:38700506
Garg S, Reed C, Davis CT, et al. Outbreak of extremely pathogenic avian influenza A(H5N1) viruses in U.S. dairy farm animals and detection of 2 human circumstances—United States, 2024. MMWR Morb Mortal Wkly Rep 2024;73:501–5. PMID:38814843
Burrough ER, Magstadt DR, Petersen B, et al. Extremely pathogenic avian influenza A (H5N1) clade 2.3.4.4b virus an infection in home dairy farm animals and cats, United States, 2024. Emerg Infect Dis 2024;30:1335–43. PMID:38683888
Marshall KE, Drehoff CC, Alden N, et al.; Colorado Box Staff. Non-public protecting apparatus use by means of dairy farmworkers uncovered to cows inflamed with extremely pathogenic avian influenza A(H5N1) viruses—Colorado, 2024. MMWR Morb Mortal Wkly Rep 2024;73:999–1003. PMID:39509648
Verma A, Sharma D, Pant M, et al. First sighting of human H5N1 in Australia: an in depth account and public well being implications. New Microbes New Infect 2024;60-61:101447. PMID:39045288
Jassem AN, Roberts A, Tyson J, et al. Crucial sickness in a teen with influenza A(H5N1) virus an infection. N Engl J Med 2025;392:927–9. PMID:39740022
Garg S, Reinhart Okay, Couture A, et al. Extremely pathogenic avian influenza A (H5N1) virus infections in people. N Engl J Med 2025;392:843–54. PMID:39740051
TABLE 1. Traits of dairy farms with related human extremely pathogenic avian influenza A(H5N1) circumstances — California, September–December 2024
Farm
No. of employees monitored
No. of human circumstances
Days below quarantine* as of December 24, 2024
No. of days from first A(H5) virus detection in cows to first human case
A
Unknown
3
81
6
B
Unknown
2
71
11
C
Unknown
2
60
2
D
40
3
50
10
E
Unknown
1
85
6
F
30
1
95
14
G
Unknown
1
95
13
H
Unknown
1
82
6
I
Unknown
1
85
13
J
10
1
81
6
Okay
7
1
81
6
L
26
1
81
10
M
Unknown
1
70
7
N
Unknown
1
71
5
O
23
1
70
7
P
80
1
81
20
Q
Unknown
1
60
3
R
14
1
57
6
S
Unknown
1
53
10
T
13
1
53
10
U
Unknown
1
41
−7†
V
Unknown
1
39
0
W
Unknown
1
42
12
X
Unknown
1
39
11
Y
11
1
39
12
Z
33
1
39
12
AA
7
3
14
0
BB
Unknown
1
14
5
CC
Unknown
1
11
4
* Farms have been quarantined till reporting no cows with indicators of an infection and 3 consecutive weekly unfavourable exams of bulk milk; no farms with human circumstances have been launched from quarantine via December 24, 2024. Quarantine of unwell cows is essential to cut back farm-to-farm and cow-to-human transmission of extremely pathogenic avian influenza A(H5N1) viruses.
† Employee tracking was once initiated on farm U as a result of A(H5) virus have been detected in cows on different dairy farms with the similar proprietor. The virus was once detected at the farm after the primary human case took place in a farm employee.
TABLE 2. Traits and laboratory result of individuals with showed and possible extremely pathogenic avian influenza A(H5N1) virus an infection — California, September–December 2024
Feature
Showed and possible no. (%)
General
38*
Showed
37 (97.4)
Possible†
1 (2.6)
Median age, yrs (IQR)
43 (32–49)
Race and ethnicity (n = 37)§
White and Hispanic or Latino
24 (64.9)
Unknown race and Hispanic or Latino
13 (35.1)
Number one language
Spanish
27 (71.0)
English
3 (7.9)
Unknown
8 (21.1)
Public well being laboratory take a look at end result
Presumptive sure
37 (97.4)
Detrimental
1 (2.6)
CDC confirmatory end result by means of trying out website¶
Conjunctival swab (n = 37)
35 (94.6)
Nasal/Oropharyngeal swab (n = 29)
8 (27.6)
Nasopharyngeal swab (n = 37)
5 (13.5)
Nasal (n = 6)
2 (33.3)
Oropharyngeal (n = 4)
1 (25.0)
Scientific indicators and signs
Eye inflammation or redness
37 (97.4)
Fever**
11 (28.9)
Muscle aches
13 (34.2)
Headache
10 (26.3)
Sore throat
6 (15.8)
Cough
6 (15.8)
Shortness of breath
4 (10.5)
Vomiting
2 (5.3)
Diarrhea
2 (5.3)
Fatigue
7 (18.4)
Dairy farm publicity
37 (97.4)
Function on dairy farm (n = 37)
Milker
23 (62.2)
Farmhand
2 (5.4)
Different††
3 (8.1)
Unknown
9 (24.3)
Distinctive dairy farms the place circumstances took place
29
Reported use of any non-public protecting apparatus§§ at paintings (n = 32)
Sure
29 (78.4)
No
5 (13.5)
Unknown
3 (9.4)
Affected person presented oseltamivir
Authorised
36 (94.7)
Declined
2 (5.3)
Hospitalized
Sure
0 (—)
No
38 (100)
* Desk contains 37 individuals with occupational publicity to inflamed dairy cows and one with an unknown publicity supply to influenza A(H5).
† https://cdn.ymaws.com/www.cste.org/useful resource/resmgr/position_statements_files_2023/24-ID-09_Novel_Influenza_A.pdf
§ Race and ethnicity no longer described for one consumer to offer protection to privateness.
¶ Some circumstances have been showed with a couple of specimen.
** Measured or subjective fever.
†† Farmhands and individuals within the “Different” classes have been in roles with shut touch with unwell cows.
§§ Eye coverage (together with goggles), gloves, robe, or boots.
FIGURE. Phylogenetic tree* of 16 entire genome extremely pathogenic avian influenza A(H5N1) viruses, by means of identity and assortment date, from human circumstances — California, September–December 2024
* Tree was once created with Ultrafast Pattern placement on Current tRee (UShER). and Auspice
Prompt quotation for this newsletter: Zhu S, Harriman Okay, Liu C, et al. Human Instances of Extremely Pathogenic Avian Influenza A(H5N1) — California, September–December 2024. MMWR Morb Mortal Wkly Rep 2025;74:127–133. DOI:
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