A One Health Investigation into H5N1 Avian Influenza Virus Epizootics on Two Dairy Farms.
Ismaila Shittu1
Diego Silva1
Judith U Oguzie1
Lyudmyla V Marushchak1
Gene G Olinger2
John A Lednicky3,4
Claudia M Trujillo-Vargas1
Nicholas E Schneider5
Haiping Hao6
Gregory C Gray1,7,8,9
Affiliations9 institutions
Division of Infectious Diseases, Department of Medicine, University of Texas Medical Branch, Galveston, Texas, USA.
Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, USA.
Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA.
Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA.
Schneider Veterinary Services, Milliken, Colorado, USA.
Nextgen Sequencing Core, University of Texas Medical Branch, Galveston, Texas, USA.
Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA.
Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA.
Department of Global Health, School of Public and Population Health, University of Texas Medical Branch, Galveston, Texas, USA.
In early April 2024 we studied 2 Texas dairy farms that had suffered incursions of H5N1 highly pathogenic avian influenza virus (HPAIV) the previous month. We employed molecular assays, cell and egg culture, Sanger and next generation sequencing to isolate and characterize viruses from multiple farm specimens (cow nasal swab, milk specimens, fecal slurry, and a dead bird). We detected H5N1 HPAIV in 64% (9/14) of milk specimens, 2.6% (1/39) of cattle nasal swab specimens, and none of 17 cattle worker nasopharyngeal swab specimens. We cultured and characterized virus from 8 H5N1-positive specimens. Sanger and next-generation sequencing revealed the viruses were closely related into other recent Texas epizootic H5N1 strains of clade 2.3.4.4b. Our isolates had multiple mutations associated with increased spillover potential. Surprisingly, we detected severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a nasal swab from a sick cow. Additionally, 14.3% (2/14) of the farm workers who donated sera were recently symptomatic and had elevated neutralizing antibodies against a related H5N1 strain. Although our sampling was limited, these data offer additional insight into the large H5N1 HPAIV epizootic, which has rapidly spread in the United States. Due to fears that research might damage dairy businesses, studies like this one have been few. We need to find ways to work with dairy farms in collecting more comprehensive epidemiological data that are necessary for the design of future interventions against H5N1 HPAIV on cattle farms.
avian influenzadairy cattle farmdairy workersepidemiologyinfluenzaCattle DiseasesInfluenza A Virus, H5N1 SubtypeInfluenza in BirdsInfluenza, HumanOne HealthAnimalsBirdsCattleDairyingFarmsFecesFemaleHumans
Structured evidence records
Evidence records
10 total
Zoonotic Surveillance3 records
Zoonotic SurveillanceExtraction confidence 0.95
Key finding
H5N1 highly pathogenic avian influenza virus was detected through molecular surveillance of cattle and farm specimens on two Texas dairy farms.
We employed molecular assays, cell and egg culture, Sanger and next generation sequencing to isolate and characterize viruses from multiple farm specimens (cow nasal swab, milk specimens, fecal slurry, and a dead bird). We detected H5N1 HPAIV in 64% (9/14) of milk specimens, 2.6% (1/39) of cattle nasal swab specimens, and none of 17 cattle worker nasopharyngeal swab specimens.
Additionally, 14.3% (2/14) of the farm workers who donated sera were recently symptomatic and had elevated neutralizing antibodies against a related H5N1 strain.
Method
serology
Sample type
serum
Geographic raw
Texas
Country inferred
United States
Zoonotic SurveillanceExtraction confidence 0.85
Key finding
SARS-CoV-2 was detected by molecular testing in a nasal swab from a dairy cow, indicating surveillance of another zoonotic virus during the outbreak investigation.
We employed molecular assays, cell and egg culture, Sanger and next generation sequencing to isolate and characterize viruses from multiple farm specimens (cow nasal swab, milk specimens, fecal slurry, and a dead bird).
14.3% (2/14) of the farm workers who donated sera were recently symptomatic and had elevated neutralizing antibodies against a related H5N1 strain.
Method
serology; neutralization assay
Study design
serological survey
Transmission direction
animal-to-human
Geographic raw
Texas
Country inferred
United States
Cross Species Transmission1 records
Cross Species TransmissionExtraction confidence 0.90
Key finding
H5N1 highly pathogenic avian influenza virus was detected in cattle and bird specimens from Texas dairy farms, supporting cross-species transmission between birds and cattle.
We employed molecular assays, cell and egg culture, Sanger and next generation sequencing to isolate and characterize viruses from multiple farm specimens (cow nasal swab, milk specimens, fecal slurry, and a dead bird). We detected H5N1 HPAIV in 64% (9/14) of milk specimens, 2.6% (1/39) of cattle nasal swab specimens, and none of 17 cattle worker nasopharyngeal swab specimens.
Sanger and next-generation sequencing revealed the viruses were closely related to other recent Texas epizootic H5N1 strains of clade 2.3.4.4b. Our isolates had multiple mutations associated with increased spillover potential.
Sanger and next-generation sequencing revealed the viruses were closely related to other recent Texas epizootic H5N1 strains of clade 2.3.4.4b. Our isolates had multiple mutations associated with increased spillover potential.
Mechanism types
spillover_potential; molecular_adaptation
Outbreak Investigation1 records
Outbreak InvestigationExtraction confidence 0.90
Key finding
H5N1 HPAIV caused an outbreak on two Texas dairy farms affecting cattle, with limited evidence of exposure among farm workers.
In early April 2024 we studied 2 Texas dairy farms that had suffered incursions of H5N1 highly pathogenic avian influenza virus (HPAIV) the previous month. We detected H5N1 HPAIV in 64% (9/14) of milk specimens, 2.6% (1/39) of cattle nasal swab specimens, and none of 17 cattle worker nasopharyngeal swab specimens.
Method
molecular assays; cell and egg culture; Sanger sequencing; next generation sequencing
Transmission direction
unknown
Geographic raw
Texas
Country inferred
United States
Outbreak setting
Texas dairy farms
Outbreak time
early April 2024
Outbreak scale
64% (9/14) of milk specimens, 2.6% (1/39) of cattle nasal swab specimens
Serological Evidence1 records
Serological EvidenceExtraction confidence 0.85
Key finding
Two of fourteen dairy farm workers had elevated neutralizing antibodies against H5N1 virus, indicating recent exposure.
Additionally, 14.3% (2/14) of the farm workers who donated sera were recently symptomatic and had elevated neutralizing antibodies against a related H5N1 strain.
