A One Health Investigation into H5N1 Avian Influenza Virus Epizootics on Two Dairy Farms

Ismaila Shittu; Diego Silva; Judith U Oguzie; Lyudmyla V Marushchak; Gene G Olinger; John A Lednicky; Claudia M Trujillo-Vargas; Nicholas E Schneider; Haiping Hao; Gregory C Gray

doi:10.1093/cid/ciae576

A One Health Investigation into H5N1 Avian Influenza Virus Epizootics on Two Dairy Farms

Clin Infect Dis. 2024 Dec 10:ciae576. doi: 10.1093/cid/ciae576. Online ahead of print.

Authors

Affiliations

¹ Division of Infectious Diseases, Department of Medicine, University of Texas Medical Branch; Galveston, TX, 77555, USA.
² Galveston National Laboratory, University of Texas Medical Branch; Galveston, TX, 77555, USA.
³ Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida; Gainesville, FL 32610, USA.
⁴ Emerging Pathogens Institute, University of Florida; Gainesville, FL 32610, USA.
⁵ Schneider Veterinary Services. Milliken, CO, USA.
⁶ Nextgen Sequencing Core, University of Texas Medical Branch; Galveston, TX, 77555, USA.
⁷ Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.
⁸ Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA.
⁹ Department of Global Health, School of Public and Population Health, University of Texas Medical Branch, Galveston, TX, USA.

PMID: 39658318
DOI: 10.1093/cid/ciae576

Abstract

Background: In early April 2024 we studied two Texas dairy farms which had suffered incursions of H5N1 highly pathogenic avian influenza virus (HPAIV) the previous month.

Methods: 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).

Results: 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 eight 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 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.

Conclusions: While 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.

Keywords: avian influenza; dairy cattle farm; dairy workers; epidemiology; influenza.

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