tetano
Editor, Senior Moderator
Prev Vet Med
. 2026 Sep 24:257:107022.
doi: 10.1016/j.prevetmed.2026.107022. Online ahead of print.
N Uribe Corrales 1 , R Anderson 1 , M Elramady 2 , Betsy M Karle 3 , S Aly 4
Affiliations
The 2024 emergence of Highly Pathogenic Avian Influenza (HPAI) H5N1, clade 2.3.4.4b, genotype B3.13, in U.S. dairy cattle was a novel disease event affecting animal health, production, and public health. We conducted structured interviews with managers of eight H5N1-positive dairies in Tulare County, California, the epicenter of the 2024 outbreak, covering a 30-day reference period, the first quarantine, the 30 days following quarantine release, and, for two dairies, a second quarantine. Given the small sample, we used descriptive statistics with Multiple Factor Analysis and hierarchical clustering to explore herd heterogeneity. Mean milk yield declined modestly (2.6%) during early quarantine but recovered above baseline by release; somatic cell count rose 21% and remained elevated. Three-quarters of dairies reported abnormal milk appearance, all experienced reduced feed intake (~8%) and pregnancy losses, and mortality in lactating cows averaged 1.5%. Biosecurity improvements were largely reactive rather than preventive. Exploratory multivariate analyses identified two underlying dimensions and three distinct herd profiles differing in production, clinical course, and biosecurity intensity. In this work, H5N1 infection was associated with variable but measurable impacts on production, mammary health, and reproduction; findings are consistent with reports from other states but warrant confirmation in larger, more diverse studies.
Keywords: Avian influenza H5N1; Biosecurity; Dairy cattle; Field survey; One Health; Outbreak.
. 2026 Sep 24:257:107022.
doi: 10.1016/j.prevetmed.2026.107022. Online ahead of print.
H5N1 epidemiology and production impact in eight California dairy herds at the outbreak epicenter
N Uribe Corrales 1 , R Anderson 1 , M Elramady 2 , Betsy M Karle 3 , S Aly 4
Affiliations
- PMID: 42826600
- DOI: 10.1016/j.prevetmed.2026.107022
Abstract
The 2024 emergence of Highly Pathogenic Avian Influenza (HPAI) H5N1, clade 2.3.4.4b, genotype B3.13, in U.S. dairy cattle was a novel disease event affecting animal health, production, and public health. We conducted structured interviews with managers of eight H5N1-positive dairies in Tulare County, California, the epicenter of the 2024 outbreak, covering a 30-day reference period, the first quarantine, the 30 days following quarantine release, and, for two dairies, a second quarantine. Given the small sample, we used descriptive statistics with Multiple Factor Analysis and hierarchical clustering to explore herd heterogeneity. Mean milk yield declined modestly (2.6%) during early quarantine but recovered above baseline by release; somatic cell count rose 21% and remained elevated. Three-quarters of dairies reported abnormal milk appearance, all experienced reduced feed intake (~8%) and pregnancy losses, and mortality in lactating cows averaged 1.5%. Biosecurity improvements were largely reactive rather than preventive. Exploratory multivariate analyses identified two underlying dimensions and three distinct herd profiles differing in production, clinical course, and biosecurity intensity. In this work, H5N1 infection was associated with variable but measurable impacts on production, mammary health, and reproduction; findings are consistent with reports from other states but warrant confirmation in larger, more diverse studies.
Keywords: Avian influenza H5N1; Biosecurity; Dairy cattle; Field survey; One Health; Outbreak.