Geospatial evidence of introduction of highly pathogenic avian influenza into dairy farms in the United States
Year: 2024
Type: preprint
Abstract: The emergence of Highly Pathogenic Avian Influenza (HPAI) A/H5N1 clade 2.3.4.4b has led to unprecedented intercontinental spread spread across avian and mammalian species. First confirmed outbreaks in dairy farms happened in the United States in March 2024. This study evaluated the modes of introduction and spread across 42 confirmed dairy farm outbreaks spanning nine states between 10 March and 5 May 2024, through geospatial mapping, case-control ecological exposure analysis, and space-time cluster testing. Non-waterfowl abundance was significantly higher in outbreak counties than in high-cattle-density non-outbreak counties (p<0.00001, r=−0.542), identifying it as a distinguishing ecological feature of early dairy outbreak locations. Knox space-time cluster analysis confirmed non-random transmission dynamics across 14 of 30 threshold combinations, consistent with a single introduction in Texas followed by regional and trade-mediated amplification, with livestock trade, poultry litter, and contaminated milking equipment as likely contributing factors. Proactive surveillance targeting counties with high non-waterfowl abundance and cattle density is essential to reduce the risk of further spillover events.
Source: medRxiv
Institutions: UNSW Sydney, Kirby Institute, Arizona State University
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W4396646647