Limiting spread of low pathogenicity avian influenza (LPAI) during an outbreak is critical to reduce the negative impact on poultry producers and local economies. Mathematical models of disease transmission can support outbreak control efforts by estimating relevant epidemiological parameters. In this article, diagnostic testing data from each house on a premises infected during a LPAI H5N2 outbreak in the state of Minnesota in the United States in 2018 was used to estimate the time of virus introduction and adequate contact rate, which determines the rate of disease spread. A well-defined most likely time of virus introduction, and upper and lower 95% credibility intervals were estimated for each house. The length of the 95% credibility intervals ranged from 11 to 22 with a mean of 17 days. In some houses the contact rate estimates were also well-defined; however, the estimated upper 95% credibility interval bound for the contact rate was occasionally dependent on the upper bound of the prior distribution. The estimated modes ranged from 0.5 to 6.0 with a mean of 2.8 contacts per day. These estimates can be improved with early detection, increased testing of monitored premises, and combining the results of multiple barns that possess similar production systems.
Bibliographical noteFunding Information:
The authors thank Michelle Kromm, Jill Nezworski, Megan Lighty, Dale Lauer, Shauna Voss, Mary Donahue, and Stacy Pollock for assistance in obtaining the diagnostic testing data. The authors acknowledge the Minnesota Supercomputing Institute (MSI) and the University of Minnesota for providing resources that contributed to the research results reported within this paper. PB, SM, AS, MC, and CC acknowledge funding of their work by sponsored project contract number CON000000075615 (Secure Food Systems Team Contract with the State of Minnesota Board of Animal Health) and from a cooperative agreement between the Center for Epidemiology and Animal Health (CEAH) of the United States Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS) Veterinary Services (VS) and the University of Minnesota (UMN) as USDA Award # AP18VSCEAH00C016 (Risk Analysis and Modeling to Manage HPAI and Other Animal Disease Emergencies). CC is also funded by the B.S. Pomeroy Chair in Avian Health at the University of Minnesota College of Veterinary Medicine.
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