Abstract Title
Highly Pathogenic Avian Influenza (HPAI H5N1, Clade 2.3.4.4b, genotype C2.1) in Commercial Ring-Necked Pheasants During the 2022 Outbreak in the United States
Abstract
Highly pathogenic avian influenza (HPAI) virus clade 2.3.4.4b was first introduced into North America by wild birds in late 2021. In early 2022, HPAI spilled into domestic poultry in the United States (U.S.), resulting in the current and largest HPAI outbreak in U.S. history. In the winter of 2023, HPAI H5N1 2.3.4.4b was identified as the cause of elevated mortality in 28-week-old commercial raised-for-release ring-necked pheasants in Pennsylvania. The farm owner reported slightly elevated mortality over a period of four days in one flight pen out of 50 on the premises. Upon observation of the affected pen, approximately 5% of the birds were observed sitting down or exhibiting labored breathing. No obvious neurologic signs were reported. HPAI was identified by quantitative RT-PCR; gene sequencing confirmed genotype C2.1 with phylodynamic analyses providing evidence of a wild bird introduction. In this report, we describe the clinicopathologic features and viral antigen distribution in affected pheasants that were submitted from the farm for postmortem evaluation. Enlarged, mottled spleens and bilateral lung congestion were consistent gross findings. Viral antigen was detected in various organs, including spleen and lung. Predictive mathematical modeling estimates the time of virus introduction onto the farm was similar or longer than previously described for domestic poultry. Biosecurity and biocontainment procedures of the affected farm appeared to prevent subsequent spread to additional pens or contact premises. In addition to characterizing the outbreak, we consider missed opportunities to better understand the field dynamics of this virus in gamebirds and other domestic poultry.
Co-Author(s)
Kayla R Niel, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA 16802 USA
Kaitlyn M St. Charles, Secure Food Systems Team, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108 USA
Jonathan Elissa, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA 16802 USA and Washington Animal Disease Diagnostic Laboratory, Department of Veterinary Microbiology and Pathology, Washington State University, Pyallup, WA 98371
Megan E Lighty, Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, PA 16802 USA
Amos Ssematimba, Secure Food Systems Team, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108 USA and Department of Mathematics, Faculty of Science, Gulu University, P.O. Box 166, Gulu, Uganda
Marie Culhane, Secure Food Systems Team, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108 USA
Alvin Crespo-Bellido, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
Nidia Trovao, Fogarty International Center, National Institutes of Health, Bethesda, MD 20892
Martha Nelson, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
Carol Cardona, Secure Food Systems Team, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108 USA
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in poultry