Abstract Title
Comparative Pathology of highly pathogenic avian influenza in naturally infected New England wildlife
Abstract
In 2021, H5N1 highly pathogenic avian influenza (HPAI) virus was introduced to the Atlantic migratory flyway and spread around the globe. Historically, avian influenza (AI) viruses have circulated in North American wild birds, typically infecting the gastrointestinal (GI) tract with limited morbidity and mortality in reservoir species. This H5N1 virus is unprecedented in both disease severity and the diversity of species affected, including frequent mammalian spillover. H5N1 HPAI shows increased neurotropism compared to other AI viruses with most clinical cases presenting with neurologic signs.
Wild birds admitted to rehabilitation clinics or found deceased were opportunistically sampled to characterize the pathology of HPAI in naturally infected hosts. 35 birds representing 6 orders were confirmed H5 positive via RT-PCR and necropsied. All birds examined alive had neurologic signs such as ataxia and tremors. Macroscopic changes were observed in the brain, pancreas, spleen, and GI tract in most birds. Additional testing is underway using immunohistochemistry and in situ hybridization (RNAscope) to determine the relationship of lesions to active viral infection. We hypothesize that neurologic signs observed in animals with H5N1 are, in part, caused by enhanced viral replication within the brain and that this is consistent across avian species. The novel documentation of severe, multi-organ pathologic changes associated with H5N1 across a wide taxonomic group, supports the need for comprehensive. Further pathologic investigation of wild avian and mammalian hosts of H5 HPAI, along with sequencing, will increase understanding of H5N1 behavior and help identify risk factors to protect human and animal health.
Wild birds admitted to rehabilitation clinics or found deceased were opportunistically sampled to characterize the pathology of HPAI in naturally infected hosts. 35 birds representing 6 orders were confirmed H5 positive via RT-PCR and necropsied. All birds examined alive had neurologic signs such as ataxia and tremors. Macroscopic changes were observed in the brain, pancreas, spleen, and GI tract in most birds. Additional testing is underway using immunohistochemistry and in situ hybridization (RNAscope) to determine the relationship of lesions to active viral infection. We hypothesize that neurologic signs observed in animals with H5N1 are, in part, caused by enhanced viral replication within the brain and that this is consistent across avian species. The novel documentation of severe, multi-organ pathologic changes associated with H5N1 across a wide taxonomic group, supports the need for comprehensive. Further pathologic investigation of wild avian and mammalian hosts of H5 HPAI, along with sequencing, will increase understanding of H5N1 behavior and help identify risk factors to protect human and animal health.
Co-Author(s)
Jonathon J. Stone, Elena C. Cox, Claire Lyons, Autumn Berlied, Alexa Simulynas, Wendy Puryear, Maureen Murray, Amanda J. Martinot, Jonathan A. Runstadler
Cummings School of Veterinary Medicine at Tufts University
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds