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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #386139

Research Project: Intervention Strategies to Control Influenza A Virus Infection in Swine

Location: Virus and Prion Research

Title: Transmission bottlenecks during adaptation of human influenza A virus to pigs

item RAJAO, DANIELA - University Of Georgia
item PEREZ, DANIEL - University Of Georgia
item Baker, Amy
item Anderson, Tavis

Submitted to: Conference Research Workers Disease Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/20/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Influenza is one of the most prevalent respiratory diseases of swine, leading to significant losses in pork production. The frequent spillover of human seasonal influenza viruses to swine has greatly contributed to the genetic and antigenic diversity of influenza A viruses (IAV) circulating in pigs. However, only few human viruses transmitted to pigs become established in the new host, usually carrying changes acquired by mutation or reassortment. Despite the impact of human-to-swine transmissions in the epidemiology of IAV in swine, little is known about virus evolution and adaptation when IAVs are transmitted from humans to pigs. The purpose of this study was to investigate the molecular factors and bottlenecks during the adaptation of IAV between humans and pigs. To evaluate the within and between host evolution of human IAV in pigs, we will perform serial transmissions of a reassortant virus containing human seasonal HA and NA genes with a swine-origin backbone (herein referred to as VICHA/NA:6TRIGpdm) in pigs. Low passage virus stocks were prepared, titrated, and sequenced for the reassortant human IAV and a swine-adapted control virus containing the same backbone (7OH04:1pdm). The infectious dose 50 (ID50) for each virus will be determined in a pilot study. Pigs will then be inoculated intranasally with each virus in sets of 3, each pig kept in a separate enclosure. Two days later, contact pigs will be introduced in each enclosure. The inoculated pigs will be euthanized, and new contacts introduced, following with 5 more consecutive transmissions. Nasal swabs will be collected and sequenced using high-throughput Illumina MiSeq platform. Variant analysis will be performed and viral diversity within and between hosts quantified. We expect to identify the molecular signatures that allow human influenza viruses to become adapted to swine.