{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,26]],"date-time":"2026-01-26T19:07:35Z","timestamp":1769454455304,"version":"3.49.0"},"reference-count":33,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,26]],"date-time":"2026-01-26T00:00:00Z","timestamp":1769385600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the National Bio and Agro-Defense Facility (NBAF) Transition Fund from the State of Kansas","award":["P20GM130448"],"award-info":[{"award-number":["P20GM130448"]}]},{"name":"the NIAID supported Centers of Excellence for Influenza Research and Response","award":["75N93021C00016"],"award-info":[{"award-number":["75N93021C00016"]}]},{"name":"the Louisiana State University, School of Veterinary Medicine start-up","award":["PG 002165"],"award-info":[{"award-number":["PG 002165"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Since its emergence in 2019, SARS-CoV-2 has resulted in more than 7.1 million deaths worldwide. It has been shown that co-infection with influenza A virus (IAV) can worsen clinical symptoms in COVID-19 patients and small animal models have been used to elucidate the molecular mechanisms of co-infection between SARS-CoV-2 and IAV. This study aimed to establish a co-infection model in pigs, a natural reservoir for IAV but resistant to SARS-CoV-2 infection, by determining whether pigs become susceptible to SARS-CoV-2 following a primary IAV infection. Here, pigs were primarily infected with swine influenza A virus (SIV) via the intratracheal route and, 3 days later, secondarily challenged with SARS-CoV-2. SIV was isolated from nasal swabs, and pigs seroconverted to SIV. In contrast, SARS-CoV-2 RNA was detected in nasal and oropharyngeal swabs only at day 1 post-secondary challenge, with no evidence of seroconversion against SARS-CoV-2. These data indicate that pigs are not susceptible to SARS-CoV-2 following SIV infection and therefore are not a suitable model for IAV\/SARS-CoV-2 co-infection research.<\/jats:p>","DOI":"10.3390\/pathogens15020134","type":"journal-article","created":{"date-parts":[[2026,1,26]],"date-time":"2026-01-26T08:14:23Z","timestamp":1769415263000},"page":"134","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Influenza-Infected Pigs Are Not Susceptible to SARS-CoV-2 Infection"],"prefix":"10.3390","volume":"15","author":[{"given":"Taeyong","family":"Kwon","sequence":"first","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3864-5915","authenticated-orcid":false,"given":"Mariano","family":"Carossino","sequence":"additional","affiliation":[{"name":"Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA"},{"name":"Louisiana Animal Disease Diagnostic Laboratory, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9343-5446","authenticated-orcid":false,"given":"Igor","family":"Morozov","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dashzeveg","family":"Bold","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7195-785X","authenticated-orcid":false,"given":"Natasha N.","family":"Gaudreault","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5644-022X","authenticated-orcid":false,"given":"Jessie D.","family":"Trujillo","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3666-0214","authenticated-orcid":false,"given":"Konner","family":"Cool","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8452-7288","authenticated-orcid":false,"given":"Chester D.","family":"McDowell","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bianca","family":"Libanori Artiaga","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-2553-6043","authenticated-orcid":false,"given":"Daniel W.","family":"Madden","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1671-5572","authenticated-orcid":false,"given":"Velmurugan","family":"Balaraman","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7877-9224","authenticated-orcid":false,"given":"William C.","family":"Wilson","sequence":"additional","affiliation":[{"name":"Foreign Arthropod-Borne Animal Disease Research Unit, National Bio and Agro-Defense Facility, United States Department of Agriculture, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0609-678X","authenticated-orcid":false,"given":"Udeni B. R.","family":"Balasuriya","sequence":"additional","affiliation":[{"name":"Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7308-5672","authenticated-orcid":false,"given":"Juergen A.","family":"Richt","sequence":"additional","affiliation":[{"name":"Department of Diagnostic Medicine\/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,26]]},"reference":[{"key":"ref_1","unstructured":"Centers for Diseases Control and Prevention (2026, January 09). 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