Title: Absence of clinical disease and contact transmission of HPAI H5NX clade 2.3.4.4 from North America in experimentally infected pigs

Abstract

Background In the fall of 2014, highly pathogenic avian influenza (HPAI) subtype H5N8 clade 2.3.4.4 was introduced into North America by migrating waterfowl from Asia where, through reassortment, novel HPAI H5N2 and H5N1 viruses emerged. Objectives Assess the susceptibility of pigs to HPAI H5N1, H5N2, and H5N8 clade 2.3.3.3 from North America. Methods Pigs and trachea explants were inoculated with a representative panel of H5NX clade 2.3.4.4 HPAI viruses from North America. Nasal swabs, BALF, and sera were collected to assess replication and transmission in challenged and direct contact pigs by RRT‐PCR, virus isolation, hemagglutination inhibition, and ELISA. Results Limited virus replication was restricted to the lower respiratory tract of challenged pigs, though absent in the nasal passages and trachea cultures, as determined by RRT‐PCR in all samples. Seroconversion of inoculated pigs was detected by NP ELISA but was not reliably detected by antigen‐specific hemagglutination inhibition. Boost with adjuvanted virus was required for the production of neutralizing antibodies to assess cross‐reactivity between wild‐type avian strains. All RRT‐PCR and serology tests were negative for contact animals indicating a failure of transmission from primary inoculated pigs. Conclusions H5NX clade 2.3.4.4 strains can replicate in the lower respiratory tract of swine upon highmore » titer inoculation, though appear to be incapable of replication in swine nasal epithelium in vivo or ex vivo in trachea explants in culture. Infected pigs did not produce high levels of serum antibodies following infection. Collectively, our data show HPAI H5NX clade 2.3.4.4 viruses to be poorly adapted for replication and transmission in swine.« less

Authors:

Kaplan, Bryan S.  ^[1];

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Torchetti, Mia K. ^[2]; Lager, Kelly M. ^[1]; Webby, Richard J. ^[3]; Vincent, Amy L. ^[1]

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+ Show Author Affiliations

1. USDA Agricultural Research Service Virus and Prion Research Unit National Animal Disease Center Ames IA USA
2. USDA Animal and Plant Health Inspection Service National Veterinary Services Laboratory Ames IA USA
3. Department of Infectious Diseases St. Jude Children's Research Hospital Memphis TN USA

Publication Date:

Sat Sep 02 00:00:00 EDT 2017

Research Org.:

Oak Ridge Associated Univ., Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC); Oak Ridge Institute for Science and Education; Agricultural Research Service; National Institute of Allergy and Infectious Diseases (NIAID); Animal and Plant Health Inspection Service

OSTI Identifier:

1378274

Alternate Identifier(s):

OSTI ID: 1378275; OSTI ID: 1625883

Grant/Contract Number:  

AC05-06OR23100; HHSN272201400006C

Resource Type:

Published Article

Journal Name:

Influenza and Other Respiratory Viruses

Additional Journal Information:

Journal Name: Influenza and Other Respiratory Viruses Journal Volume: 11 Journal Issue: 5; Journal ID: ISSN 1750-2640

Publisher:

Wiley-Blackwell

Country of Publication:

Country unknown/Code not available

Language:

English

Subject:

Infectious Diseases; Virology; clade 2.3.4.4; H5; highly pathogenic avian influenza; influenza; North America; pigs; swine