Dynamics of virus shedding and antibody responses in influenza A virus-infected feral swine

Authors

Hailiang Sun, Mississippi State University
Fred L. Cunningham, USDA National Wildlife Research CenterFollow
Jillian Harris, Mississippi State University
Yifei Xu, Mississippi State University
Li-Ping Long, Mississippi State University
Katie C. Hanson-Dorr, USDA National Wildlife Research CenterFollow
John A. Baroch, USDA National Wildlife Research Center
Paul Fioranelli, USDA National Wildlife Research Center
Mark W. Lutman, USDA APHIS Wildlife Services
Tao Li, Walter Reed Army Institute of Research
Kerri Pedersen, USDA APHIS Wildlife ServicesFollow
Brandon S. Schmit, USDA APHIS Wildlife ServicesFollow
Jim Cooley, Mississippi State University
Xiaoxu Lin, Walter Reed Army Institute of Research
Richard G. Jarman, Walter Reed Army Institute of Research
Thomas J. DeLiberto, USDA APHIS Wildlife ServicesFollow
Xui-Feng Wan, Mississippi State UniversityFollow

Document Type

Article

Date of this Version

2015

Citation

Journal of General Virology (2015), 96, pp. 2569–2578, DOI 10.1099/jgv.0.000225 000225.

Comments

U.S. government work.

Abstract

Given their free-ranging habits, feral swine could serve as reservoirs or spatially dynamic ‘mixing vessels’ for influenza A virus (IAV). To better understand virus shedding patterns and antibody response dynamics in the context of IAV surveillance amongst feral swine, we used IAV of feral swine origin to perform infection experiments. The virus was highly infectious and transmissible in feral swine, and virus shedding patterns and antibody response dynamics were similar to those in domestic swine. In the virus-inoculated and sentinel groups, virus shedding lasted ≤6 and ≤9 days, respectively. Antibody titres in inoculated swine peaked at 1 : 840 on day 11 post-inoculation (p.i.), remained there until 21 days p.i. and dropped to: 220 at 42 days p.i. Genomic sequencing identified changes in wildtype (WT) viruses and isolates from sentinel swine, most notably an amino acid divergence in nucleoprotein position 473. Using data from cell culture as a benchmark, sensitivity and specificity of a matrix gene-based quantitative reverse transcription-PCR method using nasal swab samples for detection of IAV in feral swine were 78.9 and 78.1 %, respectively. Using data from haemagglutination inhibition assays as a benchmark, sensitivity and specificity of an ELISA for detection of IAV-specific antibody were 95.4 and 95.0 %, respectively. Serological surveillance from 2009 to 2014 showed that ~7.58 % of feral swine in the USA were positive for IAV. Our findings confirm the susceptibility of IAV infection and the high transmission ability of IAV amongst feral swine, and also suggest the need for continued surveillance of IAVs in feral swine populations.