Abstract
Background: The genetic and antigenic characteristics of influenza A viruses (IAV) within and between species change over time due to antigenic shift and drift. Although pigs are known to play a key role in the epidemiology of IAV between species, little is known about the molecular evolution of IAV hemagglutinin (HA) in pigs. Objectives: The aim of this study was to evaluate the HA drift of an H1N1 IAV after infecting weaned pigs with or without maternally derived passive immunity. Methods: Three- to four-week-old piglets born either to vaccinated or unvaccinated sows were contact-infected upon exposure with an IAV-infected pig. Nasal swabs were collected daily from each pig and tested for IAV by RRT-PCR. Full-length HA sequences were obtained directly from positive nasal swabs and compared between groups. Results: Synonymous and non-synonymous mutations were detected in pigs with and without passive immunity. Most of the non-synonymous mutations occurred within the HA1 region of the HA. Changes within HA1 region were only identified in antigenic site B in pigs without passive immunity and in antigenic sites A, B, and D in pigs with passive immunity. However, there was no association between the immune status of the pig and the amino acid substitutions observed. Conclusions: Overall, we demonstrated that amino acid substitutions within antigenic sites can happen in weaned pigs with or without passive immunity shortly after infection.
Original language | English (US) |
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Pages (from-to) | 52-60 |
Number of pages | 9 |
Journal | Influenza and other Respiratory Viruses |
Volume | 7 |
Issue number | SUPPL.4 |
DOIs | |
State | Published - Dec 2013 |
Keywords
- Antigenic drift
- Passive immunity
- Swine influenza