Longitudinal study of influenza A virus circulation in a nursery swine barn
Abstract Commercial production of swine often involves raising animals in large groups through the use of multi-stage production systems. In such systems, pigs can experience different degrees of contact with animals of the same or different ages. Population size and degree of contact can greatly in...
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| Format: | Article |
| Language: | English |
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BMC
2017-10-01
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| Series: | Veterinary Research |
| Online Access: | http://link.springer.com/article/10.1186/s13567-017-0466-x |
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| author | Juliana B. Ferreira Helena Grgić Robert Friendship Greg Wideman Éva Nagy Zvonimir Poljak |
| author_facet | Juliana B. Ferreira Helena Grgić Robert Friendship Greg Wideman Éva Nagy Zvonimir Poljak |
| author_sort | Juliana B. Ferreira |
| collection | DOAJ |
| description | Abstract Commercial production of swine often involves raising animals in large groups through the use of multi-stage production systems. In such systems, pigs can experience different degrees of contact with animals of the same or different ages. Population size and degree of contact can greatly influence transmission of endemic pathogens, including influenza A virus (IAV). IAV can display high genetic variability, which can further complicate population-level patterns. Yet, the IAV transmission in large multi-site swine production systems has not been well studied. The objectives of this study were to describe the IAV circulation in a multi-source nursery facility and identify factors associated with infection in nursery pigs. Pigs from five sow herds were mixed in one all-in/all-out nursery barn, with 81 and 75 pigs included in two longitudinal studies. Virus isolation was performed in Madin-Darby canine kidney cells and serology was performed using hemagglutination inhibition assays. Risk factor analysis for virological positivity was conducted using logistic regression and stratified Cox’s regression for recurrent events. In Study 1, at ≈30 days post-weaning, 100% of pigs were positive, with 43.2% of pigs being positive recurrently over the entire study period. In study 2, 48% of pigs were positive at the peak of the outbreak, and 10.7% were positive recurrently over the entire study period. The results suggest that IAV can circulate during the nursery phase in an endemic pattern and that the likelihood of recurrent infections was associated in a non-linear way with the level of heterologous (within-subtype) maternal immunity (p < 0.05). High within-pen intracluster correlation coefficients (> 0.75) were also observed for the majority of sampling times suggesting that pen-level factors played a role in infection dynamics in this study. |
| first_indexed | 2024-12-11T09:05:07Z |
| format | Article |
| id | doaj.art-2c4458ffa98e49bf9b37633f442ed57b |
| institution | Directory Open Access Journal |
| issn | 1297-9716 |
| language | English |
| last_indexed | 2024-12-11T09:05:07Z |
| publishDate | 2017-10-01 |
| publisher | BMC |
| record_format | Article |
| series | Veterinary Research |
| spelling | doaj.art-2c4458ffa98e49bf9b37633f442ed57b2022-12-22T01:13:38ZengBMCVeterinary Research1297-97162017-10-0148111610.1186/s13567-017-0466-xLongitudinal study of influenza A virus circulation in a nursery swine barnJuliana B. Ferreira0Helena Grgić1Robert Friendship2Greg Wideman3Éva Nagy4Zvonimir Poljak5Department of Population Medicine, University of GuelphDepartment of Population Medicine, University of GuelphDepartment of Population Medicine, University of GuelphSouth-West Veterinary ServicesDepartment of Pathobiology, University of GuelphDepartment of Population Medicine, University of GuelphAbstract Commercial production of swine often involves raising animals in large groups through the use of multi-stage production systems. In such systems, pigs can experience different degrees of contact with animals of the same or different ages. Population size and degree of contact can greatly influence transmission of endemic pathogens, including influenza A virus (IAV). IAV can display high genetic variability, which can further complicate population-level patterns. Yet, the IAV transmission in large multi-site swine production systems has not been well studied. The objectives of this study were to describe the IAV circulation in a multi-source nursery facility and identify factors associated with infection in nursery pigs. Pigs from five sow herds were mixed in one all-in/all-out nursery barn, with 81 and 75 pigs included in two longitudinal studies. Virus isolation was performed in Madin-Darby canine kidney cells and serology was performed using hemagglutination inhibition assays. Risk factor analysis for virological positivity was conducted using logistic regression and stratified Cox’s regression for recurrent events. In Study 1, at ≈30 days post-weaning, 100% of pigs were positive, with 43.2% of pigs being positive recurrently over the entire study period. In study 2, 48% of pigs were positive at the peak of the outbreak, and 10.7% were positive recurrently over the entire study period. The results suggest that IAV can circulate during the nursery phase in an endemic pattern and that the likelihood of recurrent infections was associated in a non-linear way with the level of heterologous (within-subtype) maternal immunity (p < 0.05). High within-pen intracluster correlation coefficients (> 0.75) were also observed for the majority of sampling times suggesting that pen-level factors played a role in infection dynamics in this study.http://link.springer.com/article/10.1186/s13567-017-0466-x |
| spellingShingle | Juliana B. Ferreira Helena Grgić Robert Friendship Greg Wideman Éva Nagy Zvonimir Poljak Longitudinal study of influenza A virus circulation in a nursery swine barn Veterinary Research |
| title | Longitudinal study of influenza A virus circulation in a nursery swine barn |
| title_full | Longitudinal study of influenza A virus circulation in a nursery swine barn |
| title_fullStr | Longitudinal study of influenza A virus circulation in a nursery swine barn |
| title_full_unstemmed | Longitudinal study of influenza A virus circulation in a nursery swine barn |
| title_short | Longitudinal study of influenza A virus circulation in a nursery swine barn |
| title_sort | longitudinal study of influenza a virus circulation in a nursery swine barn |
| url | http://link.springer.com/article/10.1186/s13567-017-0466-x |
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