The contribution of integrated and non-integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in Italy

Abstract Porcine reproductive and respiratory syndrome (PRRS) is a global challenge for swine production. Due to its high variability and limited cross-protection, immune-based control measures are only partially effective, emphasizing the critical role of biosecurity. A prior study on Italy’s large...

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Main Authors: M. Ustulin, D. Vio, C. Targhetta, C. Zanon, L. Ferino, G. Faustini, G. Franzo
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-13388-3
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author M. Ustulin
D. Vio
C. Targhetta
C. Zanon
L. Ferino
G. Faustini
G. Franzo
author_facet M. Ustulin
D. Vio
C. Targhetta
C. Zanon
L. Ferino
G. Faustini
G. Franzo
author_sort M. Ustulin
collection DOAJ
description Abstract Porcine reproductive and respiratory syndrome (PRRS) is a global challenge for swine production. Due to its high variability and limited cross-protection, immune-based control measures are only partially effective, emphasizing the critical role of biosecurity. A prior study on Italy’s largest integrated pig production company demonstrated the effectiveness of hierarchical organization in separating pig flows but, through biostatistical estimations, highlighted vulnerabilities, particularly the role of non-integrated farms in introducing new variants into the integrated system. Over 500 PRRSV sequences from integrated and non-integrated farms in central-northern Italy were analysed in the present study using phylogenetic, phylodynamic, and phylogeographic approaches. Two main PRRSV clades were identified circulating in both systems, with non-integrated farms hosting a broader viral population. The migration rate of PRRSV from non-integrated to integrated systems was found to be 2–10 times higher than the reverse, depending on the clade. Geographical migration patterns and environmental factors influencing viral dispersal were evaluated. Despite being located in the same geographical areas, non-integrated farms exhibited higher viral dispersal speeds, marked by bursts over time. Although some differences in geographical persistence and dispersal risk factors were observed among clades and categories, road networks and pig population density were the most important and shared determinants. These findings confirm the critical role of non-integrated farms in PRRSV epidemiology, posing a risk to integrated systems due to their distinct persistence and spread determinants. The study underscores the necessity for regional collaboration and information sharing to improve infection control and reduce viral recirculation between different productive systems.
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spelling doaj-art-76e4bd9e8347457e9537229d5b3e35c72025-08-20T03:05:18ZengNature PortfolioScientific Reports2045-23222025-08-0115111210.1038/s41598-025-13388-3The contribution of integrated and non-integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in ItalyM. Ustulin0D. Vio1C. Targhetta2C. Zanon3L. Ferino4G. Faustini5G. Franzo6Laboratory of Swine Pathology and Welfare, Istituto Zooprofilattico Sperimentale Delle VenezieLaboratory of Swine Pathology and Welfare, Istituto Zooprofilattico Sperimentale Delle VenezieLaboratory of Swine Pathology and Welfare, Istituto Zooprofilattico Sperimentale Delle VenezieLaboratory of Swine Pathology and Welfare, Istituto Zooprofilattico Sperimentale Delle VenezieLaboratory of Swine Pathology and Welfare, Istituto Zooprofilattico Sperimentale Delle VenezieDepartment of Animal Medicine, Production and Health (MAPS), University of PaduaDepartment of Animal Medicine, Production and Health (MAPS), University of PaduaAbstract Porcine reproductive and respiratory syndrome (PRRS) is a global challenge for swine production. Due to its high variability and limited cross-protection, immune-based control measures are only partially effective, emphasizing the critical role of biosecurity. A prior study on Italy’s largest integrated pig production company demonstrated the effectiveness of hierarchical organization in separating pig flows but, through biostatistical estimations, highlighted vulnerabilities, particularly the role of non-integrated farms in introducing new variants into the integrated system. Over 500 PRRSV sequences from integrated and non-integrated farms in central-northern Italy were analysed in the present study using phylogenetic, phylodynamic, and phylogeographic approaches. Two main PRRSV clades were identified circulating in both systems, with non-integrated farms hosting a broader viral population. The migration rate of PRRSV from non-integrated to integrated systems was found to be 2–10 times higher than the reverse, depending on the clade. Geographical migration patterns and environmental factors influencing viral dispersal were evaluated. Despite being located in the same geographical areas, non-integrated farms exhibited higher viral dispersal speeds, marked by bursts over time. Although some differences in geographical persistence and dispersal risk factors were observed among clades and categories, road networks and pig population density were the most important and shared determinants. These findings confirm the critical role of non-integrated farms in PRRSV epidemiology, posing a risk to integrated systems due to their distinct persistence and spread determinants. The study underscores the necessity for regional collaboration and information sharing to improve infection control and reduce viral recirculation between different productive systems.https://doi.org/10.1038/s41598-025-13388-3PRRSVPhylodynamicPhylogeographyEpidemiologySpreading factors
spellingShingle M. Ustulin
D. Vio
C. Targhetta
C. Zanon
L. Ferino
G. Faustini
G. Franzo
The contribution of integrated and non-integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in Italy
Scientific Reports
PRRSV
Phylodynamic
Phylogeography
Epidemiology
Spreading factors
title The contribution of integrated and non-integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in Italy
title_full The contribution of integrated and non-integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in Italy
title_fullStr The contribution of integrated and non-integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in Italy
title_full_unstemmed The contribution of integrated and non-integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in Italy
title_short The contribution of integrated and non-integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in Italy
title_sort contribution of integrated and non integrated pig farms to epidemiological dynamics of porcine reproductive and respiratory syndrome virus in italy
topic PRRSV
Phylodynamic
Phylogeography
Epidemiology
Spreading factors
url https://doi.org/10.1038/s41598-025-13388-3
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