Seroprevalence of Swine Influenza A Virus (swIAV) in Commercial Pig Farms in Greece (2023-2026): Age, Regional and Temporal Patterns.
5 affiliations
- 1Clinic of Medicine, Faculty of Veterinary Medicine, University of Thessaly, 43100 Karditsa, Greece.
- 2Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
- 3Department of Poultry Diseases, Faculty of Veterinary Medicine, University of Thessaly, 43100 Karditsa, Greece.
- 4Swine Technical Support, Hipra Hellas SA, 10441 Athens, Greece.
- 5Department of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, 43100 Karditsa, Greece.
Abstract
Swine influenza A virus (swIAV) is an endemic respiratory pathogen of pigs with zoonotic relevance. We analysed retrospective serological data from routine diagnostic submissions (January 2023-May 2026) to a single laboratory, comprising 2003 sera from 66 reports on 44 commercial farrow-to-finish farms in seven regions of mainland Greece, tested with a nucleoprotein ELISA that cannot distinguish vaccine-, maternally, or infection-derived antibodies. Overall seroprevalence was 46.4% (929/2003; farm-clustered 95% CI 39.1-53.8%); at least one seropositive animal was found in 51 of 61 farm-years and in 36 of 44 farms. Seroprevalence differed by production stage (p < 0.001): it was highest in multiparous sows (75.9%) and suckling piglets (70.7%), both likely influenced by sow vaccination and maternally derived antibodies, intermediate in gilts (46.0%) and nursery pigs (38.6%), and lowest in growers (24.8%) and finishers (24.0%), in which antibodies indicate prior exposure rather than current circulation. No consistent temporal trend was detected, although some adjusted models suggested higher seroprevalence in 2025-2026. Regional seroprevalence ranged from 10.1% (Thessaly) to 61.0% (West Greece); the association was significant with the standard but not the bias-reduced cluster-robust estimator (p = 0.014 and p = 0.39) and persisted after adjustment for year and stage, but it rests on few farms per region and is considered exploratory. As a convenience sample of diagnostic submissions, these data provide descriptive rather than nationally representative estimates and support the addition of molecular, subtype-level surveillance.
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BibTeX
@article{papatsiros2026seroprevalence,
title = {{Seroprevalence of Swine Influenza A Virus (swIAV) in Commercial Pig Farms in Greece (2023-2026): Age, Regional and Temporal Patterns.}},
author = {Vasileios G Papatsiros and Georgios I Papakonstantinou and Constantinos S Kyriakis and Dimitrios C Sakkas and Zoi Prentza and Ilias Terzidis and Konstantinos Koutoulis and Charalambos Billinis},
journal = {Veterinary sciences},
year = {2026},
month = oct,
doi = {10.3390/vetsci13101041},
url = {https://europepmc.org/article/MED/42944137},
note = {CC BY},
}
RIS
TY - JOUR
TI - Seroprevalence of Swine Influenza A Virus (swIAV) in Commercial Pig Farms in Greece (2023-2026): Age, Regional and Temporal Patterns.
AU - Vasileios G Papatsiros
AU - Georgios I Papakonstantinou
AU - Constantinos S Kyriakis
AU - Dimitrios C Sakkas
AU - Zoi Prentza
AU - Ilias Terzidis
AU - Konstantinos Koutoulis
AU - Charalambos Billinis
PY - 2026
DA - 2026/10/02
JO - Veterinary sciences
DO - 10.3390/vetsci13101041
UR - https://europepmc.org/article/MED/42944137
AB - Swine influenza A virus (swIAV) is an endemic respiratory pathogen of pigs with zoonotic relevance. We analysed retrospective serological data from routine diagnostic submissions (January 2023-May 2026) to a single laboratory, comprising 2003 sera from 66 reports on 44 commercial farrow-to-finish farms in seven regions of mainland Greece, tested with a nucleoprotein ELISA that cannot distinguish vaccine-, maternally, or infection-derived antibodies. Overall seroprevalence was 46.4% (929/2003; farm-clustered 95% CI 39.1-53.8%); at least one seropositive animal was found in 51 of 61 farm-years and in 36 of 44 farms. Seroprevalence differed by production stage (p < 0.001): it was highest in multiparous sows (75.9%) and suckling piglets (70.7%), both likely influenced by sow vaccination and maternally derived antibodies, intermediate in gilts (46.0%) and nursery pigs (38.6%), and lowest in growers (24.8%) and finishers (24.0%), in which antibodies indicate prior exposure rather than current circulation. No consistent temporal trend was detected, although some adjusted models suggested higher seroprevalence in 2025-2026. Regional seroprevalence ranged from 10.1% (Thessaly) to 61.0% (West Greece); the association was significant with the standard but not the bias-reduced cluster-robust estimator (p = 0.014 and p = 0.39) and persisted after adjustment for year and stage, but it rests on few farms per region and is considered exploratory. As a convenience sample of diagnostic submissions, these data provide descriptive rather than nationally representative estimates and support the addition of molecular, subtype-level surveillance.
SN - 2306-7381
ER -