Evidence map›Paper›PMID 41530816›Full record

ArticlePorcine health management2026

Influenza A virus infection dynamics in two sow herds and effects of interventions.

Marianne Viuf Agerlin, Lars Erik Larsen, Nicolai Rosager Weber, Mette Fertner, Nicole Bakkegård Goecke, Pia Ryt-Hansen

Abstract read
In one paragraph

Article in Porcine health management, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
  2. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Marianne Viuf AgerlinDepartment of Veterinary Animal Sciences, University of Copenhagen, Dyrlaegevej 88, Frederiksberg, 1870, Denmark. mava@sund.ku.dk.
Lars Erik LarsenDepartment of Veterinary Animal Sciences, University of Copenhagen, Dyrlaegevej 88, Frederiksberg, 1870, Denmark.
Nicolai Rosager WeberDepartment of Veterinary and Quality Services, Danish Agriculture and Food Council F.m.b.A, Axeltorv 3, Copenhagen, Denmark.
Mette FertnerDepartment of Statistics & Analyses, SEGES Innovation P/S, Axeltorv 3, Copenhagen, Denmark.
Nicole Bakkegård GoeckeDepartment of Veterinary Animal Sciences, University of Copenhagen, Dyrlaegevej 88, Frederiksberg, 1870, Denmark.
Pia Ryt-HansenDepartment of Veterinary Animal Sciences, University of Copenhagen, Dyrlaegevej 88, Frederiksberg, 1870, Denmark.

Funding

ICRAD Number 2821ERA24
6 · The paper itself

Abstract

backgroundThe epidemiology of swine influenza A virus (swIAV) has undergone a change from causing mainly epidemic infections to continuous endemic circulation within herds. Several studies have traced the within-herd swIAV transmission pattern. However, studies with more frequent samplings of targeted age groups are needed to increase the current understanding of virus transmission dynamics. In addition, data on the efficacy of different intervention methods for reducing swIAV spread are highly relevant for disrupting endemic swIAV infections. Therefore, this study aimed to investigate the weekly influenza infection dynamics and evaluate subsequent interventions, including vaccination and management changes.

methodTwo batches of pigs in two sow herds (Herd 1 and 2) were sampled with nasal swabs and blood samples from one week of age to the end of the nursery period. In each batch, ten sows were included with each six piglets including three cross-fostered and three of the sows own piglets. Nasal swabs were tested for the presence of swIAV, and blood samples were tested for swIAV antibodies using ELISA and HI-test. In Herd 2, interventions including pre-farrowing vaccination, limited cross-fostering, litter-wise weaning and disinfection of tools and hands were implemented during a second round of sampling in two batches as described above.

resultsIn both herds, an endemic presence of swIAV was observed, with Herd 1 having one circulating swIAV subtype (H1C.2.4N2G) circulating in the farrowing unit and Herd 2 having two swIAV strains (H1C.2.4N2G and H1N1pdm09) circulating both before and after weaning. Maternally derived swIAV antibodies were successfully transferred from sow to piglets, but despite high levels, swIAV infections was observed in the piglets down to one week of age and a lack of subsequent seroconversion was observed. The implementation of pre-farrowing vaccination increased the level of swIAV antibodies in sows and piglets but had no obvious effect on viral shedding and clinical disease.

conclusionsThe endemic state of swIAV infections in sow herds was clearly illustrated in this study along with the difficulties in controlling swIAV through vaccinations and management changes in an environment that favours virus circulation.

Indexed as

ELISA antibody titerHaemagglutination inhibitionInterventionsMaternal antibodyPiglets and weaned pigsSheddingSwIAVSwine influenza A virusWeight

Identifiers

PMID41530816
PMCPMC13081247

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.