Vet Microbiol. 2016 Aug 30;192:10-20. doi: 10.1016/j.vetmic.2016.06.006. Epub 2016 Jun 16.

Factors associated with herd-level PRRSV infection and age-time to seroconversion in farrow-to-finish herds.

Fablet C1, Marois-Créhan C2, Grasland B3, Simon G4, Rose N5.

Author information

1

Agence Nationale de Sécurité Sanitaire (Anses), Unité Epidémiologie et Bien-Etre du Porc, B.P. 53, 22440 Ploufragan, France; Université Bretagne Loire, Ploufragan, France. Electronic address: christelle.fablet@anses.fr.

2

Agence Nationale de Sécurité Sanitaire (Anses), Unité Mycoplasmologie Bactériologie, B.P. 53, 22440 Ploufragan, France; Université Bretagne Loire, Ploufragan, France.

3

Agence Nationale de Sécurité Sanitaire (Anses), Unité Génétique Virale et Biosécurité, B.P. 53, 22440 Ploufragan, France; Université Bretagne Loire, Ploufragan, France.

4

Agence Nationale de Sécurité Sanitaire (Anses), Unité Virologie Immunologie Porcines, B.P. 53, 22440 Ploufragan, France; Université Bretagne Loire, Ploufragan, France.

5

Agence Nationale de Sécurité Sanitaire (Anses), Unité Epidémiologie et Bien-Etre du Porc, B.P. 53, 22440 Ploufragan, France; Université Bretagne Loire, Ploufragan, France.

Abstract

Factors associated with porcine reproductive and respiratory syndrome virus (PRRSV) infection were investigated in 109 herds. Serums from four batches of pigs (4, 10, 16 and 22 weeks, 15 pigs/batch) were tested by ELISA for PRRSV antibodies. Infection by Mycoplasma hyopneumoniae (Mhp), Actinobacillus pleuropneumoniae, H1N1 and H1N2 swine influenza A viruses (swIAV) and PCV2 were detected by specific serological or PCR tests. Data related to herd characteristics, biosecurity, management housing and climatic conditions were collected during a herd visit. Factors associated with the herd's PRRSV seropositive status were identified by logistic regression. Large herd size, the lack of disinsectisation in the gestation facilities, on-farm semen collection, a short time-period for gilt quarantine and a low temperature setpoint for the ventilation controller in the fattening room significantly increased the odds of a herd being seropositive for PRRSV. Infection by Mhp and H1N2 swIAV were associated with a PRRSV seropositive status. A Cox proportional hazards model was used to identify the factors associated with the age-time to seroconversion in infected herds. Joint housing for the gilts and sows when lactating, a large nursery pen, a small number of pens per fattening room and lack of all-in all-out management in the fattening section significantly reduced the age-time to seroconversion. A small range of temperatures controlling ventilation rate in the nursery room was also associated with time to PRRSV seroconversion. Infection by Mhp and a high PCV2 infection pressure were associated with a shorter time to seroconversion. Biosecurity measures minimising the risk of introducing PRRSV into the herd, management practices reducing contacts between animals from different batches and within batches and favourable climatic conditions should be implemented to better control PRRSV infection. 

Copyright © 2016. Published by Elsevier B.V.

KEYWORDS: 

Logistic regression; PRRS; Risk factors; Survival analysis

PMID:

 

27527759

 

DOI:

 

10.1016/j.vetmic.2016.06.006