Using commercial ELISAs to assess humoral response in sows repeatedly vaccinated with MLV PRRSV.

Vet Rec. 2019 Oct 1. pii: vetrec-2019-105432. doi: 10.1136/vr.105432. [Epub ahead of print]

Using commercial ELISAs to assess humoral response in sows repeatedly vaccinated with modified live porcine reproductive and respiratory syndrome virus.

Díaz I1, Genís-Jorquera B2, Martín-Valls GE3, Mateu E2,3.

Author information

1

IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Bellaterra, Spain ivan.diaz@irta.es.

2

IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Bellaterra, Spain.

3

Departament de Sanitat i Anatomia Animals, Facultat Veterinària, Universitat Autònoma de Barcelona, Bellaterra, Spain.

Abstract

BACKGROUND: 

Sows in breeding herds are often mass vaccinated against porcine reproductive and respiratory syndrome (PRRS) every few months using modified live vaccines (MLV). Field veterinarians repeatedly report that multiple vaccinated sows test negative in ELISA. Obviously, this creates uncertainty when assessing the compliance of vaccination and the status of sows.

METHODS: 

In the present study, four commercial ELISAs were used to assess the serological PRRS status in gilts and sows of three farms that were PRRS MLV vaccinated every four months. Animals were tested before vaccination (BV) and postvaccination (PV). Total and neutralising antibodies and cell-mediated responses were also measured in animals that yielded negative results in all ELISAs.

RESULTS: 

The proportion of seronegative animals BV varied depending on the farm and the ELISA used. When samples were analysed using only one ELISA, a substantial number of negative results obtained BV remained as negative afterwards. Five animals were negative BV and PV with all the examined ELISAs. Those animals also yielded negative results in all the other immunological assays.

CONCLUSION: 

Our findings suggest that the use of ELISA for monitoring multiple PRRS MLV vaccinated sows is very limited due to the variability of the humoral responses and the moderate agreement between tests.

© British Veterinary Association 2019. No commercial re-use. See rights and permissions. Published by BMJ.

KEYWORDS: 

Diagnostics; ELISA; Porcine reproductive and respiratory syndrome (PRRS); Vaccines

PMID:

 

31575761

 

DOI:

 

10.1136/vr.105432