Porcine reproductive and respiratory syndrome virus

Abstract

To compare the real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) assays used for the diagnosis of Porcine reproductive and respiratory syndrome virus (PRRSV), a Europe-wide interlaboratory ring trial was conducted. A variety of PRRSV strains including North American (NA) and European (EU) genotype isolates were analyzed by the participants. Great differences regarding qualitative diagnostics as well as analytical sensitivity were observed between the individual RT-qPCR systems, especially when investigating strains from the EU genotype. None of the assays or commercial kits used in the ring trial could identify all different PRRSV strains with an optimal analytical and diagnostic sensitivity. The genetic variability of the PRRSV strains, which is supposed to hinder the diagnostic of the RT-PCR because of mutations at the primer binding sites, was also confirmed by sequencing and subsequent phylogenetic analysis. In summary, a major problem in PRRSV diagnostics by RT-qPCR is false-negative results. To achieve maximum safety in the molecular diagnosis of PRRSV, the combined usage of different assays or kits is highly recommended.

Efficacy and safety of simultaneous vaccination with two modified live virus vaccines against porcine reproductive and respiratory syndrome virus types 1 and 2 in pigs

“…an animal that become positive after being tested negative. The duration of nasal excretion of PRRSV was in line with the previous studies quoted above (7)(8)(9)(10)(11)(12)(13)(14). There is probably a limited risk that these weakly positive animals would transmit the virus horizontally to naïve animals [21], but the persistence of vaccine virus for two-three months after vaccination emphasize the importance of keeping vaccinated animals isolated from naïve animals for a sustained time period prior to mingling.…”

“…The sensitivity of different RT-PCR assays varies considerably and is dependent on a wide range of factors. One crucial determinant of sensitivity is the level of identity between the primer and probe sequences and the isolate to be tested [11]. In order to optimize the sensitivity of the virus detection assays employed, we chose to test for virus by real-time RT-PCR assays that were specifically validated and optimized to recognize the vaccine and challenge strains used in the present study.…”

“…The primers and probe target ORF2. For detection of PRRSV-2, the previously published RT-qPCR ''Kleiboeker mod-1" primers and probe targeting ORF7 3'UTR were used [11].…”

Performance of ELISAs for detection of antibodies against porcine respiratory and reproductive syndrome virus in serum of pigs after PRRSV type 2 live vaccination and challenge

“…Detection of antibodies (Ab) against porcine reproductive and respiratory syndrome virus (PRRSV) is, in addition to a number of different established PCR methods [1, 2], one important tool for the monitoring and surveillance of PRRSV in pig farms [3, 4]. In addition to the cost-effective, simple and rapid analysis by ELISA, alternative methods, such as serum neutralization test, immunofluorescence assay or Western blot are used for special indications [3, 5–7].…”

Heterogeneous antigenic properties of the porcine reproductive and respiratory syndrome virus nucleocapsid

“…PRRSV RVB-581 was a kind gift from Martin Beer (Friedrich-Loeffler-Institut FLI, Greifswald-Insel Riems, Germany). The virus was collected in China in 2008 and isolated in porcine alveolar macrophages and MARC-145 cells at the FLI [50, 51]. PRRSV CReSA-2982 was isolated in MDM and kindly provided by Enric Mateu, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, Spain.…”