Quantitative TaqMan® RT-PCR for the detection and differentiation of European and North American strains of porcine reproductive and respiratory syndrome virus

2001 ◽  
Vol 98 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Christoph Egli ◽  
Barbara Thür ◽  
Luzia Liu ◽  
Martin A Hofmann
2018 ◽  
Vol 16 (1) ◽  
pp. 51-57
Author(s):  
Nguyễn Thị Nga ◽  
Hà Thị Thu ◽  
Nguyễn Thị Hoa ◽  
Vũ Thị Hiền ◽  
Trần Thị Thu Hiền ◽  
...  

The porcine reproductive and respiratory syndrome virus (PRRSV) attenuated strain Hanvet1.VN has been developed by the Pharmaceutical and Veterinary Material J.S.C (HANVET) by passaging HY-2010 strain on MARC-145 cells for 80 passages and used for PRRS vaccine production. In this study, we sequenced and analyzed the whole genome of the attenuated Hanvet1.VN strain. The total RNA was extracted from the Hanvet1.VN strain, RT-PCR was used for amplification of 15 separate segments of the whole genome. The amplified segments were cloned into the pCR2.1 vector and sequenced by Sanger sequencing. The sequences were analyzed with BioEdit and DNA Star Software. The results showed that, GP5 of the Hanvet1.VN attenuated strain had 100% identity in amino acid (aa) sequences with one of the pathogenic Vietnamese strain isolated in Quang Nam Province and had 98% identity with that of the Chinese 07NM strain. However, the identity of aa sequence of the Hanvet1.VN GP5 was much lower in the comparison with GP5 of VR2332, and it was only 87%. The MP and NP proteins were highly conserved compared with pathogenic strains circulating in Vietnam (07QN) and China (07NM) (99-100%, respectively). The other eight proteins of the Hanvet1.VN strain showed changes from 1.2% in NP1a to 3.9% in GP2 compared with the 07QN strain. However, the aa identity of all Hanvet1.VN proteins were very low when compared with proteins of PRRSV type II strain (North American strain, VR2332), ranged from 86.25% to 97.7%. Our results showed that the Hanvet1.VN attenuated vaccine strain had protective immunogenicity similar to that strain circulating in Vietnam closely related to a strain from China but different from the type II North American strain VR2332. Hence, for importing PRRSV vaccine, especially from American or Europe Countries, antigenic compatibility of the PRRSV vaccine and strains circulating in Vietnam should be concerned in PRRSV vaccine production.


2001 ◽  
Vol 82 (11) ◽  
pp. 2615-2620 ◽  
Author(s):  
Joke J. F. A. van Vugt ◽  
Torben Storgaard ◽  
Martin B. Oleksiewicz ◽  
Anette Bøtner

Two types of porcine reproductive and respiratory syndrome virus (PRRSV) exist, a North American type and a European type. The co-existence of both types in some countries, such as Denmark, Slovakia and Canada, creates a risk of inter-type recombination. To evaluate this risk, cell cultures were co-infected with either a North American and a European type of PRRSV or two diverse types of European isolate. Subsequently, an approximately 600 bp region of the PRRSV genome was tested for recombination by quantitative real-time RT–PCR. Between 0·1 and 2·5% RNA recombination was found between the European isolates, but no recombination was detected between the European and North American types. Calculation of the maximum theoretical risk of European–American recombination, based on the sensitivity of the RT–PCR system, revealed that RNA recombination between the European and North American types of PRRSV is at least 10000 times less likely to occur than RNA recombination between diverse European isolates.


2005 ◽  
Vol 17 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Steven B. Kleiboeker ◽  
Susan K. Schommer ◽  
Sang-Myeong Lee ◽  
Sandy Watkins ◽  
Wayne Chittick ◽  
...  

Porcine reproductive and respiratory syndrome (PRRS) is 1 of the most economically important diseases of swine. Detection of the etiologic agent, PRRS virus (PRRSV), represents a diagnostic challenge due to the heterogeneity of field isolates as well as the propensity for swine to develop persistent infection in which virus is difficult to detect. Recently European (EU) lineage PRRSV isolates, which are genetically divergent from North American (NA) isolates, have been introduced into NA swine further complicating efforts to diagnose this disease. In this study, real-time ( TaqMan) reverse transcriptase (RT)–PCR assays were developed for multiplex detection, differentiation, and quantification of NA and EU PRRSV field isolates. Oligonucleotide primers and dual-labeled probes were selected from conserved regions of open-reading frame 7 and the 3'-untranslated region. The real-time RT-PCR assays described for the NA or EU genotype of PRRSV detected viral RNA from 83/83 strains (74 NA; 9 EU) previously isolated by cell culture between 1992 and 2003. The analytical sensitivity of both assays was consistently found to be less than a single TCID50, which corresponded to 5–10 RNA molecules, and was not significantly reduced when the reactions were performed in a multiplex format. When performing multiplex reactions, sensitive detection was possible even when 1 viral RNA concentration was up to 5,000-fold higher than the second. The diagnostic sensitivity and specificity of the multiplex reaction was found to be at a minimum equivalent to that of both nested RT-PCR and virus isolation.


2014 ◽  
Vol 201 ◽  
pp. 79-85 ◽  
Author(s):  
Michele Drigo ◽  
Giovanni Franzo ◽  
Ilaria Belfanti ◽  
Marco Martini ◽  
Alessandra Mondin ◽  
...  

2004 ◽  
Vol 34 (2) ◽  
pp. 449-455 ◽  
Author(s):  
Janice Reis Ciacci-Zanella ◽  
Cristiano Trombetta ◽  
Ildara Vargas ◽  
Denise Euclydes Mariano da Costa

This report describes the first prevalence of antibodies and experimental inoculation of suspected samples of porcine reproductive and respiratory syndrome virus (PRRSV) from ELISA positive pigs from swine herds in Brazil. Based on the hypothesis that this agent is present in swine herds worldwide, the objective of this work was to establish a diagnostic methodology and to investigate the occurrence of PRRSV in Brazilian swine herds. Fifty-four swine herds, the total number which imported genetic material (live pigs or swine semen) from countries where PRRS was endemic from 1990 to December 2000, from eight Brazilian States all included in this study. The sampling used was such as to detect a prevalence of infection of 5%, with a confidence level of 95%. A total of 3785 serum samples were tested for PRRSV antibodies by ELISA. Following the ELISA test, which was performed with two different commercial kits, all serum positive pigs were retested, examined and additional materials were collected. Viral isolation in permissive tissue culture cells and swine bioassays were performed. Additionally, reverse transcriptase polymerase chain reaction (RT-PCR) and nested RT-PCR were also performed. We could not demonstrate the presence of PRRSV or RNA of PRRSV by viral isolation or RT-PCR (or nested RT-PCR), respectively in all of the analyzed samples. Furthermore, the pigs inoculated with PRRSV suspicion samples did not seroconvert nor produce characteristic PRRS lesions in the swine bioassay. Thus, our results indicate no evidence of PRRSV in the samples analyzed from swine herds in this study.


Author(s):  
Clinton R Paden ◽  
Ying Tao ◽  
Krista Queen ◽  
Jing Zhang ◽  
Yan Li ◽  
...  

AbstractSARS-CoV-2 recently emerged, resulting a global pandemic. Rapid genomic information is critical to understanding transmission and pathogenesis. Here, we describe validated protocols for generating high-quality full-length genomes from primary samples. The first employs multiplex RT-PCR followed by MinION or MiSeq sequencing. The second uses singleplex, nested RT-PCR and Sanger sequencing.


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