Advanced Research in Porcine Reproductive and Respiratory Syndrome Virus Co-infection With Other Pathogens in Swine

Zhao, Dengshuai; Yang, Bo; Yuan, Xingguo; Shen, Chao; Zhang, Dajun; Shi, Xijuan; Zhang, Ting; Cui, Huimei; Yang, Jinke; Chen, Xuehui; Hao, Yu; Zheng, Haixue; Zhang, Keshan; Liu, Xiangtao

doi:10.3389/fvets.2021.699561

Cited by 29 publications

(19 citation statements)

References 107 publications

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“…In all three farms, co-infections with common respiratory bacteria or other viruses were detected. These often occur in PRRS outbreaks and can exacerbate the clinical outcome [ 30 ], as it was observed on the farm of isolate GER18-258 where Streptococcus suis caused swollen joints in nursery pigs.…”

Section: Discussionmentioning

confidence: 99%

A Conserved Stem-Loop Structure within ORF5 Is a Frequent Recombination Hotspot for Porcine Reproductive and Respiratory Syndrome Virus 1 (PRRSV-1) with a Particular Modified Live Virus (MLV) Strain

Mötz

Stadler

Kreutzmann

et al. 2023

Viruses

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The emergence of recombinant PRRSV strains has been observed for more than a decade. These recombinant viruses are characterized by a genome that contains genetic material from at least two different parental strains. Due to the advanced sequencing techniques and a growing number of data bank entries, the role of PRRSV recombinants has become increasingly important since they are sometimes associated with clinical outbreaks. Chimeric viruses observed more recently are products of PRRSV wild-type and vaccine strains. Here, we report on three PRRSV-1 isolates from geographically distant farms with differing clinical manifestations. A sequencing and recombination analysis revealed that these strains are crossovers between different wild-type strains and the same modified live virus vaccine strain. Interestingly, the recombination breakpoint of all analyzed isolates appears at the beginning of open reading frame 5 (ORF5). RNA structure predictions indicate a conserved stem loop in close proximity to the recombination hotspot, which is a plausible cause of a polymerase template switch during RNA replication. Further research into the mechanisms of the stem loop is needed to help understand the PRRSV recombination process and the role of MLVs as parental strains.

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Section: Discussionmentioning

confidence: 99%

A Conserved Stem-Loop Structure within ORF5 Is a Frequent Recombination Hotspot for Porcine Reproductive and Respiratory Syndrome Virus 1 (PRRSV-1) with a Particular Modified Live Virus (MLV) Strain

Mötz

Stadler

Kreutzmann

et al. 2023

Viruses

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“…[reviewed in Saade et al (2020) and Zhao et al (2021)] but, in general, the costs associated with the disease are significant for the affected farms (Nieuwenhuis et al, 2012;Holtkamp et al, 2013;Renken et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Infection dynamics, transmission, and evolution after an outbreak of porcine reproductive and respiratory syndrome virus

Clilverd

Martín‐Valls²,

Li³

et al. 2023

Front. Microbiol.

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The present study was aimed at describing the infection dynamics, transmission, and evolution of porcine reproductive and respiratory syndrome virus (PRRSV) after an outbreak in a 300-sow farrow-to-wean farm that was implementing a vaccination program. Three subsequent batches of piglets (9–11 litters/batch) were followed 1.5 (Batch 1), 8 (Batch 2), and 12 months after (Batch 3) from birth to 9 weeks of age. The RT-qPCR analysis showed that shortly after the outbreak (Batch 1), one third of sows were delivering infected piglets and the cumulative incidence reached 80% by 9 weeks of age. In contrast, in Batch 2, only 10% animals in total got infected in the same period. In Batch 3, 60% litters had born-infected animals and cumulative incidence rose to 78%. Higher viral genetic diversity was observed in Batch 1, with 4 viral clades circulating, of which 3 could be traced to vertical transmission events, suggesting the existence of founder viral variants. In Batch 3 though only one variant was found, distinguishable from those circulating previously, suggesting that a selection process had occurred. ELISA antibodies at 2 weeks of age were significantly higher in Batch 1 and 3 compared to Batch 2, while low levels of neutralizing antibodies were detected in either piglets or sows in all batches. In addition, some sows present in Batch 1 and 3 delivered infected piglets twice, and the offspring were devoid of neutralizing antibodies at 2 weeks of age. These results suggest that a high viral diversity was featured at the initial outbreak followed by a phase of limited circulation, but subsequently an escape variant emerged in the population causing a rebound of vertical transmission. The presence of unresponsive sows that had vertical transmission events could have contributed to the transmission. Moreover, the records of contacts between animals and the phylogenetic analyses allowed to trace back 87 and 47% of the transmission chains in Batch 1 and 3, respectively. Most animals transmitted the infection to 1–3 pen-mates, but super-spreaders were also identified. One animal that was born-viremic and persisted as viremic for the whole study period did not contribute to transmission.

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“…The disease, porcine reproductive and respiratory syndrome (PRRS), caused by PPRSV, is considered a major viral disease threatening the swine industry worldwide [ 2 , 3 ]. The clinical symptoms of PRRS in pigs are complex, which mainly depend on the infecting lineage, development stage and immune status of the pigs, and environmental conditions [ 4 ]. The PRRSV genome is approximately 15 kb in length, consisting of more than ten open reading frames (ORFs) (ORF1a, ORF1b, ORF2a, ORF2b, ORF3, ORF4, ORF5a, ORF5, ORF6, and ORF7) [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

Epidemiology and Genetic Characteristics of Porcine Reproductive and Respiratory Syndrome Virus in the Hunan and Hebei Provinces of China

Zhai

Yu²,

Zhang

et al. 2023

Veterinary Sciences

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Porcine reproductive and respiratory syndrome virus (PRRSV) is a significant threat to the pig industry in China. However, the epidemiological characteristics of PRRSV after the outbreak of African swine fever in China were not thoroughly investigated. In the present study, the serological and epidemiological investigations of PRRSV in pigs from the Hunan and Hebei provinces of China were assessed. The results showed that 73.12% (95% CI 71.74–74.49) of pigs were positive for PRRSV-special antibody by enzyme-linked immunosorbent assay. Out of 5799 samples, 482 (8.31%, 95% CI 7.60–9.02) samples were positive for PRRSV nucleic acids. The positive rates of PRRSV in healthy pigs from farms and slaughterhouses were 2.27% (47/2072) and 7.70% (217/2818), which were lower than that in diseased pigs (23.98%, 218/909). Furthermore, the full-length OFR5 gene sequences of 43 PRRSV strains were sequenced and analysed. Phylogenetic analysis revealed that 43 isolates were classified into three lineages, namely lineage 1 (n = 24), lineage 8 (n = 15), and lineage 3 (n = 4). Lineage 1 could be further divided into sublineage 1.5 (n = 2) and sublineage 1.8 (n = 22), and lineage 8 was classified into sublineage 8.1 (n = 3) and sublineage 8.7 (n = 12). Collectively, our findings revealed the severe prevalence of PRRSV in the Hunan and Hebei provinces, where sublineage 1.8 and sublineage 8.7 predominated. The present study provides the update information of the epidemiological and genetic characteristics of PRRSV in the investigated regions, which will be beneficial for PRRS control.

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Advanced Research in Porcine Reproductive and Respiratory Syndrome Virus Co-infection With Other Pathogens in Swine

Cited by 29 publications

References 107 publications

A Conserved Stem-Loop Structure within ORF5 Is a Frequent Recombination Hotspot for Porcine Reproductive and Respiratory Syndrome Virus 1 (PRRSV-1) with a Particular Modified Live Virus (MLV) Strain

A Conserved Stem-Loop Structure within ORF5 Is a Frequent Recombination Hotspot for Porcine Reproductive and Respiratory Syndrome Virus 1 (PRRSV-1) with a Particular Modified Live Virus (MLV) Strain

Infection dynamics, transmission, and evolution after an outbreak of porcine reproductive and respiratory syndrome virus

Epidemiology and Genetic Characteristics of Porcine Reproductive and Respiratory Syndrome Virus in the Hunan and Hebei Provinces of China

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