Emergence of highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) in medium-scale swine farms in southeastern Cambodia

Tornimbene, Barbara; Frossard, Jean-Pierre; Chhim, V.; Sorn, San; Guitian, Javier; Drew, Trevor W.

doi:10.1016/j.prevetmed.2014.08.009

Cited by 20 publications

(13 citation statements)

References 36 publications

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“…Since the first outbreak of HP-PRRSV infection in China in 2006, this disease spread subsequently to South East Asian countries including Vietnam and the Philippines in 2007, in Thailand in 2008, and Cambodia and Laos in 2010(An et al, 2011Ni et al, 2012;Tornimbene et al, 2014;Jantafong et al, 2015). Vaccination is now considered to be one of the main strategies to control the HP-PRRSV.…”

Section: Introductionmentioning

confidence: 99%

Comparison of two genetically distant type 2 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccines against Vietnamese highly pathogenic PRRSV

Tien

Park

Choi

et al. 2015

Veterinary Microbiology

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Section: Introductionmentioning

confidence: 99%

Comparison of two genetically distant type 2 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccines against Vietnamese highly pathogenic PRRSV

Tien

Park

Choi

et al. 2015

Veterinary Microbiology

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“…HPPRRS viruses have been identified within both genotypes (Hu et al., ). Phylogenetic analyses revealed that the viruses isolated from many south‐east Asian countries are highly related to the HP‐PRRSV strains in China but variations are known to exist as they exhibit different virulence (Feng et al., ; Ni et al., ; Rajkhowa et al., ; Tornimbene et al., ). The emergence of PRRSV strains of varying virulence has been reported on several occasions within European type 1 lineage viruses, with classical type 2 strains in the US and Chinese atypical PRRSV, suggesting these viruses continue to evolve due to repeated recombination and accumulation of mutations (Brockmeier et al., ; Stadejek et al., ; Tian et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…HPPRRS infections are characterized by high fever, petechiae, erythematous blanching rash and interstitial pneumonia, splenic infarct, haemorrhages in kidneys, etc., with mortality rate up to 100% in pre‐weaned piglets, 10%–20% in mature pigs (Han, Zhou, Ge, Guo, & Yang, ; Li, He et al., ). Subsequent outbreaks caused by HP‐PRRSV were reported in other parts of Asia including Vietnam, Laos, Philippines and Cambodia with varying pathogenicity (Feng et al., ; Ni et al., ; Tornimbene et al., ). It is well known that most of the field outbreaks of PRRSV infections are complicated with other viral and bacterial infections (Han et al., ).…”

Section: Introductionmentioning

confidence: 99%

Pathogenic characterization of porcine reproductive and respiratory syndrome virus of Indian origin in experimentally infected piglets

Senthilkumar

Rajukumar

Kumar

et al. 2018

Transbound Emerg Dis

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Porcine reproductive and respiratory syndrome (PRRS) is an economically important transboundary viral disease of pigs confronting the swine industry worldwide. This study was aimed to assess the pathogenic potential of PRRS virus belonging to genotype 2 that emerged in India in 2013. Nine 6-week-old piglets were inoculated intranasally with 2 × 10 TCID /ml of PRRSV (Ind-297221/2013). Three piglets were kept as uninfected controls. Blood and nasal swabs were collected daily up to 7 days post-infection (dpi) and on alternate days subsequently. Piglets were necropsied for tissue sample collection either on death or after euthanasia on 7, 14 or 21 dpi (one uninfected control and three PRRSV-infected piglets per interval). The virus caused high fever, typical blue ear, weight loss, respiratory distress, diarrhoea and leucopenia between 2 and 8 dpi. Two infected piglets died (on 3 and 17 dpi) during the course of study. The presence of virus in serum and nasal secretion was observed up to 19 and 17 dpi, respectively, with the maximum load between 4 and 7 dpi. Seroconversion started 6 dpi and the mean PRRSV antibody titre reached up to 640 by 21 dpi. Virus load was highest in tonsils at all the intervals, whereas in spleen and lymph nodes load was higher in later intervals. Major microscopic lesions in PRRSV-infected piglets included moderate to severe interstitial pneumonia, lymphoid depletion in tonsils and lymph nodes (cystic), thymic atrophy, reactive hyperplasia followed by lymphoid depletion in spleen. PRRSV antigen was consistently demonstrated by immunoperoxidase test in the lungs, spleen, tonsils and lymph nodes. Antigen distribution was more widespread on 7 and 14 dpi than on 21 dpi. The findings establish that the Indian PRRSV is highly pathogenic to piglets.

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“…staggering economic losses (4)(5)(6). It is estimated to cost U.S. pork producers 500 to 600 million dollars per year, with even greater costs in Asia (7)(8)(9)(10)(11).…”

mentioning

confidence: 99%

The nsp2 Hypervariable Region of Porcine Reproductive and Respiratory Syndrome Virus Strain JXwn06 Is Associated with Viral Cellular Tropism to Primary Porcine Alveolar Macrophages

Song

Gao

Kong

et al. 2019

J Virol

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Porcine reproductive and respiratory syndrome virus (PRRSV) poses a major threat to global pork production and has been notorious for its rapid genetic evolution in the field. The nonstructural protein 2 (nsp2) replicase protein represents the fastest evolving region of PRRSV, but the underlying biological significance has remained poorly understood. By deletion mutagenesis, we discovered that the nsp2 hypervariable region plays an important role in controlling the balance of genomic mRNA and a subset of subgenomic mRNAs. More significantly, we revealed an unexpected link of the nsp2 hypervariable region to viral tropism. Specifically, a mutant of the Chinese highly pathogenic PRRSV strain JXwn06 carrying a deletion spanning nsp2 amino acids 323 to 521 (nsp2Δ323–521) in its hypervariable region was found to lose infectivity in primary porcine alveolar macrophages (PAMs), although it could replicate relatively efficiently in the supporting cell line MARC-145. Consequently, this mutant failed to establish an infection in piglets. Further dissection of the viral life cycle revealed that the mutant had a defect (or defects) lying in the steps between virus penetration and negative-stranded RNA synthesis. Taken together, our results reveal novel functions of nsp2 in the PRRSV life cycle and provide important insights into the mechanisms of PRRSV RNA synthesis and cellular tropism. IMPORTANCE The PRRSV nsp2 replicase protein undergoes rapid and broad genetic variations in its middle region in the field, but the underlying significance has remained enigmatic. Here, we demonstrate that the nsp2 hypervariable region not only plays an important regulatory role in maintaining the balance of different viral mRNA species but also regulates PRRSV tropism to primary PAMs. Our results reveal novel functions for PRRSV nsp2 and have important implications for understanding the mechanisms of PRRSV RNA synthesis and cellular tropism.

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Emergence of highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) in medium-scale swine farms in southeastern Cambodia

Cited by 20 publications

References 36 publications

Comparison of two genetically distant type 2 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccines against Vietnamese highly pathogenic PRRSV

Comparison of two genetically distant type 2 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccines against Vietnamese highly pathogenic PRRSV

Pathogenic characterization of porcine reproductive and respiratory syndrome virus of Indian origin in experimentally infected piglets

The nsp2 Hypervariable Region of Porcine Reproductive and Respiratory Syndrome Virus Strain JXwn06 Is Associated with Viral Cellular Tropism to Primary Porcine Alveolar Macrophages

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