Two Commercial Type 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)‐Modified Live Vaccines Reduce Seminal Shedding of Type 1 PRRSV but not Type 2 PRRSV in Infected Boars

&NA; The objective of this study was to compare the effects of two commercial type 1 porcine reproductive and respiratory syndrome virus (PRRSV)‐modified live vaccines on type 1 and type 2 PRRSV shedding in the semen of experimentally infected boars. Upon challenge with PRRSV, unvaccinated boars exhibited an increase in daily rectal temperature (39.4–39.7°C). Vaccination of boars with type 1 PRRSV significantly reduced the amount of type 1 PRRSV load in blood and semen after challenge with type 1 PRRSV, but barely reduced the amount of type 2 PRRSV load in blood and semen after the type 2 PRRSV challenge. There were no significant differences in the reduction of viremia and seminal shedding of type 1 and type 2 PRRSV between the two commercial vaccines. The seminal shedding of PRRSV is independent of viremia. The reduction of type 1 PRRSV seminal shedding coincided with the appearance of type 1 PRRSV‐specific interferon‐γ secreting cells (IFN‐γ‐SC) in vaccinated type 1 PRRSV‐challenged boars. The frequencies of type 1 PRRSV‐specific IFN‐γ‐SC induced by type 1 PRRSV vaccine are relatively high compared to type 2 PRRSV‐specific IFN‐γ‐SC induced by the same vaccine which may explain why type 1 PRRSV vaccine is more effective in reducing seminal shedding of type 1 PRRSV when compared to type 2 PRRSV in vaccinated challenged boars. These results provide clinical information on how to reduce seminal shedding of type 1 PRRSV in boars using type 1 PRRSV‐modified live vaccine.

[1]  G. Schüpbach-Regula,et al.  Coxiella burnetii Infections in Small Ruminants and Humans in Switzerland , 2017, Transboundary and emerging diseases.

[2]  C. Nathues,et al.  An Outbreak of Porcine Reproductive and Respiratory Syndrome Virus in Switzerland Following Import of Boar Semen. , 2016, Transboundary and emerging diseases.

[3]  C. Chae,et al.  Evaluation of the efficacy of a new modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine (Fostera PRRS) against heterologous PRRSV challenge. , 2014, Veterinary microbiology.

[4]  S. Youn,et al.  Comparative virulence of reproductive diseases caused by type 1 (European-like) and type 2 (North American-like) porcine reproductive and respiratory syndrome virus in experimentally infected pregnant gilts. , 2014, Journal of comparative pathology.

[5]  M. Kikkert,et al.  Arterivirus molecular biology and pathogenesis. , 2013, The Journal of general virology.

[6]  C. Chae,et al.  Comparison of the virulence of European and North American genotypes of porcine reproductive and respiratory syndrome virus in experimentally infected pigs. , 2013, Veterinary journal.

[7]  S. Revilla-Fernández,et al.  Effects on boar semen quality after infection with porcine reproductive and respiratory syndrome virus: a case report , 2013, Acta Veterinaria Scandinavica.

[8]  C. Chae,et al.  Pathogenesis of Korean type 1 (European genotype) porcine reproductive and respiratory syndrome virus in experimentally infected pigs. , 2012, Journal of comparative pathology.

[9]  J. Segalés,et al.  Comparative pathogenicity of type 1 and type 2 isolates of porcine reproductive and respiratory syndrome virus (PRRSV) in a young pig infection model. , 2011, Veterinary microbiology.

[10]  J. Shin,et al.  Effect of the Modified Live Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Vaccine on European and North American PRRSV Shedding in Semen from Infected Boars , 2011, Clinical and Vaccine Immunology.

[11]  H. Moon,et al.  Prevalence and phylogenetic analysis of the isolated type I porcine reproductive and respiratory syndrome virus from 2007 to 2008 in Korea , 2010, Virus Genes.

[12]  C. Prieto,et al.  Influence of time on the genetic heterogeneity of Spanish porcine reproductive and respiratory syndrome virus isolates. , 2009, Veterinary journal.

[13]  Changhee Lee,et al.  Complete genomic characterization of a European type 1 porcine reproductive and respiratory syndrome virus isolate in Korea , 2009, Archives of Virology.

[14]  G. Balka,et al.  Genetic diversity of porcine reproductive and respiratory syndrome virus strains circulating in Hungarian swine herds. , 2008, Veterinary microbiology.

[15]  M. Engle,et al.  Evaluation of the Sensitivity of Reverse-Transcription Polymerase Chain Reaction to Detect Porcine Reproductive and Respiratory Syndrome Virus on Individual and Pooled Samples from Boars , 2007, Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc.

[16]  B. Rossow,et al.  Sampling of adult boars during early infection with porcine reproductive and respiratory syndrome virus for testing by polymerase chain reaction using a new blood collection technique (blood-swab method) , 2006 .

[17]  S. Dee,et al.  Detection of porcine reproductive and respiratory syndrome virus in semen and serum of boars during the first six days after inoculation , 2006 .

[18]  I. Díaz,et al.  Use of ELISPOT and ELISA to evaluate IFN-γ, IL-10 and IL-4 responses in conventional pigs , 2005 .

[19]  Y. Lien,et al.  Real-time PCR for quantitation of porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 in naturally-infected and challenged pigs. , 2005, Journal of virological methods.

[20]  C. Prieto,et al.  Porcine reproductive and respiratory syndrome virus infection in the boar: a review. , 2005, Theriogenology.

[21]  I. Díaz,et al.  Use of ELISPOT and ELISA to evaluate IFN-gamma, IL-10 and IL-4 responses in conventional pigs. , 2005, Veterinary immunology and immunopathology.

[22]  M. Torremorell,et al.  Detection of U.S., Lelystad, and European-Like Porcine Reproductive and Respiratory Syndrome Viruses and Relative Quantitation in Boar Semen and Serum Samples by Real-Time PCR , 2004, Journal of Clinical Microbiology.

[23]  P. V. van Rijn,et al.  Detection of economically important viruses in boar semen by quantitative RealTime PCR™ technology , 2004, Journal of Virological Methods.

[24]  P. Halbur,et al.  The Level of Virus-Specific T-Cell and Macrophage Recruitment in Porcine Reproductive and Respiratory Syndrome Virus Infection in Pigs Is Independent of Virus Load , 2004, Journal of Virology.

[25]  F. Osorio,et al.  Gradual development of the interferon-gamma response of swine to porcine reproductive and respiratory syndrome virus infection or vaccination. , 2003, Virology.

[26]  Lawrence,et al.  Artificial insemination of gilts with porcine reproductive and respiratory syndrome ( PRRS ) virus-contaminateCi semen , 2003 .

[27]  J. Christopher-Hennings,et al.  Detection and Duration of Porcine Reproductive and Respiratory Syndrome Virus in Semen, Serum, Peripheral Blood Mononuclear Cells, and Tissues from Yorkshire, Hampshire, and Landrace Boars , 2001, Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc.

[28]  F. Osorio,et al.  North American and European porcine reproductive and respiratory syndrome viruses differ in non-structural protein coding regions. , 1999, The Journal of general virology.

[29]  M. Murtaugh,et al.  Porcine Reproductive and Respiratory Syndrome Virus Comparison: Divergent Evolution on Two Continents , 1999, Journal of Virology.

[30]  A. Bøtner,et al.  Sensitive detection and typing of porcine reproductive and respiratory syndrome virus by RT-PCR amplification of whole viral genes , 1998, Veterinary Microbiology.

[31]  C. Prieto,et al.  Insemination of susceptible and preimmunized gilts with boar semen containing porcine reproductive and respiratory syndrome virus. , 1997, Theriogenology.

[32]  J. Christopher-Hennings,et al.  Effects of a modified-live virus vaccine against porcine reproductive and respiratory syndrome in boars. , 1997, American journal of veterinary research.

[33]  C. Gradil,et al.  Porcine reproductive and respiratory syndrome virus: seminal transmission , 1996, Veterinary Record.

[34]  P. Halbur,et al.  Comparison of the Antigen Distribution of Two US Porcine Reproductive and Respiratory Syndrome Virus Isolates with that of the Lelystad Virus , 1996 .

[35]  J. Zimmerman,et al.  Persistence of Porcine Reproductive and Respiratory Syndrome Virus in Serum and Semen of Adult Boars , 1995, Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc.

[36]  J. Zimmerman,et al.  Detection of porcine reproductive and respiratory syndrome virus in boar semen by PCR , 1995, Journal of clinical microbiology.

[37]  F. Kibenge,et al.  Comparison of dot blot hybridization, polymerase chain reaction, and virus isolation for detection of bovine herpesvirus-1 (BHV-1) in artificially infected bovine semen. , 1995, Canadian journal of veterinary research = Revue canadienne de recherche veterinaire.

[38]  J. Christopher-Hennings,et al.  Evidence for the transmission of porcine reproductive and respiratory syndrome (PRRS) virus in boar semen , 1993 .

[39]  M. Schwyzer,et al.  A Comparison of Three Techniques for Detecting Bovine Herpesvirus Type 1 (BHV‐1) in Naturally and Experimentally Contaminated Bovine Semen , 1988 .