Effects of North American Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)-Based Modified Live Vaccines on Preimmunized Sows Artificially Inseminated with European PRRSV-Spiked Semen

Abstract

The objective of the present study was to determine if the European porcine reproductive and respiratory syndrome virus (PRRSV) can be transmitted via spiked semen to preimmunized sows and induce reproductive failure. Sows were immunized with the North American PRRSV-based modified live vaccine (Ingelvac PRRS MLV; Boehringer Ingelheim Animal Health, St. Joseph, MO) and were artificially inseminated. The sows were randomly divided into three groups. The vaccinated (group 2) and nonvaccinated (group 3) sows developed a PRRSV viremia at 7 to 28 days postinsemination with the European PRRSV-spiked semen. The number of genomic copies of the European PRRSV in serum samples was not significantly different between vaccinated and nonvaccinated sows. All negative-control sows in group 1 farrowed at the expected date. The sows in groups 2 and 3 farrowed between 103 and 110 days after the first insemination. European PRRSV RNA was detected in the lungs of 8 out of 11 live-born piglets and 46 out of 54 stillborn fetuses. In addition, PRRSV RNA was detected using in situ hybridization in other tissues from vaccinated sows that had been inseminated with European PRRSV-spiked semen (group 2). The present study has demonstrated that vaccinating sows with the North American PRRSV-based modified live vaccine does not prevent reproductive failure after insemination with European PRRSV-spiked semen.

Risk Assessment of the Introduction of Porcine Reproductive and Respiratory Syndrome Virus via Boar Semen into Switzerland as an Example of a PRRSV-Free Country

“…Another substantial route is by means of PRRSV‐positive boar semen. This was reported from field cases and could be confirmed in different experimental studies (Swenson et al., ; Gradil et al., ; Prieto et al., ; Han et al., ). In a study focusing on the spread of PRRSV in the late 1990s, it was estimated that 20% of infections in sow herds originated from PRRSV‐positive semen (Le Potier et al., ).…”

Commercial porcine reproductive and respiratory syndrome virus (PRRSV)‐2 modified live virus vaccine against heterologous single and dual Korean PRRSV‐1 and PRRSV‐2 challenge

“…PRRSV‐1 (SNUVR090485, pan‐European subtype 1, GenBank no. ) was isolated from lung samples of an aborted fetus and a weaned pig in a 1000‐sow herd in southwestern Kyounggi Province 14 . PRRSV‐2 (SNUVR090851 strain, lineage 1, GenBank no. )…”

Broadening the Heterologous Cross-Neutralizing Antibody Inducing Ability of Porcine Reproductive and Respiratory Syndrome Virus by Breeding the GP4 or M genes

“…The extensive antigenic and genetic variations among field strains of PRRSV are largely responsible for the poor cross-protection of the current vaccines against heterologous strains [18]–[20]. The available modified live-attenuated vaccines (MLVs), which are all based on single PRRSV strains, can provide effective protection against homologous or genetically similar strains, but are not effective against the heterologous strains [21]–[23]. A biodegradable nanoparticle-entrapped vaccine was shown to induce cross-protective immunity against a heterologous PRRSV strain [24].…”