Genetic Parameters and Effect of WUR Genotype on Piglet Response to Co-Infection with PRRS and PCV2b, with or without Vaccination for PRRS

Commercial crossbred nursery piglets were either vaccinated or not using a modified live porcine reproductive and respiratory syndrome (PRRS) virus vaccine and all pigs were co-infected with PRRS virus (PRRSV) and porcine circovirus type 2b (PCV2b) 28 days later. Genetic correlations indicate that traits associated with primary exposure to PRRSV infection (PRRS viral load (VL) of vaccinated pigs prior to co-infection and PRRS VL of non-vaccinated pigs post co-infection) are genetically the same trait. The WUR single nucleotide polymorphism on chromosome 4, previously associated with reduced PRRS VL under PRRSV-only infection, was associated with significantly reduced PRRS VL following vaccination and co-infection (for non-vaccinated pigs), but also with reduced PCV2b VL of vaccinated pigs. These results indicate a significant effect of WUR genotype on PRRS VL upon primary PRRS exposure, whether in a PRRSV-only or PRRS and PCV2b co-infected population, but also with PCV2b VL of vaccinated pigs under PRRS and PCV2b co- infection

Effect of WUR Genotype and PRRS Vaccination on Pigs Co-Infected with PRRS and PCV2b

Average daily gain (ADG) and viral load (VL) were evaluated for pigs co-infected with porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) and porcine circovirus type 2b (PCV2b). Pigs were pre-selected for WUR genotype (a marker on chromosome 4 associated with weight gain and VL under PRRSV-challenge), half were vaccinated for PRRS, and half were not. Results indicate that vaccination for PRRS resulted in slower growth prior to co-infection and that the AB WUR genotype was associated with faster growth prior to co-infection, lower PRRS VL, and lower PCV2b VL in vaccinated pigs

Antibody responses following vaccination versus infection in a porcine circovirus-type 2 (PCV2) disease model show distinct differences in virus neutralization and epitope recognition

Porcine circovirus associated disease (PCVAD) encompasses a group of syndromes linked to infection with porcine circovirus type 2 (PCV2). Based on the hypothesis that the immune responses to vaccination versus infection are quantitatively and qualitatively different, the objective of this study was to evaluate immunity, virus replication and disease protection in pigs vaccinated with PCV2 capsid protein (CP) and during infection. The disease model included dual infection with PCV2 and porcine reproductive and respiratory syndrome virus (PRRSV), a virus known to enhance disease progression and severity. The principal effect of PRRSV infection was to increase peak PCV2 viremia by almost 40-fold; however, PCV2 failed to show a reciprocal effect on PRRSV. In vaccinated pigs, there was no evidence of disease or PCV2 replication following dual virus challenge. Immunity following vaccination favored PCV2 neutralizing activity; whereas, PCV2 infection and disease produced high levels of non-neutralizing antibody, primarily directed against a polypeptide in the C-terminal region of CP. These results support the notion that the magnitude of the total antibody response cannot be used as a measure of protective immunity. Furthermore, protection versus disease lies in the immunodominance of specific epitopes. Epitope specificity should be taken into consideration when designing PCV2 vaccines

Comparison of host immune responses to homologous and heterologous type II porcine reproductive and respiratory syndrome virus (PRRSV) challenge in vaccinated and unvaccinated pigs

Porcine reproductive and respiratory syndrome (PRRS) is a high-consequence animal disease with current vaccines providing limited protection from infection due to the high degree of genetic variation of field PRRS virus. Therefore, understanding host immune responses elicited by different PRRSV strains will facilitate the development of more effective vaccines. Using IngelVac modified live PRRSV vaccine (MLV), its parental strain VR-2332, and the heterologous KS-06-72109 strain (a Kansas isolate of PRRSV), we compared immune responses induced by vaccination and/or PRRSV infection. Our results showed that MLV can provide complete protection from homologous virus (VR-2332) and partial protection from heterologous (KS-06) challenge. The protection was associated with the levels of PRRSV neutralizing antibodies at the time of challenge, with vaccinated pigs having higher titers to VR-2332 compared to KS-06 strain. Challenge strain did not alter the cytokine expression profiles in the serum of vaccinated pigs or subpopulations of T cells. However, higher frequencies of IFN-γ-secreting PBMCs were generated from pigs challenged with heterologous PRRSV in a recall response when PBMCs were re-stimulated with PRRSV. Thus, this study indicates that serum neutralizing antibody titers are associated with PRRSV vaccination-induced protection against homologous and heterologous challenge

Probing genetic control of swine responses to PRRSV infection: current progress of the PRRS host genetics consortium

<p>Abstract</p> <p>Background</p> <p>Understanding the role of host genetics in resistance to porcine reproductive and respiratory syndrome virus (PRRSV) infection, and the effects of PRRS on pig health and related growth, are goals of the PRRS Host Genetics Consortium (PHGC).</p> <p>Methods</p> <p>The project uses a nursery pig model to assess pig resistance/susceptibility to primary PRRSV infection. To date, 6 groups of 200 crossbred pigs from high health farms were donated by commercial sources. After acclimation, the pigs were infected with PRRSV in a biosecure facility and followed for 42 days post infection (dpi). Blood samples were collected at 0, 4, 7, 10, 14, 21, 28, 35 and 42 dpi for serum and whole blood RNA gene expression analyses; weekly weights were recorded for growth traits. All data have been entered into the PHGC relational database. Genomic DNAs from all PHGC1-6 pigs were prepared and genotyped with the Porcine SNP60 SNPchip.</p> <p>Results</p> <p>Results have affirmed that all challenged pigs become PRRSV infected with peak viremia being observed between 4-21 dpi. Multivariate statistical analyses of viral load and weight data have identified PHGC pigs in different virus/weight categories. Sera are now being compared for factors involved in recovery from infection, including speed of response and levels of immune cytokines. Genome-wide association studies (GWAS) are underway to identify genes and chromosomal locations that identify PRRS resistant/susceptible pigs and pigs able to maintain growth while infected with PRRSV.</p> <p>Conclusions</p> <p>Overall, the PHGC project will enable researchers to discover and verify important genotypes and phenotypes that predict resistance/susceptibility to PRRSV infection. The availability of PHGC samples provides a unique opportunity to continue to develop deeper phenotypes on every PRRSV infected pig.</p

Evaluation and Treatment of Creosote in Soil

For over a century, creosote has been successfully used to preserve wood products by retarding the growth of microorganisms and insects. Its effectiveness although imposes a health problem because several of its components are potentially harmful to humans. In heavily contaminated areas, creosote can leach through the soil and contaminate ground water supplies before it can be either volatilized, immobilized or degraded. Furthermore, heavily creosote contaminated soils are generally very dark in appearance and void of vegetation. In this investigation, the fate of creosote in soil was evaluated with respect to the soil microorganism population and the growth of rye grass. Bacteriological analyses were performed to relate the microbial counts to the degradation of creosote in the soil. In addition, rye grass was grown in contaminated soil to determine how it was effected by the creosote. Soil amendments were also used to determine whether additional nutrients and humus would increase the partial degradation of creosote and hence, decrease the length of time necessary to treat the contaminated soil

Effect of WUR Genotype and PRRS Vaccination on Pigs Co-Infected with PRRS and PCV2b

Average daily gain (ADG) and viral load (VL) were evaluated for pigs co-infected with porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) and porcine circovirus type 2b (PCV2b). Pigs were pre-selected for WUR genotype (a marker on chromosome 4 associated with weight gain and VL under PRRSV-challenge), half were vaccinated for PRRS, and half were not. Results indicate that vaccination for PRRS resulted in slower growth prior to co-infection and that the AB WUR genotype was associated with faster growth prior to co-infection, lower PRRS VL, and lower PCV2b VL in vaccinated pigs.</p

Genetic Parameters and Effect of WUR Genotype on Piglet Response to Co-Infection with PRRS and PCV2b, with or without Vaccination for PRRS

Commercial crossbred nursery piglets were either vaccinated or not using a modified live porcine reproductive and respiratory syndrome (PRRS) virus vaccine and all pigs were co-infected with PRRS virus (PRRSV) and porcine circovirus type 2b (PCV2b) 28 days later. Genetic correlations indicate that traits associated with primary exposure to PRRSV infection (PRRS viral load (VL) of vaccinated pigs prior to co-infection and PRRS VL of non-vaccinated pigs post co-infection) are genetically the same trait. The WUR single nucleotide polymorphism on chromosome 4, previously associated with reduced PRRS VL under PRRSV-only infection, was associated with significantly reduced PRRS VL following vaccination and co-infection (for non-vaccinated pigs), but also with reduced PCV2b VL of vaccinated pigs. These results indicate a significant effect of WUR genotype on PRRS VL upon primary PRRS exposure, whether in a PRRSV-only or PRRS and PCV2b co-infected population, but also with PCV2b VL of vaccinated pigs under PRRS and PCV2b co- infection.</p

Preliminary findings of a previously unrecognized porcine primary immunodeficiency disorder

Weaned pigs from a line bred for increased feed efficiency were enrolled in a study of the role of host genes in the response to infection with Porcine Reproductive and Respiratory Syndrome Virus (PRRSV). However, 4 of the pigs were euthanized early in the study due to weight loss with poor body condition and illness; 2 pigs, before PRRSV infection, and the other 2, approximately 2 weeks after virus inoculation. The 2 inoculated pigs failed to produce PRRSV-specific antibodies. Gross findings included pneumonia, absence of a detectable thymus, and small secondary lymphoid tissues. Histologically, lymph nodes, spleen, tonsils, and Peyer’s patches were sparsely cellular with decreased to absent T and B lymphocytes

Intracellular Localization of the Severe Acute Respiratory Syndrome Coronavirus Nucleocapsid Protein: Absence of Nucleolar Accumulation during Infection and after Expression as a Recombinant Protein in Vero Cells

The nucleocapsid (N) protein of several members within the order Nidovirales localizes to the nucleolus during infection and after transfection of cells with N genes. However, confocal microscopy of N protein localization in Vero cells infected with the severe acute respiratory syndrome coronavirus (SARS-CoV) or transfected with the SARS-CoV N gene failed to show the presence of N in the nucleoplasm or nucleolus. Amino acids 369 to 389, which contain putative nuclear localization signal (NLS) and nucleolar localization signal motifs, failed to restore nuclear localization to an NLS-minus mutant Rev protein. These data indicate that nuclear localization is not a conserved property among all nidoviruses