194 Performance and febrile response of nursery pigs to a porcine reproductive and respiratory syndrome virus challenge

Abstract Porcine reproductive and respiratory syndrome (PRRS) virus is an economically significant pathogen that antagonizes production in all stages of the swine industry. In nursery pigs, it increases the risk of mortality and reduces growth performance parameters. Thus, the objective of this study was to further understand how PRRS virus infection and its associated viremia and serology levels related to febrile response and performance in nursery pigs. Over two replicates, 37 three-week post-weaned PRRS naïve gilts (11.2 ± 2.56 kg BW) were randomly assigned to one of two treatments: Control (CON, n = 16) or PRRS virus-inoculated (PRRS+, n = 21). All pigs were housed individually in a BSL2 facility for the 21 d test period. PRRS serology, BW, ADG, ADFI, and G:F were determined at 0, 7, 14 and 21 days post inoculation (dpi). Core body temperatures were collected daily using a biosensor microchip. Data was analyzed using mixed procedure of SAS with dpi as a repeated effect and CON or PRRS+ as a treatment effect. Treatment, dpi and their interactions were assessed. As expected, viremia and antibody titers in PRRS+ pigs were significantly different compared to CON pigs, which remained negative (P < 0.001). The lowest PRRS Ct was observed at dpi 7, while antibody titers were highest between dpi 14 to 21 (P < 0.001). Compared with the CON, PRRS+ reduced BW gains by 17, 33 and 42% at dpi 7, 14 and 21 respectively (P < 0.001). The PRRS challenge also reduced ADFI by 30, 67 and 68% at dpi 7, 14 and 21 respectively, compared to CON (P < 0.001). The febrile response in the PRRS+ pigs peaked between dpi 7 and 14 then returned to CON baseline level by dpi 21 (P < 0.001). Overall, PRRS virus challenge induced a sustained febrile response that contributes to the attenuated performance of nursery pigs.

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PSVI-15 Effects of Vitamin B12, Sodium Salicylate, and electrolyte supplementation on alleviating Porcine Reproductive and Respiratory Syndrome symptoms in nursery pigs

Journal of Animal Science ◽

10.1093/jas/skz122.368 ◽

2019 ◽

Vol 97 (Supplement_2) ◽

pp. 209-209

Author(s):

Blaire Todd ◽

Carson De Mille ◽

Samuel Gerrard ◽

Emma T Helm ◽

Locke A Karriker ◽

...

Keyword(s):

Vitamin B12 ◽

Sodium Salicylate ◽

Post Inoculation ◽

Body Temperatures ◽

Nursery Pigs ◽

Prrs Virus ◽

Body Weights ◽

The Face ◽

Antibody Titers ◽

Pig Performance

Abstract Vitamin B12, sodium salicylate, and electrolyte treatments are commonly used to modulate pathogen induced fevers and aid in appetite stimulation. Therefore, the objective of this study was to determine the extent to which a B12 and sodium salicylate or an isotonic electrolyte treatment could improve growth performance and feed intake, and reduce the febrile response in porcine reproductive and respiratory syndrome (PRRS) virus inoculated pigs. A total of 32 PRRS-naïve gilts (7.7 ±1.5 kg BW; PIC Camborough x PIC 337) were selected and randomly assigned to individual pens across four treatments (n = 8/trt): 1) Control, PRRS-naïve, 2) PRRS virus infected, 3) As #2 plus B12 and sodium salicylate supplementation, and 4) As #2 plus isotonic electrolyte supplementation. On days post inoculation (dpi) 0, pigs were inoculated with PRRS virus. B12 was administered weekly, sodium salicylate and the electrolyte solution were given orally daily in the water or fed daily from dpi 4-18. Body temperatures and feed intakes were measured daily, and body weights, G:F, and PRRS serology assessed weekly for 21 dpi. Over the 21 day test period, irrespective of treatment, PRRS virus infection resulted in a significant increase in PRRS viremia and antibody titers compared to the control (P < 0.05). Compared to treatment #2, B12 + sodium salicylate and electrolyte treatments did not have differing body temperatures, ADG, ADFI or G:F. However, PRRS infection resulted in a significant increase in average body temperature compared to the control (39.8 vs. 39.3 oC, respectively, P = 0.021). Compared to the control, PRRS infection reduced overall ADG by 83% (0.54 verses 0.09 g/d, P < 0.001), end BW by 9 kg (P < 0.001) and ADFI by 11% (P < 0.001) compared to the control. Although treatment did not improve pig performance in the face of PRRS, mortality rates were significantly (P < 0.050) reduced compared to the PRRS only treatment.

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Increasing the ratio of SID lysine to metabolizable energy improves pig performance during a viral challenge

Journal of Animal Science ◽

10.1093/jas/skaa082 ◽

2020 ◽

Vol 98 (4) ◽

Author(s):

Jessica E Jasper ◽

Omarh F Mendoza ◽

Caleb M Shull ◽

Wesley P Schweer ◽

Kent J Schwartz ◽

...

Keyword(s):

Control Diet ◽

Average Daily Gain ◽

National Research Council ◽

Metabolizable Energy ◽

Respiratory Syndrome Virus ◽

Post Inoculation ◽

Virus Challenge ◽

Prrs Virus ◽

Energy Needs ◽

Pig Performance

Abstract Porcine reproductive and respiratory syndrome virus (PRRSV) compromises pig performance. However, increasing standardized ileal digestible Lys per Mcal metabolizable energy (SID Lys:ME) above requirement has been shown to mitigate reduced performance seen during a porcine reproductive and respiratory syndrome (PRRS) virus challenge. The objective of this study was to evaluate the effects of increasing the dietary SID Lys:ME from 100% National Research Council (NRC) requirement to 120% of the requirement in vaccinated (vac+; modified live vaccine Ingelvac PRRS) and non-vaccinated (vac−; no PRRS vaccine) grower pigs subjected to a PRRSV challenge. In addition, the dietary formulation approach to achieve the 120% ratio by increasing Lys relative to energy (HL) or diluting energy in relation to Lys (LE) was evaluated. This allowed us to test the hypothesis that pigs undergoing a health challenge would have the ability to eat to their energy needs. Within vaccine status, 195 mixed-sex pigs, vac+ (35.2 ± 0.60 kg body weight [BW]) and vac− (35.2 ± 0.65 kg BW) were randomly allotted to one of three dietary treatments (2.67, 3.23, or 3.22 g SID Lys:ME) for a 42-d PRRS virus challenge study representing 100%, 120%, and 120% of NRC requirement, respectively. Pigs were randomly allotted across two barns, each containing 24 pens with 7 to 10 pigs per pen (8 pens per diet per vaccine status). On day post-inoculation 0, both barns were inoculated with PRRSV and started on experimental diets. Within vaccine status, weekly and overall challenge period pig performance were assessed. In both vac+ (P < 0.05) and vac− (P < 0.05) pigs, the HL and LE diets increased end BW and overall average daily gain (ADG) ADG compared with pigs fed the control diet (P < 0.05). Overall, average daily feed intake (ADFI) during the challenge period was greater (P < 0.05) for pigs fed the LE diet compared with pigs fed control and HL treatments, regardless of vaccine status (20% and 17% higher ADFI than the control in vac+ and vac− pigs, respectively). The HL vac+ pigs had the greatest gain to feed (G:F) compared with the control and LE pigs (0.438 vs. 0.394 and 0.391 kg/kg, respectively; P < 0.01). Feed efficiency was not impacted (P > 0.10) by treatment in the vac− pigs. In summary, PRRSV-challenged grower pigs consumed feed to meet their energy needs as indicated by the increase in ADFI when energy was diluted in the (LE) diet, compared with control pigs. In both PRRS vac+ and vac− pigs subsequently challenged with PRRSV, regardless of formulation approach, fed 120% SID Lys:ME diets resulted in enhanced overall growth performance.

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Structural comparison of CD163 SRCR5 from different species sheds some light on its involvement in porcine reproductive and respiratory syndrome virus-2 infection in vitro

Veterinary Research ◽

10.1186/s13567-021-00969-z ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Hongfang Ma ◽

Rui Li ◽

Longguang Jiang ◽

Songlin Qiao ◽

Xin-xin Chen ◽

...

Keyword(s):

Scavenger Receptor ◽

Host Cells ◽

Respiratory Syndrome Virus ◽

Swine Industry ◽

Prrs Virus ◽

Rich Domain ◽

Serious Disease ◽

The One ◽

And Control

AbstractPorcine reproductive and respiratory syndrome (PRRS) is a serious disease burdening global swine industry. Infection by its etiological agent, PRRS virus (PRRSV), shows a highly restricted tropism of host cells and has been demonstrated to be mediated by an essential scavenger receptor (SR) CD163. CD163 fifth SR cysteine-rich domain (SRCR5) is further proven to play a crucial role during viral infection. Despite intense research, the involvement of CD163 SRCR5 in PRRSV infection remains to be elucidated. In the current study, we prepared recombinant monkey CD163 (moCD163) SRCR5 and human CD163-like homolog (hCD163L1) SRCR8, and determined their crystal structures. After comparison with the previously reported crystal structure of porcine CD163 (pCD163) SRCR5, these structures showed almost identical structural folds but significantly different surface electrostatic potentials. Based on these differences, we carried out mutational research to identify that the charged residue at position 534 in association with the one at position 561 were important for PRRSV-2 infection in vitro. Altogether the current work sheds some light on CD163-mediated PRRSV-2 infection and deepens our understanding of the viral pathogenesis, which will provide clues for prevention and control of PRRS.

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The Function of the PRRSV–Host Interactions and Their Effects on Viral Replication and Propagation in Antiviral Strategies

Vaccines ◽

10.3390/vaccines9040364 ◽

2021 ◽

Vol 9 (4) ◽

pp. 364

Author(s):

Jun Ma ◽

Lulu Ma ◽

Meiting Yang ◽

Wei Wu ◽

Wenhai Feng ◽

...

Keyword(s):

Immune Response ◽

Molecular Mechanisms ◽

Immune Escape ◽

Rna Virus ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Swine Industry ◽

Live Virus ◽

Virus Challenge ◽

Host Interactions

Porcine reproductive and respiratory syndrome virus (PRRSV) affects the global swine industry and causes disastrous economic losses each year. The genome of PRRSV is an enveloped single-stranded positive-sense RNA of approximately 15 kb. The PRRSV replicates primarily in alveolar macrophages of pig lungs and lymphatic organs and causes reproductive problems in sows and respiratory symptoms in piglets. To date, studies on how PRRSV survives in the host, the host immune response against viral infections, and pathogenesis, have been reported. PRRSV vaccines have been developed, including inactive virus, modified live virus, attenuated live vaccine, DNA vaccine, and immune adjuvant vaccines. However, there are certain problems with the durability and effectiveness of the licensed vaccines. Moreover, the high variability and fast-evolving populations of this RNA virus challenge the design of PRRSV vaccines, and thus effective vaccines against PRRSV have not been developed successfully. As is well known, viruses interact with the host to escape the host’s immune response and then replicate and propagate in the host, which is the key to virus survival. Here, we review the complex network and the mechanism of PRRSV–host interactions in the processes of virus infection. It is critical to develop novel antiviral strategies against PRRSV by studying these host–virus interactions and structures to better understand the molecular mechanisms of PRRSV immune escape.

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Multiplex RT-PCR assay to differentiate genotypes of porcine reproductive and respiratory syndrome virus in swine

The Journal of Agriculture and Development ◽

10.52997/jad.2.06.2019 ◽

2019 ◽

Vol 18 (06) ◽

pp. 8-13

Author(s):

Phat X. Dinh

Keyword(s):

Real Time ◽

Clinical Samples ◽

Respiratory Syndrome Virus ◽

Rt Pcr ◽

Pcr Assay ◽

Swine Industry ◽

Diagnostic Challenge ◽

Nsp2 Gene ◽

Prrs Virus ◽

Pcr Products

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important diseases to swine industry worldwide. Due to the heterogeneity of field isolates, accurate detection of the PRRS virus is a diagnostic challenge. Recently, co-infection with NA-PRRSV, EU-PRRSV and HP-PRRSV isolates continuously increases in many countries, resulting in a significant impact on PRRSV diagnostics and disease control on farms. To facilitate rapid diagnosis and reliable discrimination of NA-PRRSV, EU-PRRSV and HP-PRRSV, a multiplex RT-PCR assay was established with three pairs of primers targeting highly conservative regions of nsp2 gene with predicted multiplex RT-PCR products of 364 bp, 161 bp and 259 bp, respectively. The primer pairs were optimized to be highly specific for PRRSV genotypes and were able to detect the target gene at the limit of 102 copies/μL for each gene. Clinical samples were used to evaluate this multiplex RT-PCR in parallel with a commercial real-time RT-PCR kit. Results showed over 95.2% (20/21 samples) agreement between the mRT-PCR and the real-time RT-PCR kit. Hence, it indicated that this multiplex RT-PCR could be useful for rapid and deferential diagnosis of NA-PRRSV, EU-PRRSV and HP-PRRSV in swine farms.

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Blood antioxidant enzymes (SOD, GPX), biochemical and haematological parameters in pigs naturally infected with porcine reproductive and respiratory syndrome virus

Polish Journal of Veterinary Sciences ◽

10.2478/pjvs-2013-0049 ◽

2013 ◽

Vol 16 (2) ◽

pp. 369-376 ◽

Cited By ~ 8

Author(s):

M. Štukelj ◽

I. Toplak ◽

A. Nemec Svete

Keyword(s):

Oxidative Stress ◽

Antioxidant Enzymes ◽

Vena Cava ◽

Blood Parameters ◽

Haematological Parameters ◽

Respiratory Syndrome Virus ◽

Swine Industry ◽

Prrs Virus ◽

First Time ◽

Gpx Activity

Abstract Porcine reproductive and respiratory syndrome (PRRS) has become one of the most economically important diseases for the swine industry worldwide. The objective of the study was to determine selected blood antioxidant enzymes (glutathione peroxidase (GPX), superoxide dismutase (SOD)), biochemical and haematological parameters in PRRS positive and negative pigs of three different categories, mainly to test oxidative stress hypothesis in pigs naturally infected with PRRS virus. Ninety PRRS positive and 90 PRRS negative pigs were included in the study. The presence of PRRS was confirmed by serological detection of antibodies against PRRS virus (PRRSV) and detection of PRRS viral RNA by RT-PCR. Pigs were further divided into three groups of 30: piglets just before weaning (weaners), fatteners and finishers. Blood samples for determining selected blood parameters were collected from the vena cava cranialis. Significantly (P < 0.05) higher activities of SOD in weaners and fatteners and of GPX in weaners were determined in PRRS positive pigs than in corresponding groups of PRRS negative pigs. In contrast, significantly (P < 0.05) lower GPX activity was observed in finishers of PRRS positive pigs than in the corresponding group of PRRS negative pigs. Concentrations of serum total protein in PRRS positive weaners and fatteners were significantly (P < 0.05) higher than those found in PRRS negative pigs. Leukopenia was observed in all three groups of PRRS positive pigs. It has been demonstrated, for the first time, that oxidative stress might be increased in PRRSV naturally infected pigs, especially in weaners.

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The effect of porcine reproductive and respiratory syndrome virus and porcine epidemic diarrhea virus challenge on growing pigs I: Growth performance and digestibility1

Journal of Animal Science ◽

10.2527/jas.2015-9834 ◽

2016 ◽

Vol 94 (2) ◽

pp. 514-522 ◽

Cited By ~ 17

Author(s):

W. P. Schweer ◽

K Schwartz ◽

E. R. Burrough ◽

K. J. Yoon ◽

J. C. Sparks ◽

...

Keyword(s):

Growth Performance ◽

Growing Pigs ◽

Respiratory Syndrome Virus ◽

Free Access ◽

Standard Diet ◽

Virus Challenge ◽

Diarrhea Virus ◽

Prrs Virus ◽

Porcine Epidemic Diarrhea ◽

The Impact

Abstract Porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED) are two diseases costly to the U.S. swine industry. The objective of this study was to determine the impact of PRRS virus and PED virus, alone or in combination, on growth performance, feed efficiency, and digestibility in grower pigs. Forty-two gilts (16 ± 0.98 kg BW) naïve for PRRS and PED were selected and allocated to 1 of 4 treatments. Treatments included 1) a control, 2) PRRS virus infected, 3) PED virus infected, and 4) PRRS+PED coinfection (PRP). Pigs in treatments 2 and 4 were inoculated with a live field strain of PRRS virus via intramuscular and intranasal routes at 0 d after inoculation (dpi). Treatments 3 and 4 were orally inoculated with a cloned PED virus at 15 dpi. Infection with PRRS virus was confirmed by quantitative PCR and seroconversion. Infection with PED virus was confirmed with PCR. Control pigs remained PRRS and PED virus negative throughout the study. All pigs were offered, ad libitum, a standard diet with free access to water. During the test period, PRRS reduced ADG and ADFI by 30 and 26%, respectively (P < 0.05), compared with control pigs, whereas PRP decreased ADG, ADFI, and G:F by 45, 30, and 23%, respectively (P < 0.05). Additional reductions in ADG and G:F were detected in PRP pigs compared with singular PED or PRRS treatments (33 and 16%, respectively). The impact of PED, alone or in combination, on performance (15–21 dpi) reduced ADG (0.66 vs. 0.35 vs. 0.20 kg/d; P < 0.01), ADFI (1.22 vs. 0.88 vs. 0.67 kg/d; P = 0.003), and G:F (0.54 vs. 0.39 vs. 0.31; P = 0.001) compared with control pigs. Compared with control pigs, PRRS infection did not reduce apparent total tract digestibility (ATTD) of nutrients and energy. However, PED infection, alone or in combination, decreased ATTD of DM and energy by 8 and 12%, respectively (P < 0.05). Compared with control pigs, PRP reduced N and OM ATTD by 13 and 3%, respectively (P < 0.05). No significant differences in apparent ileal digestibility (AID) were detected between virus challenges. However, Lys AID tended to be reduced in both PED treatments compared with the control (10 and 12%; P = 0.095). Altogether, PRRS reduced growth but did not alter digestibility. Pigs challenged with PED and, to a greater extent, the coinfection of PED and PRRS viruses had reduced ADG, ADFI, G:F, and ATTD of nutrients and energy.

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Porcine Reproductive and Respiratory Syndrome Virus Utilizes Viral Apoptotic Mimicry as an Alternative Pathway To Infect Host Cells

Journal of Virology ◽

10.1128/jvi.00709-20 ◽

2020 ◽

Vol 94 (17) ◽

Cited By ~ 1

Author(s):

Xin Wei ◽

Rui Li ◽

Songlin Qiao ◽

Xin-xin Chen ◽

Guangxu Xing ◽

...

Keyword(s):

Viral Infection ◽

Rho Gtpases ◽

Alternative Pathway ◽

Low Ph ◽

Host Cells ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Swine Industry ◽

Prrs Virus ◽

Ph Dependent

ABSTRACT Porcine reproductive and respiratory syndrome (PRRS), caused by PRRS virus (PRRSV), has led to enormous economic losses in global swine industry. Infection by PRRSV is previously shown to be via low pH-dependent clathrin-mediated endocytosis, and CD163 functions as an essential receptor during viral infection. Despite much research focusing on it, PRRSV infection remains to be fully elucidated. In this study, we demonstrated that PRRSV externalized phosphatidylserine (PS) on the envelope as viral apoptotic mimicry and infected host cells through T-cell immunoglobulin and mucin domain (TIM)-induced and CD163-involved macropinocytosis as an alternative pathway. In detail, we identified that PS receptor TIM-1/4 recognized and interacted with PRRSV as viral apoptotic mimicry and subsequently induced macropinocytosis by the downstream Rho GTPases Rac1, cell division control protein 42 (Cdc42), and p21-activated kinase 1 (Pak1). Altogether, these results expand our knowledge of PRRSV infection, which will support implications for the prevention and control of PRRS. IMPORTANCE PRRS has caused huge economic losses to pig farming worldwide. Its causative agent, PRRSV, infects host cells through low pH-dependent clathrin-mediated endocytosis and CD163 is indispensable during the process. Whether there exist alternative infection pathways for PRRSV arouses our interest. Here, we found that PRRSV exposed PS on its envelope and disguised as apoptotic debris. The PS receptor TIM-1/4 recognized PRRSV and induced the downstream signaling pathway to mediate viral infection via CD163-dependent macropinocytosis. The current work deepens our understanding of PRRSV infection and provides clues for the development of drugs and vaccines against the virus.

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Aptamer-Based QCM-Sensor for Rapid Detection of PRRS Virus

Proceedings ◽

10.3390/proceedings2131038 ◽

2018 ◽

Vol 2 (13) ◽

pp. 1038

Author(s):

Chakpetch Kuitio ◽

Kiattawee Choowongkomon ◽

Peter A. Lieberzeit

Keyword(s):

Classical Swine Fever Virus ◽

Rapid Detection ◽

Quartz Crystal ◽

Pseudorabies Virus ◽

Rna Virus ◽

Classical Swine Fever ◽

Respiratory Syndrome Virus ◽

Swine Industry ◽

Virus Particles ◽

Prrs Virus

Porcine reproductive and respiratory syndrome (PRRS) is caused by an RNA virus and has substantial economic impact on swine industry. Screening pigs for infection is the best way to prevent spreading the disease. For that purpose, we developed biosensors based on aptamers, i.e., short ss-DNA that can bind to porcine reproductive and respiratory syndrome virus (PRRSV). The present study, demonstrates selectivity and sensitivity of PRRSV aptamer (7R) by the means of quartz crystal microbalance (QCM) measurements. The respective results show that 7R aptamer indeed binds to samples containing around 1010 PRRSV virus particles, but not to Pseudorabies virus (PRV) and Classical swine fever virus (CSFV).

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Impacts of Quarterly Sow Mass Vaccination with a Porcine Reproductive and Respiratory Syndrome Virus Type 1 (PRRSV-1) Modified Live Vaccine in Two Herds

Vaccines ◽

10.3390/vaccines9101057 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1057

Author(s):

Kasper Pedersen ◽

Charlotte Sonne Kristensen ◽

Lise Kirstine Kvisgaard ◽

Lars Erik Larsen

Keyword(s):

Negative Impact ◽

Mass Vaccination ◽

Respiratory Syndrome Virus ◽

Nursery Pigs ◽

Prrs Virus ◽

Before And After ◽

Strain Virus ◽

Modified Live Vaccine ◽

Paired Design ◽

The Impact

In recent years, there has been a considerable increase in the use of Modified Live PRRSV Vaccines (MLV) for mass vaccination in Denmark. The potential risks and negative impact of this strategy have been sparsely studied. The aim of this study was to investigate the impact of quarterly sow mass vaccination in two Danish sow herds. The study was performed as an observational prospective cohort of 120 sows in each of two commercial breeding herds in a paired design. Blood samples were taken from sows and oral fluid samples from nursery pigs (four to ten weeks old) before and after vaccination. The presence of PRRSV-1 RNA was measured by real time quantitative reverse transcription-polymerase chain reaction (RT-qPCR), and the level of PRRSV-1 specific antibodies was measured by two different serological assays. PRRS virus was not detected in the sow herds two days before and two weeks after vaccination, but the vaccine strain virus was detected in the nursery pigs. The prevalence of sows without antibodies towards PRRSV-1 went from 6–15% before vaccination to 1–4% after vaccination depending on the serological assay used, despite the fact that they had previously been repeatedly vaccinated. Four sows tested negative for antibodies in both assays after vaccination.

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