. 2022 May 13;204:105669.

 doi: 10.1016/j.prevetmed.2022.105669.Online ahead of print.

Comparison of virus detection, productivity, and economic performance between lots of growing pigs vaccinated with two doses or one dose of PRRS MLV vaccine, under field conditions

Cesar A A Moura 1, Reid Philips 2, Gustavo S Silva 1, Derald J Holtkamp 1, Daniel C L Linhares 3

Affiliations 

Affiliations

• 1Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
• 2Boehringer Ingelheim Animal Health USA Inc., Duluth, GA, USA.
• 3Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Ames, IA, USA. Electronic address: linhares@iastate.edu.

• PMID: 35594607
 
• DOI: 10.1016/j.prevetmed.2022.105669

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) causes a significant economic impact on swine production. It has been demonstrated that PRRS modified-live virus (MLV) vaccination of pigs, with one full dose, significantly reduces clinical consequences of wild-type PRRSV infection compared to non-vaccinates. However, there is limited information about the effect that two doses of PRRSV MLV vaccine have on the performance of growing pigs, compared to vaccination with a single dose. This study was conducted with the objectives to compare (a) the wild-type PRRSV detection in oral fluids over time, (b) key closeout productivity indicators, and (c) economic performance between lots of growing pigs vaccinated with two doses of Ingelvac PRRS® MLV vaccine and lots vaccinated with a single dose of the same vaccine. This randomized field trial included 15 lots of growing pigs from PRRSV positive-unstable sow farms and 66 lots from PRRSV positive-stable sow farms, according to the American association of swine veterinarians' terminology. All pig lots received the first vaccination either around processing or weaning age. Lots allocated in the two doses group received the second vaccination three to four weeks after the first vaccination. The pig lots were monitored for PRRSV detection over time. Six oral fluids samples were collected in three weeks intervals and were tested for wild-type PRRSV-2 RNA by RT-qPCR and open reading frame 5 (ORF)- 5 sequencing. Regression models were used to compare wild-type PRRSV detection dynamics on oral fluids samples and to compare key closeout performance indicators between one dose group and two doses group. Additionally, a benefit-cost ratio analysis compared economic performance between one dose group and two doses group. The proportion of wild-type PRRSV detection on oral fluids samples and the log counts of viral RNA per ml of oral fluids from the two doses group was lower than the one dose group on lots originated from PRRSV positive-stable sow farms, with a risk ratio of 1.24 and a rate ratio of 1.17, respectively. The two doses group had a significantly lower mortality rate than the one dose group, with a rate ratio of 1.21. The effect size increased on lots originated from PRRSV positive-unstable sow farms, and on lots with higher frequency and diversity of wild-type PRRSV detection during the growth phase. No differences in growth performance were detected between two doses group and one dose group. The second MLV vaccination dose had a benefit-cost ratio of 1.83. For lots originated from PRRSV positive-unstable farms, the benefit-cost ratio was 4.45, and for lots originated from PRRSV positive-stable farms, the benefit-cost ratio was 0.45. Under study conditions, vaccinating growing pig lots with two doses of PRRS MLV vaccine was a useful strategy to immunize growing pigs against PRRSV, lowering the wild-type PRRSV detection, lowering mortality rate, and increasing profitability, compared to lots of growing pigs that received a single dose of the same vaccine.

Keywords: Field epidemiology; Growing pigs; PRRSV; Two MLV doses; Vaccination.

Copyright © 2022 Elsevier B.V. All rights reserved.

Safety of PRRSV-2 MLV vaccines administrated via the intramuscular or intradermal route and evaluation of transmission upon needle-free and needle delivery

 Sci Rep.

2021 Nov 29;11(1):23107. doi: 10.1038/s41598-021-02444-3.

Safety of PRRSV-2 MLV vaccines administrated via the intramuscular or intradermal route and evaluation of PRRSV transmission upon needle-free and needle delivery

Adthakorn Madapong 1, Kepalee Saeng-Chuto 1, Angkana Tantituvanont 2, Dachrit Nilubol 3

Affiliations 

• PMID: 34845289
 
• PMCID: PMC8629989
 
• DOI: 10.1038/s41598-021-02444-3

Free PMC article

Abstract

Two distinct experiments (Exp) were conducted to evaluate the shedding and efficacy of 2 modified live porcine reproductive and respiratory syndrome virus (PRRSV) type 2 vaccines (MLV) when administered intramuscularly (IM) or intradermally (ID) (Exp A), and the potential of PRRSV transmission using a needle-free device (Exp B). One-hundred fifty-four, 3-week-old castrated-male, pigs were procured from a PRRSV-free herd. In Exp A, 112 pigs were randomly allocated into 4 groups of 21 pigs including IM/Ingelvac MLV (G1), IM/Prime Pac (G2), ID/Prime Pac (G3), and non-vaccination (G4). Twenty-eight remaining pigs were served as non-vaccination, age-matched sentinel pigs. G1 was IM vaccinated once with Ingelvac PRRS MLV (Ing) (Boehringer Ingelheim, Germany). G2 and G3 were IM and ID vaccinated once with a different MLV, Prime Pac PRRS (PP) (MSD Animal Health, The Netherlands), respectively. Following vaccination, an antibody response, IFN-γ-SC, and IL-10 secretion in supernatants of stimulated PBMC were monitored. Sera, tonsils, nasal swabs, bronchoalveolar lavage, urines, and feces were collected from 3 vaccinated pigs each week to 42 days post-vaccination (DPV) and assayed for the presence of PRRSV using virus isolation and qPCR. Age-matched sentinel pigs were used to evaluate the transmission of vaccine viruses and were introduced into vaccinated groups from 0 to 42 DPV. Seroconversion was monitored. In Exp B, 42 pigs were randomly allocated into 5 groups of 3 pigs each including IM/High (T1), ID/High (T2), IM/Low (T3), ID/Low (T4), and NoChal. Twenty-seven remaining pigs were left as non-challenge, age-matched sentinel pigs. The T1 and T2, and T3 and T4 groups were intranasally challenged at approximately 26 days of age with HP-PRRSV-2 at high (106) and low (103 TCID50/ml) doses, respectively. At 7 days post-challenge, at the time of the highest viremia levels of HP-PRRSV-2, T1 and T2, and T3 and T4 groups were IM and ID injected with Diluvac Forte using needles and a need-less device (IDAL 3G, MSD Animal Health, The Netherlands), respectively. Same needles or needle-less devices were used to inject the same volume of Diluvac Forte into sentinel pigs. Seroconversion of sentinels was evaluated. The results demonstrated that PP vaccinated groups (G2 and G3), regardless of the route of vaccination, had ELISA response significantly lower than G1 at 7 and 14 DPV. PP-vaccinated groups (G2 and G3) had significantly higher IFN-γ-SC and lower IL-10 secretion compared to the Ing-vaccinated group (G1). The two different MLV when administered intramuscularly demonstrated the difference in virus distribution and shedding patterns. PP-vaccinated pigs had significantly shortened viremia than the Ing-vaccinated pigs. However, ID-vaccinated pigs had lower virus distribution in organs and body fluids without virus shedding to sentinel pigs. In Exp B, regardless of the challenge dose, sentinel pigs intradermally injected with the same needle-less device used to inject challenged pigs displayed no seroconversion. In contrast, sentinel pigs intramuscularly injected with the same needle used to inject challenged pigs displayed seroconversion. The results demonstrated the transmission of PRRSV by using a needle, but not by using a needle-less device. In conclusion, our results demonstrated that ID vaccination might represent an alternative to improve vaccine efficacy and safety, and may be able to reduce the shedding of vaccine viruses and reduce the iatrogenic transfer of pathogens between animals with shared needles.

© 2021. The Author(s).

PRRS Surveillance in breeding herds and nurseries using tongue tips

 Vet Sci

. 2021 Nov 2;8(11):259.

 doi: 10.3390/vetsci8110259.

Porcine Reproductive and Respiratory Syndrome Surveillance in breeding Herds and Nurseries Using Tongue Tips from Dead Animals

Jordi Baliellas 1, Elena Novell 1, Vicens Enric-Tarancón 1, Carles Vilalta 2, Lorenzo Fraile 3 4

Affiliations 

Affiliations

• 1Grup de Sanejament Porcí, 25192 Lleida, Spain.
• 2Upnorth Analytics, Arbeca, 25140 Lleida, Spain.
• 3Agrotecnio Center, 25198 Lleida, Spain.
• 4Departament de Ciència Animal, ETSEA, University de Lleida, 25198 Lleida, Spain.

• PMID: 34822632
 
• PMCID: PMC8625958
 
• DOI: 10.3390/vetsci8110259

Free PMC article

Abstract

The detection capacity of Porcine Reproductive and Respiratory Syndrome virus (PRRSV) in tongues from dead animals in breeding herds (stillborns and piglets dying during the lactating period) and nursery farms (naturally dead animals) for PRRSV surveillance was evaluated. The samples were selected if pairs of serum and tongues were available from 2018 to 2020. Serum (pools of five) and exudate from tongues (one bag) were analyzed by PRRSV RT-PCR. The agreement between the serum sample procedure versus tongues exudate was assessed using a concordance test (Kappa statistic) at batch level. A total of 32 submissions, corresponding to 14 farms, had PRRSV diagnostic information for serum and tongues exudate. The overall agreement of batch classification as positive or negative, based on RT-PCR PRRSV results, between serum and tongue exudate of the 32 pairs was 76.9%. Cohen's Kappa was 0.55. The main discrepancy came from the presence of positive samples in tongues exudate and not in serum, suggesting that tongue exudate to monitor PRRSV seems to be more sensitive than serum. These results suggest that this sample procedure could be also used for PRRSV surveillance and monitoring.

Keywords: PRRSV; monitoring; swine; tongues exudate.

 Front Vet Sci

. 2021 Nov 5;8:769312.

 doi: 10.3389/fvets.2021.769312. eCollection 2021.

Next Generation of Voluntary PRRS Virus Regional Control Programs

Edison S Magalhães 1, Jeffrey J Zimmerman 1, Derald J Holtkamp 1, Dyneah M Classen 2, Douglas D Groth 2, Lauren Glowzenski 3, Reid Philips 4, Gustavo S Silva 1, Daniel C L Linhares 1

Affiliations 

Affiliations

• 1Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.
• 2Carthage Veterinary Service, Ltd., Carthage, IL, United States.
• 3TriOak Foods Inc., Oakville, IA, United States.
• 4Boehringer Ingelheim Animal Health USA Inc., Atlanta, GA, United States.

• PMID: 34805344
 
• PMCID: PMC8602550
 
• DOI: 10.3389/fvets.2021.769312

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) became pandemic in the 1980's and today remains one of the most significant pathogens of the global swine industry. At the herd level, control of PRRSV is complicated by its extreme genetic diversity and its ability to persist in pigs, despite an active immune response. Ultimately, PRRSV control or elimination requires the coordination and active cooperation of producers and veterinarians at the regional level. Early voluntary PRRSV regional control programs focused on routine diagnostic testing and voluntary data-sharing regarding the PRRSV status of participants' herds, but no pre-defined action plans or decision trees were developed to secure project successes (or recover from failures). Given that control of PRRSV is paramount to producer profitability, we propose a coordinated approach for detecting, controlling, and ultimately eliminating wild-type PRRSV from herds participating in regional projects. Fundamental to project success is real-time, multi-platform communication of all data, information, and events that concern the regional project and project participants. New to this approach is the concept of agreed-upon action plans to be implemented by project participants in response to specific events or situations. The simultaneous and coordinated implementation of these strategies allows for early detection of wild-type PRRSV virus introductions and rapid intervention based on agreed-upon response plans. An example is given of a project in progress in the Midwest USA.

Keywords: PRRS (porcine reproductive and respiratory syndrome virus); elimination; monitoring; regional; swine.

Copyright © 2021 Magalhães, Zimmerman, Holtkamp, Classen, Groth, Glowzenski, Philips, Silva and Linhares.

Whole-herd risk factors associated with wean-to-finish mortality (in the US)

 Prev Vet Med

. 2021 Nov 18;198:105545.

 doi: 10.1016/j.prevetmed.2021.105545.Online ahead of print.

Whole-herd risk factors associated with wean-to-finish mortality under the conditions of a Midwestern USA swine production system

Edison S Magalhães 1, Jeffrey J Zimmerman 1, Pete Thomas 2, Cesar A A Moura 2, Giovani Trevisan 1, Derald J Holtkamp 1, Chong Wang 3, Christopher Rademacher 1, Gustavo S Silva 1, Daniel C L Linhares 4

Affiliations 

• PMID: 34801793
 
• DOI: 10.1016/j.prevetmed.2021.105545

Abstract

Swine wean-to-finish (W2F) mortality is a multifactorial, dynamic process and a key performance indicator of commercial swine production. Although swine producers typically capture the relevant data, analysis of W2F mortality risk factors is often hindered by the fact that, even if data is available, they are typically in different formats, non-uniform, and dispersed among multiple unconnected databases. In this study, an automated framework was created to link multiple data streams to specific cohorts of market animals, including sow farm productivity parameters, sow farm and growing pig health factors, facilities, management factors, and closeout data from a Midwestern USA production system. The final dataset (master-table) contained breeding-to-market data for 1,316 cohorts of pigs marketed between July 2018 and June 2019. Following integration into a master-table, continuous explanatory variables were categorized into quartiles averages, and the W2F mortality was log-transformed, reporting geometric mean mortality of 8.69 % for the study population. Further, univariate analyses were performed to identify individual variables associated with W2F mortality (p < 0.10) for further inclusion in a multivariable model, where model selection was applied. The final multivariable model consisted of 13 risk factors and accounted for 68.2 % (R2) of the variability of the W2F mortality, demonstrating that sow farm health and performance are closely linked to downstream W2F mortality. Higher sow farm productivity was associated with lower subsequent W2F mortality and, conversely, lower sow farm productivity with higher W2F mortality e.g., groups weaned in the highest quartiles for pre-weaning mortality and abortion rate had 13.5 %, and 12.5 %, respectively, which was statistically lower than the lowest quartiles for the same variables (10.5 %, and 10.6 %). Moreover, better sow farm health status was also associated with lower subsequent W2F mortality. A significant difference was detected in W2F mortality between epidemic versus negative groups for porcine reproductive and respiratory syndrome virus (15.4 % vs 8.7 %), and Mycoplasma hyopneumoniae epidemic versus negative groups (13.7 % vs 9.9 %). Overall, this study demonstrated the application of a whole-herd analysis by aggregating information of the pre-weaning phase with the post-weaning phase (breeding-to-market) to identify and measure the major risk factors of W2F mortality.

Keywords: Mortality; Risk factors; Swine; Wean-to-finish; Whole-herd.