Feasibility of oral fluid collection from pre-weaning piglets

. 2020 Feb 13;9:100099.

 doi: 10.1016/j.vas.2020.100099. eCollection 2020 Jun.

Feasibility of pooled oral fluid collection from pre-weaning piglets using cotton ropes

Gwenaël Boulbria 1, Valérie Normand 1, Mily Leblanc-Maridor 2, Catherine Belloc 2, Pauline Berton 1, Franck Bouchet 1, Arnaud Lebret 1

Affiliations

• 1Porc.Spective Swine Vet Practice, ZA de Gohélève, 56920 Noyal-Pontivy, France.
• 2BIOEPAR, INRA, Oniris, Université Bretagne Loire, 44307 Nantes, France.

• PMID: 32734109
 
• PMCID: PMC7386738
 
• DOI: 10.1016/j.vas.2020.100099

Free PMC article

Abstract

Collection of pooled oral fluid (OF) by allowing pigs to chew on a cotton rope is an alternative to blood sampling. However, little is known about the applicability of this method to suckling piglets. The objectives of the present study were to describe the spontaneous interaction of suckling piglets with a rope and to investigate the influence of a rope pre-exposure on the success rate of sampling. We studied the interaction dynamics of 21 and 28 days-old suckling piglets with a cotton rope presented for 30 min. Ropes were manually wrung out inside plastic bags to release the oral fluid. A total of 49 litters were included. Percentages of success of pooled OF collection for 28-day-old, 21-day-old and 21-day-old pre-exposed litters were 82%, 62% and 100%, respectively. The mean volume collected did not differ between groups. Without pre-exposure, 84.7% and 95% of piglets interacted spontaneously with the rope at 21 and 28 days of age, respectively. The latency between rope presentation and interaction was highly variable between piglets within litters: from < 10 s to 30 min. Among piglets having interacted with the rope, the interaction lasted for at least 60 s for 90% and 91.4% of 21 and 28-day-old piglets, respectively. Pooled OF collection is achievable prior to weaning in piglets of at least 21 days of age. Pooled OF sampling is representative at litter level if collection is successful. In order to improve the success rate of collection, pre-exposing the piglets with a rope one day prior to sampling is effective.

Keywords: Diagnostic; Disease surveillance; Oral fluid; Pig; Suckling piglets.

© 2020 The Author(s).

. 2020 Jun 14.

 doi: 10.1111/tbed.13682. Online ahead of print.

Use of a Demonstration Project to Evaluate Viral Survival in Feed: Proof of Concept

Scott Dee 1, Apoorva Shah 2, Roger Cochrane 1, Travis Clement 3, Aaron Singrey 3, Roy Edler 1, Gordon Spronk 1, Megan Niederwerder 4, Eric Nelson 3

PMID: 32536022

 

DOI: 10.1111/tbed.13682

Abstract

In 2014, the hypothesis that feed ingredients could serve as vehicles for the transport and transmission of viral pathogens was proposed and evaluated by multiple investigators under laboratory conditions. In an attempt to validate these data, we used a demonstration project to test whether three significant viruses of swine could survive in feed ingredients under real-world shipping conditions. Samples of soybean meal (organic and conventional), lysine, choline, and vitamin A were spiked with a mixture of PRRSV 174, PEDV, and SVA and transported for 21 days in the trailer of a commercial transport vehicle, encompassing 14 states and 9741 km. Samples were tested for viral genome and viability at the end of the transit period. Regarding viability, PRRSV, PEDV and SVA were all detected as infectious in bioassays following inoculation with both soy products. In addition, viable PRRSV and SVA were detected by bioassay pigs inoculated with samples of vitamin A and infectious SVA was detected in pigs inoculated with samples of lysine and choline. These results provide further evidence that select viral pathogens of pigs can survive in certain feed ingredients during commercial transit.

Keywords: animal feed; demonstration project; proof of concept; swine viral diseases.

This article is protected by copyright. All rights reserved.

Studies on Heterologous Protection Between Japanese PRRSV-1 and PRRSV-2

. 2020 May 22.

 doi: 10.1292/jvms.20-0122. Online ahead of print.

Studies on Heterologous Protection Between Japanese Type 1 and Type 2 Porcine Reproductive and Respiratory Syndrome Virus Isolates

Hiroshi Iseki 1, Kenji Kawashima 1, Michihiro Takagi 1, Tomoyuki Shibahara 2 3, Masaji Mase 1 4

Affiliations

• 1Division of Viral Disease and Epidemiology, National Institute of Animal Health, National Agriculture and Food Research Organization.
• 2Division of Pathology and Pathophysiology, National Institute of Animal Health, National Agriculture and Food Research Organization.
• 3Department of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University.
• 4United Graduate School of Veterinary Sciences, Gifu University.

• PMID: 32448816
 
• DOI: 10.1292/jvms.20-0122

Abstract

The objective of the present study was to evaluate the cross-protective immunity between type 1 and type 2 porcine reproductive and respiratory syndrome virus (PRRSV) isolates in growing pigs. Japanese type 1 PRRSV, first isolated from a pig with respiratory disorders in a farm in 2009, exhibits unique genetic characteristics. The pathogenicity of a Japanese standard strain of type 2 PRRSV, EDRD1, in pigs immunized by the type 1 PRRSV isolate, Jpn EU 4-37 was determined by evaluating clinical signs, viremia, antibody response, and pathological lesions. Similarly, we evaluated the pathogenicity of Jpn EU 4-37 in pigs immunized by EDRD1 and compared the cross-protective immunity between these isolates. The EDRD1 challenge after Jpn EU 4-37 inoculation reduced viral clearance and shedding in pigs, compared to those treated with the EDRD1 single infection. On the other hand, the pathogenicity of Jpn EU 4-37 after EDRD1 infection did not differ significantly compared to non-immunized pigs treated with Jpn EU 4-37. Therefore, exposure to Jpn EU 4-37 could not induce enough immunity to reduce the viremia against subsequent infection by type 2 PRRSV. However, the immunity induced by Jpn EU 4-37 infection may play a role in reducing viremia caused by type 2 PRRSV. Moreover, the immunity induced by the EDRD1 and other genetically related viruses, which are broadly distributed in Japan, may not contribute to cross-protection against Jpn EU 4-37 as an emerging virus.

Keywords: immunity; pig; porcine reproductive and respiratory syndrome virus.

Practical Aspects of PRRSV Detection in Processing Fluids

. 2020 May 4;180:105021. doi: 10.1016/j.prevetmed.2020.105021.Online ahead of print. Practical Aspects of PRRSV RNA Detection in Processing Fluids Collected in Commercial Swine Farms
Will A López 1, Jeffrey J Zimmerman 2, Phillip C Gauger 2, Karen M Harmon 2, Laura Bradner 2, Min Zhang 3, Luis Giménez-Lirola 2, Alejandro Ramirez 2, Jean Paul Cano 1, Daniel C L Linhares 4

• 1

• Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Lloyd Veterinary Medical Center, 1809 S Riverside Dr., Ames, IA 50011-3619, United States; PIC North America, 100 Bluegrass Commons Blvd #2200, Hendersonville, TN 37075, United States.

• 2

• Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Lloyd Veterinary Medical Center, 1809 S Riverside Dr., Ames, IA 50011-3619, United States.

• 3

• Department of Statistics, College of Liberal Arts and Sciences, Iowa State University, Ames, Iowa 50011, United States.

• 4

• Veterinary Diagnostic and Production Animal Medicine Department, College of Veterinary Medicine, Iowa State University, Lloyd Veterinary Medical Center, 1809 S Riverside Dr., Ames, IA 50011-3619, United States. Electronic address: linhares@iastate.edu.

• PMID: 32428814
 
• DOI: 10.1016/j.prevetmed.2020.105021

Abstract

Processing fluid samples are easily collected under field conditions and provide the means to test more piglets more frequently in a practical way, thereby improving PRRSV surveillance. However, a deeper understanding of the diagnostic characteristics of this newly described sample type is still required. Therefore, the objective of this field-based study was to determine the relationship between viremic piglets and the detection of PRRSV RNA in processing fluid samples. In two PRRSV-positive breeding herds, processing fluids (n = 77) and individual piglet serum samples (n = 834) were collected from 77 litters in three sampling events and tested for PRRSV RNA. Among the 77 litters in the study, 55 litters (71.4%) contained no viremic piglets and processing fluids tested negative for PRRSV RNA. Among the 22 (28.6%) litters with ≥1 viremic piglets, 10 litters contained a single viremic piglet and 5 of the 10 processing fluids from this group tested positive for PRRSV RNA. Based on a fitted mixed effects logistic regression model, the probability of detecting PRRSV RNA in processing fluids was highly dependent on the number of viremic piglets contributing to the sample. When the within-litter prevalence was ≥39%, the probability of detecting PRRSV RNA in processing fluids was ≥95%. By extension, the results suggest that pooling processing fluids from several litters increases the probability of PRRSV RNA detection because of the greater likelihood of including multiple litters each with ≥1 viremic piglets. In contemporary breeding herds that use processing fluid samples for PRRSV surveillance, the diagnostic costs associated with testing 100% of the processing-age piglet population can be estimated at €0.077 ($0.086 USD) per pig weaned. In contrast, to achieve an equivalent testing coverage with the use of individual piglet serum samples, the diagnostic costs associated would be €4.48 ($5.00 USD) per pig weaned. Processing fluid represents a practical, reliable and efficient method to surveil breeding herds for PRRSV because it allows for continuous surveillance at a low cost.

Keywords: Monitoring; PRRS virus; Processing fluids; Surveillance; Swine.

Copyright © 2020 Elsevier B.V. All rights reserved.

Understanding and interpreting PRRSV diagnostics in the context of “disease transition stages”

Author links open overlay panelAlexandra Henao-Diaz  JuJi  Luis Giménez-Lirola  David H. Baum. Jeffrey Zimmerman

Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011. USA

https://doi.org/10.1016/j.rvsc.2020.04.023

Highlights

•

PRRSV infection is characterized by changes in its tissue distribution over time.

•

Therefore, the rate of PRRSV detection varies over time by specimen-assay selection.

•

The choice of specimen-assay must be tailored to specific PRRSV testing objectives.

Abstract

Herein we review broad issues that affect test performance for agents that produce persistent infections. Using PRRSV as an example, the relationship between “disease transition stages” and “diagnostic transition stages” is discussed using meta-analyses of diagnostic data (n = 4307 results) from the refereed literature to highlight the key issues. Although diagnostic technology will continue to improve, it may be concluded from the analysis that there can be no single best diagnostic approach; rather, the choice of specimen and test must be tailored to the specific testing objective. In most cases, meeting the testing objective(s) will require the use of more than one assay and/or specimen type.

Prediction of seasonal patterns of PRRSV detection in the USA

Prediction of seasonal patterns of porcine reproductive and respiratory syndrome virus RNA detection in the U.S. swine industry

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Giovani Trevisan, Leticia C. M. Linhares, Bret Crim, 

Poonam Dubey, Kent J. Schwartz, Eric R. Burrough, Chong Wang, Rodger G. Main, Paul Sundberg, Mary Thurn, Paulo T. F. Lages, Cesar A. Corzo, Jerry Torrison, Jamie Henningson, Eric Herrman, Gregg A. Hanzlicek, Ram Raghavan, Douglas Marthaler, Jon Greseth, Travis Clement, Jane Christopher-Hennings, David Muscatello, Daniel C. L. Linhares¹

First Published April 10, 2020 Research Article 

https://doi.org/10.1177/1040638720912406

Article information

bstract

We developed a model to predict the cyclic pattern of porcine reproductive and respiratory syndrome virus (PRRSV) RNA detection by reverse-transcription real-time PCR (RT-rtPCR) from 4 major swine-centric veterinary diagnostic laboratories (VDLs) in the United States and to use historical data to forecast the upcoming year’s weekly percentage of positive submissions and issue outbreak signals when the pattern of detection was not as expected. Standardized submission data and test results were used. Historical data (2015–2017) composed of the weekly percentage of PCR-positive submissions were used to fit a cyclic robust regression model. The findings were used to forecast the expected weekly percentage of PCR-positive submissions, with a 95% confidence interval (CI), for 2018. During 2018, the proportion of PRRSV-positive submissions crossed 95% CI boundaries at week 2, 14–25, and 48. The relatively higher detection on week 2 and 48 were mostly from submissions containing samples from wean-to-market pigs, and for week 14–25 originated mostly from samples from adult/sow farms. There was a recurring yearly pattern of detection, wherein an increased proportion of PRRSV RNA detection in submissions originating from wean-to-finish farms was followed by increased detection in samples from adult/sow farms. Results from the model described herein confirm the seasonal cyclic pattern of PRRSV detection using test results consolidated from 4 VDLs. Wave crests occurred consistently during winter, and wave troughs occurred consistently during the summer months. Our model was able to correctly identify statistically significant outbreak signals in PRRSV RNA detection at 3 instances during 2018.

Keywords cyclic, outbreak signal, PRRSV, prediction, swine pathogens, veterinary diagnostic laboratories