Survival of PRRSV and PEDV in compost formed from preprocessed carcasses

 Transbound Emerg Dis

Survival of swine pathogens in compost formed from preprocessed carcasses

Brent Pepin 1, Todd Williams 1, Dale Polson 2, Phillip Gauger 3, Scott Dee 1

 doi: 10.1111/tbed.13876.

Abstract

An introduction of a Foreign Animal Disease (FAD) like African Swine Fever Virus (ASF) would be financially devastating. For example, ASF, a highly contagious pathogen with high mortality rates, is a World Health Organization reportable disease that has recently been spreading across Asia and Europe. Control of ASF would likely require mass euthanasia of infected and exposed animals similar to the United Kingdom's elimination of Foot and Mouth Disease (FMD). Subsequent disposal of infectious carcasses must adequately eliminate the virus and prevent further transmission of the disease. Although composting swine carcasses is widely used throughout the industry, limited data is available describing pathogen survival or elimination during this process. While current methods have evaluated the composting of swine carcasses under temperature-controlled settings, they have not considered the effects of adverse weather conditions (e.g., cold winter conditions) where composting is routinely performed. This study utilized preprocessing (grinding) of swine carcasses prior to composting, which decreases the amount of required carbon material and land space. The ability of composting to reduce the level of viral nucleic acid during cold weather conditions and the risk of environmental contamination that may occur during preprocessing was evaluated. In this study, pigs challenged with Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and Porcine Epidemic Diarrhea Virus (PEDV), common domestic diseases, before euthanasia provided infectious carcasses containing pathogen surrogates. Composting of preprocessed carcasses achieved adequate temperatures necessary to eliminate FAD and common swine pathogens during cold weather conditions (monitored by compost temperature over time, virus diagnostic testing, and swine bioassay for PRRSV and PEDV). Under the conditions of this study, composting preprocessed carcasses presents minimal risk to air and groundwater contamination. In conclusion, composting preprocessed euthanized swine under adverse weather conditions is a safe and feasible option for mass disposal of infected carcasses.

Keywords: Compost; Grinding; PEDV; PRRSV; Pathogen; Pre-processing.

This article is protected by copyright. All rights reserved.

Spatial relative risk and factors associated with PRRS outbreaks in US breeding herds

 Prev Vet Med

. 2020 Sep 1;183:105128.

 doi: 10.1016/j.prevetmed.2020.105128. Online ahead of print.

Spatial relative risk and factors associated with porcine reproductive and respiratory syndrome outbreaks in United States breeding herds

Juan M Sanhueza 1, Mark A Stevenson 2, Carles Vilalta 3, Mariana Kikuti 4, Cesar A Corzo 4

• PMID: 32937200
 
• DOI: 10.1016/j.prevetmed.2020.105128

Abstract

Details of incident cases of porcine reproductive and respiratory syndrome (PRRS) in United States breeding herds were obtained from the Morrison's Swine Health Monitoring Project. Herds were classified as cases if they reported an outbreak in a given season of the year and non-cases if they reported it in a season other than the case season or if they did not report a PRRS outbreak in any season. The geographic distribution of cases and non-cases was compared in each season of the year. The density of farms that had a PRRS outbreak during summer was higher in Southern Minnesota and Northwest-central Iowa compared to the density of the underlying population of non-case farms. This does not mean that PRRS outbreaks are more frequent during summer in absolute terms, but that there was a geographical clustering of herds breaking during summer in this area. Similar findings were observed in autumn. In addition, the density of farms reporting spring outbreaks was higher in the Southeast of the United States compared to that of the underlying population of non-case farms. A similar geographical clustering of PRRS outbreaks was observed during winter in the Southeast of the United States. Multivariable analyses, adjusting for the effect of known confounders, showed that the incidence rate of PRRS was significantly lower during winter and autumn during the porcine epidemic diarrhea (PED) epidemic years (2013-2014), compared to PRRS incidence rates observed during the winter and autumn of PED pre-epidemic years (2009-2012). After 2014, an increase in the incidence rate of PRRS was observed during winter and spring but not during autumn or summer. Pig dense areas were associated with a higher incidence rate throughout the year. However, this association tended to be stronger during the summer. Additionally, herds with ≥2500 sows had an increased incidence rate during all seasons except spring compared to those with <2500 sows. PRRS incidence was lower in year-round air-filtered herds compared to non-filtered herds throughout the year. We showed that not only the spatial risk of PRRS varies regionally according to the season of the year, but also that the effect of swine density, herd size and air filtering on PRRS incidence may also vary according to the season of the year. Further studies should investigate regional and seasonal drivers of disease. Breeding herds should maintain high biosecurity standards throughout the year.

Keywords: Factors; Incidence; PRRS; Risk; Sow; Spatial.

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

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.