Assessment of immediate production impact following attenuated PRRS type 2 virus vaccination in swine breeding herds

• Cesar A. A. Moura,
• Clayton Johnson,
• Samuel R. Baker,
• Derald J. Holtkamp,
• Chong Wang and
• Daniel C. L. LinharesEmail authorView ORCID ID profile

Porcine Health Management20195:13

https://doi.org/10.1186/s40813-019-0120-2

©  The Author(s). 2019

• Received: 6 February 2019
• Accepted: 13 May 2019
• Published: 11 June 2019

Abstract

Background

To mitigate production impact of porcine reproductive and respiratory syndrome (PRRS) virus outbreaks, it has been common to preventively vaccinate swine breeding herds using PRRS modified live virus (MLV) vaccine. However, attenuated PRRS virus (PRRSv) may result negative impact on farm productivity. The objective of this study was to measure the immediate impact of PRRS type 2 MLV vaccine on breeding herd performance under field conditions. Eight PRRS-stable farms routinely mass vaccinating females with commercial PRRS MLV vaccines were enrolled on study. Vaccination dates were collected and weekly changes in abortions, neonatal losses, pre-weaning mortality, pigs weaned per sow, and wean-to-first-service interval were assessed for up to 6 weeks after each vaccination. A 6-week period prior to each vaccination was established as baseline. Statistical process control (SPC) analysis was conducted to detect significant productivity decreases after MLV interventions, on each farm, and a mixed regression model was used, at the aggregated data level, to assess the productivity change 6 weeks after PRRS MLV vaccinations, compared to baseline.

Results

Out of 65 herd-MLV vaccinations, SPC analysis detected increase on abortions 4 times (6.1%), on neonatal losses 7 times (10.7%), on pre-weaning mortality 2 times (3%), on wean-to-first-service interval 2 times (3%), and no change in total pigs weaned. On aggregated data analysis, there was no significant change in abortion rate, neonatal losses, number of pigs weaned per sow, and wean-to-first-service interval. However, there was an increase of 0.26% of pre-weaning mortality 2 weeks after vaccination compared to the baseline.

Conclusions

Under study conditions, individual PRRS-stable sow farms had experienced transient, and numerically small changes in productivity following PRRS type 2 MLV vaccination. There was a small increase of pre-weaning mortality 2 weeks after vaccination, but no evidence of significant production impact at aggregated data analysis for abortion rate, neonatal losses, pigs weaned per sow and wean-to-first-service interval.

Keywords

• Swine
• PRRS
• Vaccination
• MLV
• Outbreak
• Epidemiology

Automated clustering approach applied to surveillance of PRRSV field strains.

Infect Genet Evol. 2019 Apr 27. pii: S1567-1348(18)30899-2. doi: 10.1016/j.meegid.2019.04.014. [Epub ahead of print]

Evaluating an automated clustering approach in a perspective of ongoing surveillance of porcine reproductive and respiratory syndrome virus (PRRSV) field strains.

Lambert MÈ1, Arsenault J2, Audet P3, Delisle B4, D'Allaire S5.

Author information

1

Laboratoire d'épidémiologie et de médecine porcine (LEMP), Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada. Electronic address: marie-eve.lambert@umontreal.ca.

2

Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada. Electronic address: julie.arsenault@umontreal.ca.

3

Laboratoire d'épidémiologie et de médecine porcine (LEMP), Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada. Electronic address: pascal.audet@umontreal.ca.

4

Laboratoire d'épidémiologie et de médecine porcine (LEMP), Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada. Electronic address: benjamin.delisle@umontreal.ca.

5

Laboratoire d'épidémiologie et de médecine porcine (LEMP), Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec, Canada. Electronic address: sylvie.dallaire@umontreal.ca.

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) has a major economic impact on the swine industry. The important genetic diversity needs to be considered for disease management. In this regard, information on the circulating endemic strains and their dispersal patterns through ongoing surveillance is beneficial. The objective of this project was to classify Quebec PRRSV ORF5 sequences in genetic clusters and evaluate stability of clustering results over a three-year period using an in-house automated clustering system. Phylogeny based on maximum likelihood (ML) was first inferred on 3661 sequences collected in 1998-2013 (Run 1). Then, sequences collected between January 2014 and September 2016 were sequentially added into 11 consecutive runs, each one covering a three-month period. For each run, detection of clusters, which were defined as groups of ≥15 sequences having a ≥ 70% rapid bootstrap support (RBS) value, was automated in Python. Cluster stability was described for each cluster and run based on the number of sequences, RBS value, maximum pairwise distance and agreement in sequence assignment to a specific cluster. First and last run identified 29 and 33 clusters, respectively. In the last run, about 77% of the sequences were classified by the system. Most clusters were stable through time, with sequences attributed to one cluster in Run 1 stayed in the same cluster for the 11 remaining runs. However, some initial groups were further subdivided into subgroups with time, which is important for monitoring since one specific wild-type cluster increased from 0% in 2007 to 45% of all sequences in 2016. This automated classification system will be integrated into ongoing surveillance activities, to facilitate communication and decision-making for stakeholders of the swine industry.

Copyright © 2019. Published by Elsevier B.V.

KEYWORDS: 

Classification; ORF5; PRRS; Phylogeny; Surveillance

PMID:

 

31039449

 

DOI:

 

10.1016/j.meegid.2019.04.014

Prev Vet Med. 2019 Jun 1;167:128-136. doi: 10.1016/j.prevetmed.2019.03.020. Epub 2019 Apr 10.

Assessment of biosecurity practices and development of a scoring system in swine farms using item response theory.

Silva GS1, Leotti VB2, Castro SMJ2, Medeiros AAR3, Silva APSP4, Linhares DCL5, Corbellini LG6.

Author information

1

Laboratory of Veterinary Epidemiology, Faculty of Veterinary, Department of Preventive Veterinary Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Veterinary Diagnostic and Production Animal Medicine Department, Iowa State University, Ames, IA, United States.

2

Department of Statistics, Institute of Mathematics and Statistics and Post-Graduate Program of Epidemiology, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.

3

Laboratory of Veterinary Epidemiology, Faculty of Veterinary, Department of Preventive Veterinary Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Department of Agriculture and Livestock of Rio Grande do Sul (SEAPI), Porto Alegre, Brazil.

4

Laboratory of Veterinary Epidemiology, Faculty of Veterinary, Department of Preventive Veterinary Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.

5

Veterinary Diagnostic and Production Animal Medicine Department, Iowa State University, Ames, IA, United States.

6

Laboratory of Veterinary Epidemiology, Faculty of Veterinary, Department of Preventive Veterinary Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil. Electronic address: luis.corbellini@ufrgs.br.

Abstract

Brazil is the fourth largest producer and exporter of pork in the world, but has never reported yet the occurrence of some economically important diseases such as porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED). Most of the swine farms in Brazil are characterized by intensive production being part of large integrated companies, where biosecurity practices help to prevent the introduction and spread of disease-causing infectious agents. The assessment of biosecurity in farms is not straightforward because of the large number of practices that constitute an on-farm biosecurity program. It is therefore necessary to combine the measurement of several parameters in order to characterize the level of biosecurity on a given farm. Thus, the objective of the study was to develop a biosecurity score to estimate the biosecurity level (theta or θ) in swine farms using the item response theory (IRT) and explore the relationship between the scores and independent variables. The IRT is a latent trait method extensively used in other fields, and offers the advantage to quantify the latent trait, here the biosecurity level, and to identify the practices that discriminate the farms avoiding the use of extensive questionnaires and redundant questions. In this study, 604 farms were evaluated in the main swine production regions of the state of Rio Grande do Sul, Brazil. Thirty-five practices were considered in order to quantify the biosecurity level on a given farm. After a recursive process 14 practices were selected to compose the biosecurity score to estimate the biosecurity level (θ). The variables identified with greater capacity of distinguishing the farms as to their biosecurity level were if the farm has 'feed bin outside of the barn limit (external feed loading)', has 'perimetral fence around the farm or barn', and if 'transit of trucks inside the farm is prohibited'. The biosecurity level was associated with some independent variables, e.g. the farm operation type, the integrated company and some owner characteristics. In addition, the results demonstrated that biosecurity practices related to management (internal biosecurity) are adopted with higher frequency compared to segregation and sanitation practices (external biosecurity). The IRT model proved useful and valid to estimate the biosecurity level in swine farms. Moreover, the biosecurity score described here has a relatively low number of items, which makes the application of this tool easier and faster compared to other previously described biosecurity assessment.

Copyright © 2019 Elsevier B.V. All rights reserved.

KEYWORDS: 

Biosecurity assessment; Biosecurity score; Herd characteristics; Item response theory; Swine farms

PMID:

 

31027714

 

DOI:

 

10.1016/j.prevetmed.2019.03.020

PRRSV: web-based interactive tools to support surveillance and control initiatives in Canada

Porcine Health Manag. 2019 Mar 28;5:10. doi: 10.1186/s40813-019-0117-x. eCollection 2019.

Porcine reproductive and respiratory syndrome virus: web-based interactive tools to support surveillance and control initiatives.

Lambert MÈ1, Audet P1, Delisle B1, Arsenault J1, D'Allaire S1.

Author information

1

Laboratoire d'épidémiologie et de médecine porcine (LEMP), Faculty of Veterinary Medicine, Université de Montréal, St. Hyacinthe, Quebec Canada.

Abstract

BACKGROUND: 

Control of porcine reproductive and respiratory syndrome (PRRS) represents a tremendous challenge. The trend is now toward managing the disease collectively. In Quebec, area and regional control and elimination (ARC&E) initiatives started in 2011; diagnostic testing, including ORF5 sequencing, and sharing of information among stakeholders are largely promoted. At the provincial level, a data-sharing agreement was signed by Quebec swine practitioners allowing PRRS virus (PRRSV) sequences to be transferred to a database maintained by the Laboratoire d'épidémiologie et de médecine porcine (LEMP-DB). Several interactive tools were developed and are available to veterinarians to allow comparison of PRRSV ORF5 sequences within ARC&E projects or provincially while managing confidentiality issues.

RESULTS: 

Between January 1st 2010 and December 31st 2018, 4346 PRRSV ORF5 sequences were gathered into the LEMP-DB, involving 1254 sites and 43 practicing veterinarians. Approximately 34% of the submissions were from ARC&E projects. Using a novel web-based sequence comparison tool, each veterinarian has access to information on his/her client sequences and can compare each sequence with 1) commercial vaccine strains, 2) historical samples from the same site, and 3) all sequences submitted to the database over the last 4 years. Newly introduced PRRSV into breeding herds can be monitored using a new sequence comparison tool based on comparison of sequences at the provincial level. Each month, graphs providing the number of introductions per month and the yearly cumulative are updated. Between August 1st 2014 and December 31st 2018, 233 introductions were detected on 180 different breeding sites. Following a data-sharing agreement, veterinarians involved in ARC&E projects have access to an interactive mapping tool to locate pig sites, compare sequence similarity between participating sites and visualize the results on the map.

CONCLUSIONS: 

The structure developed in Quebec to collect, analyse and share sequencing data was efficient to provide useful information to the swine industry at both provincial and regional levels while dealing with confidentiality issues.

KEYWORDS: 

ARC&E; Control; Epidemiology; Molecular; ORF5; PRRS; Sequence; Similarity; Surveillance

PMID:

 

30976454

 

PMCID:

 

PMC6437942

 

DOI:

 

10.1186/s40813-019-0117-x

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Comp Immunol Microbiol Infect Dis. 2019 Apr;63:66-73. doi: 10.1016/j.cimid.2018.12.010. Epub 2019 Jan 9.

Comparison of four commercial PRRSV MLV vaccines in herds with co-circulation of PRRSV-1 and PRRSV-2.

Oh T1, Kim H1, Park KH1, Jeong J1, Yang S1, Kang I1, Chae C2.

Author information

1

Seoul National University, College of Veterinary Medicine, Department of Veterinary Pathology, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.

2

Seoul National University, College of Veterinary Medicine, Department of Veterinary Pathology, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea. Electronic address: swine@snu.ac.kr.

Abstract

The efficacy of four commercial porcine reproductive and respiratory syndrome virus (PRRSV) modified-live virus (MLV) vaccines against respiratory disease was evaluated and compared in pig farms suffering from co-infection with PRRSV-1 and PRRSV-2. All vaccinated groups on average exhibited improved growth rate compared to the unvaccinated pigs. Interestingly, the two groups vaccinated with either of the PRRSV-2 MLV vaccines had a better overall growth rate compared to the pigs vaccinated with either of the PRRSV-1 MLV vaccines. Vaccination of pigs with either of the PRRSV-1 MLV vaccines did not result in reduction of PRRSV-1 or PRRSV-2 viremia whereas vaccination of pigs with either of the PRRSV-2 MLV vaccines resulted in the reduction of PRRSV-2 viremia only. Taken together, the results of this field study demonstrate that a PRRSV-2 MLV vaccine can be efficacious against respiratory disease caused by co-infection with PRRSV-1 and PRRSV-2.

Copyright © 2019 Elsevier Ltd. All rights reserved.

KEYWORDS: 

Co-infection; Porcine reproductive and respiratory syndrome; Vaccine; Virus

PMID:

 

30961820

 

DOI:

 

10.1016/j.cimid.2018.12.010

Cellular Innate Immunity against PRRSV (and IAV)

Vet Sci. 2019 Mar 11;6(1). pii: E26. doi: 10.3390/vetsci6010026.

Cellular Innate Immunity against PRRSV and Swine Influenza Viruses.

Crisci E1,2, Fraile L3, Montoya M4.

Author information

1

Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA. ecrisci@ncsu.edu.

2

Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27607, USA. ecrisci@ncsu.edu.

3

Universitat de Lleida, 25198 Lleida, Spain. lorenzo.fraile@ca.udl.cat.

4

Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB-CSIC), 28040 Madrid, Spain. maria.montoya@cib.csic.es.

Abstract

Porcine respiratory disease complex (PRDC) is a polymicrobial syndrome that results from a combination of infectious agents, such as environmental stressors, population size, management strategies, age, and genetics. PRDC results in reduced performance as well as increased mortality rates and production costs in the pig industry worldwide. This review focuses on the interactions of two enveloped RNA viruses-porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SwIV)-as major etiological agents that contribute to PRDC within the porcine cellular innate immunity during infection. The innate immune system of the porcine lung includes alveolar and parenchymal/interstitial macrophages, neutrophils (PMN), conventional dendritic cells (DC) and plasmacytoid DC, natural killer cells, and γδ T cells, thus the in vitro and in vivo interactions between those cells and PRRSV and SwIV are reviewed. Likewise, the few studies regarding PRRSV-SwIV co-infection are illustrated together with the different modulation mechanisms that are induced by the two viruses. Alterations in responses by natural killer (NK), PMN, or γδ T cells have not received much attention within the scientific community as their counterpart antigen-presenting cells and there are numerous gaps in the knowledge regarding the role of those cells in both infections. This review will help in paving the way for future directions in PRRSV and SwIV research and enhancing the understanding of the innate mechanisms that are involved during infection with these viruses.

KEYWORDS: 

PRRSV; innate immunity; pig; swine influenza virus

PMID:

 

30862035

 

DOI:

 

10.3390/vetsci6010026

Influence of age, group size, and presence of PRRSv on oral fluids collection

Vet J. 2019 Feb;244:13-15. doi: 10.1016/j.tvjl.2018.12.005. Epub 2018 Dec 7.

Influence of age, group size and the presence of porcine reproductive and respiratory syndrome virus on the collection of oral fluids.

Graage R1, Hennig-Pauka I2, Arbinger H2, Ritzmann M3, Ladinig A2.

Author information

1

Department for Farm Animals and Veterinary Public Health, University Clinic for Swine, University of Veterinary Medicine Vienna, Vienna Vetertinaerplatz 1, A-1220 Vienna, Austria. Electronic address: rgraage@vetclinics.uzh.ch.

2

Department for Farm Animals and Veterinary Public Health, University Clinic for Swine, University of Veterinary Medicine Vienna, Vienna Vetertinaerplatz 1, A-1220 Vienna, Austria.

3

Clinic for Swine at the Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University Munich, Sonnenstrasse 16, D-85764 Oberschleißheim, Germany.

Abstract

Pen-based oral fluid (OF) samples have been approved for detecting porcine reproductive and respiratory syndrome virus (PRRSV) RNA and antibodies. The aim of the study was to investigate the influence of age, group size and the presence of PRRSV infection on sampling using pen-based OF collected by presenting pigs with a rope to chew. Samples were collected from pigs of 4/5 weeks of age, 7/8 weeks of age and 12/14 weeks of age. Subsequent PRRSV-PCR and ELISA analyses of OF and serum samples were performed. In this study, 76.5-81.9% of pigs chewed the rope. The group size had significant impact on the pig-rope-interaction (P=0.047). OF and serum had an almost perfect and significant agreement for the detection of antibodies (κ=0.829, P<0.001) and a fair and not significant agreement (κ=0.347, P=0.75) for the detection PRRSV-genome.

Copyright © 2018 Elsevier Ltd. All rights reserved.

KEYWORDS: 

ELISA; Oral fluid; PCR; PRRSV; Rope; Surveillance

PMID:

 

30825888

 

DOI:

 

10.1016/j.tvjl.2018.12.005