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Preis G, Benjamin NR, Murray D, Taylor EB, Copeland S, Allison G, Corzo CA. First assessment of weeks-to-negative processing fluids in breeding herds after a Senecavirus A outbreak. Porcine Health Manag 2024; 10:2. [PMID: 38183156 PMCID: PMC10768445 DOI: 10.1186/s40813-023-00353-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 12/26/2023] [Indexed: 01/07/2024] Open
Abstract
Senecavirus A (SVA) causes vesicular disease in swine and has been responsible for a rampant increase in the yearly number of foreign animal disease investigations conducted in the United States. Diagnostic investigations for SVA are typically performed by sampling animals individually, which is labor-intensive and stressful. Developing an alternative aggregate sampling method would facilitate the detection of this virus at the population level. In a preliminary study, SVA was detected in processing fluids (PF) collected in a breeding herd before and after outbreak detection. The objective of this study was to estimate the average number of weeks PF remain SVA-positive after an SVA outbreak. Ten farrow-to-wean breeding herds volunteered to participate in this studyby longitudinally collecting PF samples after an SVA outbreak was detected and submitting samples for RT-rtPCR testing. The PF samples from the 10 farms were SVA-positive for an average of 11.8 weeks after the outbreak. Here, we show that testing of PF may be a cost-effective method to detect SVA and help halt its spread in SVA-endemic regions.
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Affiliation(s)
- Guilherme Preis
- Veterinary Population Medicine Department, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA
| | - Neal R Benjamin
- The Program in Ecology, Evolution and Conservation Biology, University of Illinois Urbana- Champaign, Urbana-Champaign, IL, USA
| | | | | | | | | | - Cesar A Corzo
- Veterinary Population Medicine Department, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA.
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Osemeke OH, Cezar GA, Paiva RC, Moraes DCA, Machado IF, Magalhaes ES, Poeta Silva APS, Mil-Homens M, Peng L, Jayaraman S, Trevisan G, Silva GS, Gauger PC, Linhares DCL. A cross-sectional assessment of PRRSV nucleic acid detection by RT-qPCR in serum, ear-vein blood swabs, nasal swabs, and oral swabs from weaning-age pigs under field conditions. Front Vet Sci 2023; 10:1200376. [PMID: 37635762 PMCID: PMC10449646 DOI: 10.3389/fvets.2023.1200376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/10/2023] [Indexed: 08/29/2023] Open
Abstract
Introduction The porcine reproductive and respiratory syndrome virus (PRRSV) continues to challenge swine production in the US and most parts of the world. Effective PRRSV surveillance in swine herds can be challenging, especially because the virus can persist and sustain a very low prevalence. Although weaning-age pigs are a strategic subpopulation in the surveillance of PRRSV in breeding herds, very few sample types have been validated and characterized for surveillance of this subpopulation. The objectives of this study, therefore, were to compare PRRSV RNA detection rates in serum, oral swabs (OS), nasal swabs (NS), ear-vein blood swabs (ES), and family oral fluids (FOF) obtained from weaning-age pigs and to assess the effect of litter-level pooling on the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) detection of PRRSV RNA. Methods Three eligible PRRSV-positive herds in the Midwestern USA were selected for this study. 666 pigs across 55 litters were sampled for serum, NS, ES, OS, and FOF. RT-qPCR tests were done on these samples individually and on the litter-level pools of the swabs. Litter-level pools of each swab sample type were made by combining equal volumes of each swab taken from the pigs within a litter. Results Ninety-six piglets distributed across 22 litters were positive by PRRSV RT-qPCR on serum, 80 piglets distributed across 15 litters were positive on ES, 80 piglets distributed across 17 litters were positive on OS, and 72 piglets distributed across 14 litters were positive on NS. Cohen's kappa analyses showed near-perfect agreement between all paired ES, OS, NS, and serum comparisons (). The serum RT-qPCR cycle threshold values (Ct) strongly predicted PRRSV detection in swab samples. There was a ≥ 95% probability of PRRSV detection in ES-, OS-, and NS pools when the proportion of positive swab samples was ≥ 23%, ≥ 27%, and ≥ 26%, respectively. Discussion ES, NS, and OS can be used as surveillance samples for detecting PRRSV RNA by RT-qPCR in weaning-age pigs. The minimum number of piglets to be sampled by serum, ES, OS, and NS to be 95% confident of detecting ≥ 1 infected piglet when PRRSV prevalence is ≥ 10% is 30, 36, 36, and 40, respectively.
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Affiliation(s)
| | - Guilherme A. Cezar
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Rodrigo C. Paiva
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Daniel C. A. Moraes
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Isadora F. Machado
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Edison S. Magalhaes
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | | | - Mafalda Mil-Homens
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Li Peng
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Swaminathan Jayaraman
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Giovani Trevisan
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Gustavo S. Silva
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Phillip C. Gauger
- Veterinary Diagnostic and Production Animal Medicine Department of the College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Daniel C. L. Linhares
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
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Sanhueza JM, Schwartz M, Corzo CA, Kikuti M, Yeske P, Leuwerke B, Schelkopf A, Williams T, Feuerbach S, Johnson C, Toohill E, Tapia-Escarate D, Yang M, Schroeder D, Vilalta C. Assessing the role of sow parity on PRRSv detection by RT-qPCR through weekly processing fluids monitoring in breeding herds. Prev Vet Med 2023; 213:105854. [PMID: 36758300 DOI: 10.1016/j.prevetmed.2023.105854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 12/18/2022] [Accepted: 01/21/2023] [Indexed: 01/25/2023]
Abstract
The use of processing fluids to monitor the breeding herd's porcine reproductive and respiratory syndrome (PRRS) status has gained industry acceptance. However, little is known about PRRS virus RT-qPCR detection dynamics in processing fluids and factors that may contribute to maintain PRRS virus in the herd after an outbreak. This study aimed to describe weekly RT-qPCR processing fluid results in breeding herds after an outbreak and to evaluate the proportion of RT-qPCR positive results among parity groups. Processing tissues of 15 first parity (P1), 15 second parity (P2), and 15 third parity or higher (P3+) litters (parity groups) were collected weekly for between 19 and 46 weeks in nine breeding herds. Processing fluids were aggregated, and RT-qPCR tested by parity group weekly. Additionally, a subset of 743 processing fluid samples of litters that formed 50 parity groups, as previously described, were RT-qPCR tested individually at the litter level. The agreement between RT-qPCR results of processing fluid samples of parity groups (15 litters) and results based on individual litter testing was assessed using overall percent of agreement, Kappa statistic, and McNemar test. The association between RT-qPCR results and the parity group was evaluated using a generalized estimating equations model, after accounting for the effects of sampling week, breeding herd PRRS control strategy (i.e., open to replacements v/s closed) and herd. An autoregressive correlation structure was used to account for the repeated samplings within a herd in time. The overall agreement was 98 %, and Kappa statistic 0.955 (McNemar p = 1.0). Sensitivity of parity group processing fluid samples was estimated at 100 % (95 % CI 89-100 %), while specificity was estimated at 94 % (95 % CI 71-100 %). Although P1 aggregated litters had on average a higher proportion of RT-qPCR positive results from outbreak week 25 onwards, the proportion was not significantly different to the one observed for P2 and P3+ aggregated litters (p > 0.13). Additionally, herds that interrupted gilt entry had lower odds of PRRS RT-qPCR positivity than herds that continued entering gilts (OR = 0.35, 95 % CI 0.16-0.78). PRRS virus persistence in processing fluids was not affected by the sow parity effect in most of the breeding herds studied. No evidence of disagreement between RT-qPCR results of an aggregated sample of 15 litters and those of individual litters was observed. This level of litter aggregation testing strategy may be of particular use at the last stages of an elimination program under low PRRS virus prevalence.
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Affiliation(s)
- Juan Manuel Sanhueza
- Departamento de Ciencias Veterinarias y Salud Pública, Facultad de Recursos Naturales, Universidad Católica de Temuco, Chile.
| | | | - Cesar A Corzo
- Population Medicine Department, University of Minnesota, United States of America
| | - Mariana Kikuti
- Population Medicine Department, University of Minnesota, United States of America
| | - Paul Yeske
- Swine Vet Center, Saint Peter, MN, United States of America
| | - Brad Leuwerke
- Swine Vet Center, Saint Peter, MN, United States of America
| | - Adam Schelkopf
- Pipestone Veterinary Services, Pipestone, MN, United States of America
| | - Todd Williams
- Pipestone Veterinary Services, Pipestone, MN, United States of America
| | - Steven Feuerbach
- Pipestone Veterinary Services, Pipestone, MN, United States of America
| | - Clayton Johnson
- Carthage Veterinary Service, Ltd., Carthage, IL, United States of America
| | - Elise Toohill
- Carthage Veterinary Service, Ltd., Carthage, IL, United States of America
| | - Daniela Tapia-Escarate
- Departamento de Ciencias Veterinarias y Salud Pública, Facultad de Recursos Naturales, Universidad Católica de Temuco, Chile
| | - My Yang
- Population Medicine Department, University of Minnesota, United States of America
| | - Declan Schroeder
- Population Medicine Department, University of Minnesota, United States of America
| | - Carles Vilalta
- Unitat mixta d'Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra 08193, Catalonia, Spain; IRTA, Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra 08193, Catalonia, Spain
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Osemeke OH, VanKley N, LeFevre C, Peterson C, Linhares DCL. Evaluating oral swab samples for PRRSV surveillance in weaning-age pigs under field conditions. Front Vet Sci 2023; 10:1072682. [PMID: 36876004 PMCID: PMC9976936 DOI: 10.3389/fvets.2023.1072682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/16/2023] [Indexed: 02/05/2023] Open
Abstract
Introduction The use of serum and family oral fluids for porcine reproductive and respiratory syndrome virus (PRRSV) surveillance in weaning-age pigs has been previously characterized. Characterizing more sample types similarly offers veterinarians and producers additional validated sample options for PRRSV surveillance in this subpopulation of pigs. Oral swab sampling is relatively easy and convenient; however, there is sparse information on how it compares to the reference sample type for PRRSV surveillance under field conditions. Therefore, this study's objective was to compare the PRRSV reverse-transcription real-time polymerase chain reaction (RT-rtPCR) test outcomes of oral swabs (OS) and sera samples obtained from weaning-age pig litters. Method At an eligible breeding herd, six hundred twenty-three weaning-age piglets from 51 litters were each sampled for serum and OS and tested for PRRSV RNA by RT-rtPCR. Results and Discussion PRRSV RT-rtPCR positivity rate was higher in serum samples (24 of 51 litters, 83 of 623 pigs, with a mean cycle threshold (Ct) value of RT-rtPCR-positive samples per litter ranging from 18.9 to 32.0) compared to OS samples (15 of 51 litters, 33 of 623 pigs, with a mean Ct of RT-rtPCR positive samples per litter ranging from 28.2 to 36.9); this highlights the importance of interpreting negative RT-rtPCR results from OS samples with caution. Every litter with a positive PRRSV RT-rtPCR OS had at least one viremic piglet, highlighting the authenticity of positive PRRSV RT-rtPCR tests using OS; in other words, there was no evidence of environmental PRRSV RNA being detected in OS. Cohen's kappa analysis (Ck = 0.638) indicated a substantial agreement between both sample types for identifying the true PRRSV status of weaning-age pigs.
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Affiliation(s)
| | - Nathan VanKley
- College of Veterinary Medicine, Michigan State University, Lansing, MI, United States
| | - Claire LeFevre
- Carthage Veterinary Service, Carthage, IL, United States
| | - Christina Peterson
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
| | - Daniel C L Linhares
- Fieldepi, Iowa State University College of Veterinary Medicine, Ames, IA, United States
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