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Strengthening Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Detection in Breeding Herds: Development and Assessment of Processing Fluids Sampling Strategies = = Fortalecimiento de la deteccion del virus del sindrome respiratorio y reproductivo porcino (PRRSV) en rebanos de cria: desarrollo y evaluacion de estrategias de muestreo de fluidos de procesamiento.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Strengthening Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Detection in Breeding Herds: Development and Assessment of Processing Fluids Sampling Strategies =/
其他題名:	Fortalecimiento de la deteccion del virus del sindrome respiratorio y reproductivo porcino (PRRSV) en rebanos de cria: desarrollo y evaluacion de estrategias de muestreo de fluidos de procesamiento.
作者:	Lopez Lopez, Will Alberto.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2020,
面頁冊數:	114 p.
附註:	Source: Dissertations Abstracts International, Volume: 82-01, Section: B.
Contained By:	Dissertations Abstracts International82-01B.
標題:	Epidemiology. -
電子資源:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27955638
ISBN:	9798662379992

Strengthening Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Detection in Breeding Herds: Development and Assessment of Processing Fluids Sampling Strategies = = Fortalecimiento de la deteccion del virus del sindrome respiratorio y reproductivo porcino (PRRSV) en rebanos de cria: desarrollo y evaluacion de estrategias de muestreo de fluidos de procesamiento.
Lopez Lopez, Will Alberto.

Strengthening Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Detection in Breeding Herds: Development and Assessment of Processing Fluids Sampling Strategies =Fortalecimiento de la deteccion del virus del sindrome respiratorio y reproductivo porcino (PRRSV) en rebanos de cria: desarrollo y evaluacion de estrategias de muestreo de fluidos de procesamiento. - Ann Arbor : ProQuest Dissertations & Theses, 2020 - 114 p.

Source: Dissertations Abstracts International, Volume: 82-01, Section: B.

Thesis (Ph.D.)--Iowa State University, 2020.

This item must not be sold to any third party vendors.

Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be an outstanding health issue for the global swine production sector. The ability to accurately track the virus and characterize disease status between and within pig populations in today's swine industry is of high importance for the sustainability of the business. Towards that end, the collection of the necessary information to support PRRSV control and elimination programs is dependent upon continuous and reliable monitoring and surveillance systems (MOSS) that need to be both particularly practical and affordable. The issue addressed in this dissertation is the improvement of current PRRSV MOSS employed in breeding herds, through the development of a new sampling method called processing fluids and the assessment and optimization of its applicability for PRRSV RNA and antibody detection in breeding herds. The rational series of studies described below will address the issue pointed above.Chapter Two introduced the processing fluids method as a new tool for PRRSV monitoring in breeding herds. This field study served as a proof of concept for this new sampling technique. Matching sets of processing fluids and serum samples obtained under field conditions from breeding herds, proved that PRRSV can be detected in processing fluids by reverse transcription quantitative polymerase chain reaction (RT-qPCR) at a higher frequency than the standard method of bleeding 30 pigs and testing the serum in pools of five (83.3% vs 66.6%). Moreover, IgG antibody detection was assessed and confirmed, and ORF5 sequencing was also achievable.In Chapter Three, the probability of PRRSV RNA detection in processing fluid samples as a function of the within-litter prevalence of the virus was evaluated and compared with that of serum samples obtained from randomly selected piglets (1, 2, 3 or 4 per litter). Results suggest that when within-litter prevalence is ≥ 50% the probability of PRRSV RNA detection in processing fluids would be higher than that of randomly selected individual piglets (i.e., ≥ 99%). Additional comparisons between the processing fluids sampling approach and the standard PRRSV monitoring scheme using 30 serum samples were made through computer simulation (bootstrapping), giving as result an overall probability of PRRSV detection of 100% when using processing fluids vs 92.1% using 30 serum samples. Chapter Three also looked at processing fluids pooling potential, demonstrating that PRRSV detection was 100% achievable in processing fluids within a low prevalence scenario. The test of a massive pool with only 8% PRRSV-positive pigs (i.e., only 67 viremic pigs out of 834 total pigs in the pool) yielded a strong positive RT-qPCR quantification cycle (Cq) response (Cq = 22.0). The two main objectives of the study described in Chapter Four were, 1) to evaluate the effect of pre-testing conditions of processing fluid samples on RT-qPCR testing results, such as temperatures and time length for sample storage and protocols for nucleic acid extraction and, 2) the adaptation of a commercial PRRSV serum antibody assay (ELISA) for the detection of three different anti-PRRSV antibody (Ab) isotypes (IgM, IgA and IgG) in processing fluids and to establish the test sample-to-positive ratio (S/P) cut-off, i.e., the point that best discriminated positive and negative samples. The two studies within this chapter revealed that, 1) PRRS virus in processing fluid samples would be stable under refrigeration for periods of time of up to 14 days. Also, prolonged exposure to room and higher temperatures would have, correspondingly, a mild and strong detrimental effect on the viral RNA within processing fluid samples, therefore, affecting RT-qPCR testing results. Results also suggested no effect in testing results between the four different commercial RNA purification kits. 2) The results obtained for PRRSV IgG Ab isotype showed perfect discrimination between positive and negative processing fluid samples using a cut-off value of 0.5. Results with the PRRS IgA and IgM ELISA for processing fluids showed low to poor discrimination and therefore would need additional research and optimization. Chapter Five models the effect of pooling processing fluid samples on the probability of PRRSV RNA detection under a low prevalence scenario and establishes the limit for pooling processing fluids where the probability of PRRSV detection would not fall under 95% threshold. PRRSV RNA detection in pooled processing fluid samples of multiple litters (e.g., 29 to 65), is feasible when at least one pig within a given litter in the pool is positive for PRRSV with a RT-qPCR Cq value  29. Thus, demonstrating that, detection limits for pooling processing fluid samples might be dependent on the magnitude of viremia of the pig(s) within the sample. These findings could be useful for designing accurate and reliable processing fluid-based sampling protocols.

ISBN: 9798662379992Subjects--Topical Terms:

568544
Epidemiology.
Subjects--Index Terms:

Detection

Strengthening Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Detection in Breeding Herds: Development and Assessment of Processing Fluids Sampling Strategies = = Fortalecimiento de la deteccion del virus del sindrome respiratorio y reproductivo porcino (PRRSV) en rebanos de cria: desarrollo y evaluacion de estrategias de muestreo de fluidos de procesamiento.
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245 1 0 $a Strengthening Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Detection in Breeding Herds: Development and Assessment of Processing Fluids Sampling Strategies = $b Fortalecimiento de la deteccion del virus del sindrome respiratorio y reproductivo porcino (PRRSV) en rebanos de cria: desarrollo y evaluacion de estrategias de muestreo de fluidos de procesamiento.
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500 $a Source: Dissertations Abstracts International, Volume: 82-01, Section: B.
500 $a Advisor: Linhares, Daniel C. L.
502 $a Thesis (Ph.D.)--Iowa State University, 2020.
506 $a This item must not be sold to any third party vendors.
520 $a Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be an outstanding health issue for the global swine production sector. The ability to accurately track the virus and characterize disease status between and within pig populations in today's swine industry is of high importance for the sustainability of the business. Towards that end, the collection of the necessary information to support PRRSV control and elimination programs is dependent upon continuous and reliable monitoring and surveillance systems (MOSS) that need to be both particularly practical and affordable. The issue addressed in this dissertation is the improvement of current PRRSV MOSS employed in breeding herds, through the development of a new sampling method called processing fluids and the assessment and optimization of its applicability for PRRSV RNA and antibody detection in breeding herds. The rational series of studies described below will address the issue pointed above.Chapter Two introduced the processing fluids method as a new tool for PRRSV monitoring in breeding herds. This field study served as a proof of concept for this new sampling technique. Matching sets of processing fluids and serum samples obtained under field conditions from breeding herds, proved that PRRSV can be detected in processing fluids by reverse transcription quantitative polymerase chain reaction (RT-qPCR) at a higher frequency than the standard method of bleeding 30 pigs and testing the serum in pools of five (83.3% vs 66.6%). Moreover, IgG antibody detection was assessed and confirmed, and ORF5 sequencing was also achievable.In Chapter Three, the probability of PRRSV RNA detection in processing fluid samples as a function of the within-litter prevalence of the virus was evaluated and compared with that of serum samples obtained from randomly selected piglets (1, 2, 3 or 4 per litter). Results suggest that when within-litter prevalence is ≥ 50% the probability of PRRSV RNA detection in processing fluids would be higher than that of randomly selected individual piglets (i.e., ≥ 99%). Additional comparisons between the processing fluids sampling approach and the standard PRRSV monitoring scheme using 30 serum samples were made through computer simulation (bootstrapping), giving as result an overall probability of PRRSV detection of 100% when using processing fluids vs 92.1% using 30 serum samples. Chapter Three also looked at processing fluids pooling potential, demonstrating that PRRSV detection was 100% achievable in processing fluids within a low prevalence scenario. The test of a massive pool with only 8% PRRSV-positive pigs (i.e., only 67 viremic pigs out of 834 total pigs in the pool) yielded a strong positive RT-qPCR quantification cycle (Cq) response (Cq = 22.0). The two main objectives of the study described in Chapter Four were, 1) to evaluate the effect of pre-testing conditions of processing fluid samples on RT-qPCR testing results, such as temperatures and time length for sample storage and protocols for nucleic acid extraction and, 2) the adaptation of a commercial PRRSV serum antibody assay (ELISA) for the detection of three different anti-PRRSV antibody (Ab) isotypes (IgM, IgA and IgG) in processing fluids and to establish the test sample-to-positive ratio (S/P) cut-off, i.e., the point that best discriminated positive and negative samples. The two studies within this chapter revealed that, 1) PRRS virus in processing fluid samples would be stable under refrigeration for periods of time of up to 14 days. Also, prolonged exposure to room and higher temperatures would have, correspondingly, a mild and strong detrimental effect on the viral RNA within processing fluid samples, therefore, affecting RT-qPCR testing results. Results also suggested no effect in testing results between the four different commercial RNA purification kits. 2) The results obtained for PRRSV IgG Ab isotype showed perfect discrimination between positive and negative processing fluid samples using a cut-off value of 0.5. Results with the PRRS IgA and IgM ELISA for processing fluids showed low to poor discrimination and therefore would need additional research and optimization. Chapter Five models the effect of pooling processing fluid samples on the probability of PRRSV RNA detection under a low prevalence scenario and establishes the limit for pooling processing fluids where the probability of PRRSV detection would not fall under 95% threshold. PRRSV RNA detection in pooled processing fluid samples of multiple litters (e.g., 29 to 65), is feasible when at least one pig within a given litter in the pool is positive for PRRSV with a RT-qPCR Cq value  29. Thus, demonstrating that, detection limits for pooling processing fluid samples might be dependent on the magnitude of viremia of the pig(s) within the sample. These findings could be useful for designing accurate and reliable processing fluid-based sampling protocols.
520 $a El virus del sindrome respiratorio y reproductivo porcino (PRRSV) continua siendo un problema de salud sobresaliente para el sector global de produccion porcina. La capacidad de rastrear con precision el virus y caracterizar el estado de la enfermedad entre y dentro de las poblaciones de cerdos en la industria porcina actual es de gran importancia para la sostenibilidad del negocio. Con ese fin, la recopilacion de la informacion necesaria para apoyar los programas de control y eliminacion de PRRSV depende de sistemas de monitoreo y vigilancia (MOSS) continuos y confiables que deben ser tanto practicos como asequibles. El tema abordado en esta disertacion es la mejora del MOSS actual de PRRSV empleado en rebanos de cria, a traves del desarrollo de un nuevo metodo de muestreo llamado fluidos de procesamiento y la evaluacion y optimizacion de su aplicabilidad para la deteccion de ARN de PRRSV y anticuerpos en rebanos de cria. La serie racional de estudios descritos a continuacion abordara el problema senalado anteriormente.El Capitulo Dos introdujo el metodo de procesamiento de fluidos como una nueva herramienta para el monitoreo de PRRSV en rebanos reproductores. Este estudio de campo sirvio como prueba de concepto para esta nueva tecnica de muestreo. Conjuntos coincidentes de fluidos de procesamiento y muestras de suero obtenidas en condiciones de campo de rebanos reproductores, demostraron que el PRRSV se puede detectar en los fluidos de procesamiento por reaccion de cadena de polimerasa cuantitativa de transcripcion inversa (RT-qPCR) a una frecuencia mas alta que el metodo estandar de sangrado de 30 cerdos y probar el suero en grupos de cinco (83.3% vs 66.6%). Ademas, la deteccion de anticuerpos IgG se evaluo y confirmo, y la secuenciacion de ORF5 tambien fue posible.En el Capitulo Tres, se evaluo la probabilidad de deteccion de ARN de PRRSV en el procesamiento de muestras de fluidos en funcion de la prevalencia del virus dentro de la camada y se comparo con la de las muestras de suero obtenidas de lechones seleccionados al azar (1, 2, 3 o 4 por camada ) Los resultados sugieren que cuando la prevalencia dentro de la camada es ≥ 50%, la probabilidad de deteccion de ARN PRRSV en los fluidos de procesamiento seria mayor que la de los lechones individuales seleccionados al azar (es decir, ≥ 99%). Se realizaron comparaciones adicionales entre el enfoque de muestreo de fluidos de procesamiento y el esquema de monitoreo estandar de PRRSV usando 30 muestras de suero mediante simulacion por computadora (bootstrapping), dando como resultado una probabilidad general de deteccion de PRRSV del 100% cuando se usan fluidos de procesamiento vs 92.1% usando 30 muestras de suero . El Capitulo Tres tambien analizo el potencial de agrupacion de fluidos de procesamiento, demostrando que la deteccion de PRRSV era 100% alcanzable en el procesamiento de fluidos dentro de un escenario de baja prevalencia. La prueba de un grupo masivo con solo 8% de cerdos positivos para PRRSV (es decir, solo 67 cerdos viremicos de un total de 834 cerdos en el grupo) arrojo una fuerte respuesta positiva del ciclo de cuantificacion de RT-qPCR (Cq) (Cq = 22.0).Los dos objetivos principales del estudio descrito en el Capitulo Cuatro fueron: 1) evaluar el efecto de las condiciones previas a la prueba de procesamiento de muestras de fluidos en los resultados de las pruebas de RT-qPCR, como las temperaturas y el tiempo de almacenamiento de la muestra y los protocolos para la extraccion de acido nucleico y, 2) la adaptacion de un ensayo comercial de anticuerpos sericos PRRSV (ELISA) para la deteccion de tres isotipos diferentes de anticuerpos anti-PRRSV (Ab) (IgM, IgA e IgG) en fluidos de procesamiento y para establecer la muestra de prueba a positiva relacion de corte (S / P), es decir, el punto que mejor discrimina las muestras positivas y negativas. Los dos estudios dentro de este capitulo revelaron que, 1) el virus PRRS en el procesamiento de muestras de fluidos seria estable bajo refrigeracion por periodos de hasta 14 dias. Ademas, la exposicion prolongada a la habitacion y temperaturas mas altas tendrian, en consecuencia, un efecto perjudicial leve y fuerte sobre el ARN viral dentro de las muestras de fluido de procesamiento, por lo tanto, afectaria los resultados de las pruebas de RT-qPCR. Los resultados tampoco sugirieron ningun efecto en los resultados de las pruebas entre los cuatro kits comerciales diferentes de purificacion de ARN. 2) Los resultados obtenidos para el isotipo PRRSV IgG Ab mostraron una discriminacion perfecta entre muestras de fluido de procesamiento positivas y negativas utilizando un valor de corte de 0,5. Los resultados con el ELISA PRRS IgA e IgM para el procesamiento de fluidos mostraron una discriminacion de baja a pobre y, por lo tanto, necesitarian investigacion y optimizacion adicionales.El Capitulo Cinco modela el efecto de agrupar muestras de fluidos de procesamiento sobre la probabilidad de deteccion de ARN de PRRSV en un escenario de baja prevalencia y establece el limite para agrupar fluidos de procesamiento donde la probabilidad de deteccion de PRRSV no caeria por debajo del umbral del 95%. La deteccion de ARN de PRRSV en muestras de fluidos de procesamiento agrupados de camadas multiples (por ejemplo, 29 a 65), es factible cuando al menos un cerdo dentro de una camada dada en el grupo es positivo para PRRSV con un valor de RT-qPCR Cq  29. Por lo tanto, demostrando que los limites de deteccion para agrupar muestras de fluidos de procesamiento podrian depender de la magnitud de la viremia de los cerdos dentro de la muestra. Estos hallazgos podrian ser utiles para disenar protocolos de muestreo basados en fluidos de procesamiento precisos y confiables.
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