Effect of castration timing and weaning strategy on the taxonomic and functional profile of ruminal bacteria and archaea of beef calves.

BACKGROUND: Beef cattle experience several management challenges across their lifecycle. Castration and weaning, two major interventions in the early life of beef cattle, can have a substantial impact on animal performance. Despite the key role of the rumen microbiome on productive traits of beef cattle, the effect of castration timing and weaning strategy on this microbial community has not been formally described. We assessed the effect of four castration time windows (at birth, turnout, pre-weaning and weaning) and two weaning strategies (fence-line and truck transportation) on the rumen microbiome in a randomized controlled study with 32 male calves across 3 collection days (i.e., time points). Ruminal fluid samples were submitted to shotgun metagenomic sequencing and changes in the taxonomic (microbiota) and functional profile (metagenome) of the rumen microbiome were described. RESULTS: Using a comprehensive yet stringent taxonomic classification approach, we identified 10,238 unique taxa classified under 40 bacterial and 7 archaeal phyla across all samples. Castration timing had a limited long-term impact on the rumen microbiota and was not associated with changes in alpha and beta diversity. The interaction of collection day and weaning strategy was associated with changes in the rumen microbiota, which experienced a significant decrease in alpha diversity and shifts in beta diversity within 48 h post-weaning, especially in calves abruptly weaned by truck transportation. Calves weaned using a fence-line weaning strategy had lower relative abundance of Bacteroides, Lachnospira, Fibrobacter and Ruminococcus genera compared to calves weaned by truck transportation. Some genes involved in the hydrogenotrophic methanogenesis pathway (fwdB and fwdF) had higher relative abundance in fence-line-weaned calves post-weaning. The antimicrobial resistance gene tetW consistently represented more than 50% of the resistome across time, weaning and castration groups, without significant changes in relative abundance. CONCLUSIONS: Within the context of this study, castration timing had limited long-term effects on the rumen microbiota, while weaning strategy had short-term effects on the rumen microbiota and methane-associated metagenome, but not on the rumen resistome.

How Forces of a Complex Adaptive System Affect Ability to Control Bovine Respiratory Disease in Feeder Cattle.

This chapter provides an introductory look into the practical application of the principals of systems thinking as a methodology to gain deeper understanding of the nature of bovine respiratory disease (BRD) in current North American beef production models. The "limits to success" archetype is used to explore the dynamic relationship between technological BRD mitigation improvements and the resultant adaptive changes made by the system. The chapter concludes, by using the tragedy of the common archetype, with an investigation into how the common shared resource of antimicrobials can be damaged and depleted over time.

Current Reality of Beef Cattle Veterinary Practice in North America: A Systems Thinking Perspective.

Beef cattle veterinarians provide services to the increasingly complex beef industry system. Systems thinking offers pathways to better understand and communicate ranges of issues such as prevailing mental models, importance of match quality relative to clientele needs, and identification of leverage to better adapt and continually improve. Thinking in systems identifies and helps us to understand patterns or structures that are organized and interconnected that result in the outcomes observed and experienced in the practice of beef cattle veterinary medicine.

Predicting the time to detect moderately virulent African swine fever virus in finisher swine herds using a stochastic disease transmission model.

BACKGROUND: African swine fever (ASF) is a highly contagious and devastating pig disease that has caused extensive global economic losses. Understanding ASF virus (ASFV) transmission dynamics within a herd is necessary in order to prepare for and respond to an outbreak in the United States. Although the transmission parameters for the highly virulent ASF strains have been estimated in several articles, there are relatively few studies focused on moderately virulent strains. Using an approximate Bayesian computation algorithm in conjunction with Monte Carlo simulation, we have estimated the adequate contact rate for moderately virulent ASFV strains and determined the statistical distributions for the durations of mild and severe clinical signs using individual, pig-level data. A discrete individual based disease transmission model was then used to estimate the time to detect ASF infection based on increased mild clinical signs, severe clinical signs, or daily mortality. RESULTS: Our results indicate that it may take two weeks or longer to detect ASF in a finisher swine herd via mild clinical signs or increased mortality beyond levels expected in routine production. A key factor contributing to the extended time to detect ASF in a herd is the fairly long latently infected period for an individual pig (mean 4.5, 95% P.I., 2.4 - 7.2 days). CONCLUSION: These transmission model parameter estimates and estimated time to detection via clinical signs provide valuable information that can be used not only to support emergency preparedness but also to inform other simulation models of evaluating regional disease spread.

African swine fever detection and transmission estimates using homogeneous versus heterogeneous model formulation in stochastic simulations within pig premises.

Background: African swine fever (ASF) is one of the most important foreign animal diseases to the U.S. swine industry. Stakeholders in the swine production sector are on high alert as they witness the devastation of ongoing outbreaks in some of its most important trade partner countries. Efforts to improve preparedness for ASF outbreak management are proceeding in earnest and mathematical modeling is an integral part of these efforts. Aim: This study aimed to assess the impact on within-herd transmission dynamics of ASF when the models used to simulate transmission assume there is homogeneous mixing of animals within a barn. Methods: Barn-level heterogeneity was explicitly captured using a stochastic, individual pig-based, heterogeneous transmission model that considers three types of infection transmission, (1) within-pen via nose-to-nose contact; (2) between-pen via nose-to-nose contact with pigs in adjacent pens; and (3) both between- and within-pen via distance-independent mechanisms (e.g., via fomites). Predictions were compared between the heterogeneous and the homogeneous Gillespie models. Results: Results showed that the predicted mean number of infectious pigs at specific time points differed greatly between the homogeneous and heterogeneous models for scenarios with low levels of between-pen contacts via distance-independent pathways and the differences between the two model predictions were more pronounced for the slow contact rate scenario. The heterogeneous transmission model results also showed that it may take significantly longer to detect ASF, particularly in large barns when transmission predominantly occurs via nose-to-nose contact between pigs in adjacent pens. Conclusion: The findings emphasize the need for completing preliminary explorations when working with homogeneous mixing models to ascertain their suitability to predict disease outcomes.

The Risk of Highly Pathogenic Influenza A Virus Transmission to Turkey Hen Flocks Through Artificial Insemination.

Artificial insemination is a routine practice for turkeys that can introduce pathogens into breeder flocks in a variety of ways. In this manuscript, a risk analysis on the potential transmission of highly pathogenic avian influenza (HPAI) to naïve hens through artificial insemination is presented. A case of HPAI on a stud farm where the potential transmission of the virus to susceptible hens in the 2015 H5N2 HPAI outbreak in Minnesota is described along with documentation of known and potential transmission pathways from the case. The pathways by which artificial insemination might result in the spread of HPAI to susceptible hens were determined by considering which could result in the 1) entry of HPAI virus onto a premises through semen movement; and 2) exposure of susceptible hens to HPAI as a result of this movement. In the reported case, HPAI virus was detected in semen from infected toms, however, transmission of HPAI to naïve hens through semen is unclear since the in utero infectious dose is not known. This means that the early detection of infection might limit but not eliminate the risk of hen exposure. Because of the numerous potential pathways of spread and the close contact with the birds, it is highly likely that if semen from an HPAI-infected tom flock is used, there will be spread of the virus to naïve hens through insemination. If insemination occurs with semen from stud farms in an HPAI control area, receiving hen farms should have restricted movements to prevent outbreak spread in the event that they become infected.

Artículo regular­Riesgo de transmisión del virus de la influenza A altamente patógeno a parvadas de pavos hembras mediante inseminación artificial. La inseminación artificial es una práctica de rutina para los pavos que puede introducir patógenos en las parvadas de reproductores de diversas formas. En este manuscrito, se presenta un análisis de riesgo sobre la posible transmisión de la influenza aviar altamente patógena a gallinas susceptibles mediante inseminación artificial. Un caso de influenza aviar altamente patógena en una granja de machos sementales donde se describe la posible transmisión del virus a gallinas susceptibles en el brote de influenza aviar altamente patógena H5N2 del año 2015 en Minnesota, junto con la documentación de las vías de transmisión conocidas y potenciales del caso. Las vías por las cuales la inseminación artificial podría resultar en la propagación de la influenza aviar altamente patógena a las gallinas susceptibles se determinaron considerando cuáles podrían resultar en 1) la entrada del virus de la influenza aviar altamente patógena en una granja a través del movimiento del semen; y 2) exposición de gallinas susceptibles a la influenza aviar altamente patógena como resultado de este movimiento. Sin embargo, se demostró la detección del virus de la influenza aviar altamente patógena en el semen de machos infectados. Debido a que se desconoce la dosis infecciosa del virus de la influenza aviar administrada en el útero necesaria para transmitir la influenza aviar altamente patógena a las gallinas susceptibles, está claro que la detección de la infección no puede ser la única estrategia de contención. La detección temprana de la infección puede limitar, pero no eliminar, el riesgo de exposición de las gallinas. Debido a las numerosas vías potenciales de propagación y al estrecho contacto con las aves, es muy probable que si se usa semen de una parvada de machos infectados con influenza aviar de alta patogenicidad, se propague el virus a gallinas susceptibles a través de la inseminación. Si la inseminación ocurre con semen de granjas de sementales en un área de control de influenza aviar de alta patogenicidad, las granjas de gallinas receptoras deben tener movimientos restringidos para prevenir la propagación del brote en caso de que se infecten.

Development and Implementation of a National Center of Excellence in Dairy Production Medicine Education for Veterinary Students: Description of the Effort and Lessons Learned.

The need for consortial programs to provide advanced education in food animal veterinary production medicine has been recognized and lauded for nearly three decades. This article describes one effort to create a dairy production medicine curriculum funded by a United States Department of Agriculture (USDA) Higher Education Challenge Grant. This National Center of Excellence in Dairy Production Medicine Education for Veterinarians is housed at the Dairy Education Center of the University of Minnesota and the project was a collaboration of the University of Minnesota, the University of Illinois, the University of Georgia, and Kansas State University. The article reviews the need for innovative ways to educate students who will optimally serve the dairy industry, provides a broad overview of the process of developing and delivering the eight-week dairy production medicine curriculum, and describes the challenges faced and lessons learned as a result of offering such a program.

A Risk-Based Permitting Process for the Managed Movement of Animals and Products of Animal Origin as a Tool for Disease Management.

During a foreign animal disease (FAD) outbreak, in addition to detecting, controlling, containing, and eradicating the FAD, one of the goals of response in the United States (US), and many other countries, is to allow the managed movement of non-infected animals and non-contaminated animal products from within FAD control areas to facilitate continuity of business (COB). Permits issued by government authorities are the mechanism by which such managed movements are allowed in the US, resulting in permitted movements. The overall purpose of issuing permits during an outbreak is to minimize the risk of disease spread while still allowing movement of products or animals; thus, the risk associated with each permitted movement must be considered. Currently, there are federal guidelines for the various permit types and purposes. These guidelines state that permits should be "based on science and risk-based information." However, federal guidelines with specific procedures to determine risk are not readily available nor do they explicitly enumerate measures to assist regulatory authorities in using risk to guide decisions to grant permitted movement or deny a request to move. Although some pro-active risk assessments (RAs) have been conducted to determine risk of moving certain animals and their products, there will always be animal and product movements for which no pro-active RAs exist. We present here a process description of steps to conduct risk-based permitting with appropriate resource allocation to permitting by industry and regulatory authorities during an FAD outbreak.

Analysis of geographic location and pathways for influenza A virus infection of commercial upland game bird and conventional poultry farms in the United States of America.

BACKGROUND: Avian influenza (AI) is an infectious viral disease that affects several species and has zoonotic potential. Due to its associated health and economic repercussions, minimizing AI outbreaks is important. However, most control measures are generic and mostly target pathways important for the conventional poultry farms producing chickens, turkeys, and eggs and may not target other pathways that may be specific to the upland game bird sector. The goal of this study is to provide evidence to support the development of novel strategies for sector-specific AI control by comparing and contrasting practices and potential pathways for spread in upland game bird farms with those for conventional poultry farms in the United States. Farm practices and processes, seasonality of activities, geographic location and inter-farm distance were analyzed across the sectors. All the identified differences were framed and discussed in the context of their associated pathways for virus introduction into the farm and subsequent between-farm spread. RESULTS: Differences stemming from production systems and seasonality, inter-farm distance and farm densities were evident and these could influence both fomite-mediated and local-area spread risks. Upland game bird farms operate under a single, independent owner rather than being contracted with or owned by a company with other farms as is the case with conventional poultry. The seasonal marketing of upland game birds, largely driven by hunting seasons, implies that movements are seasonal and customer-vendor dynamics vary between industry groups. Farm location analysis revealed that, on average, an upland game bird premises was 15.42 km away from the nearest neighboring premises with birds compared to 3.74 km for turkey premises. Compared to turkey premises, the average poultry farm density in a radius of 10 km of an upland game bird premises was less than a half, and turkey premises were 3.8 times (43.5% compared with 11.5%) more likely to fall within a control area during the 2015 Minnesota outbreak. CONCLUSIONS: We conclude that the existing differences in the seasonality of production, isolated geographic location and epidemiological seclusion of farms influence AI spread dynamics and therefore disease control measures should be informed by these and other factors to achieve success.

Mortality-Based Triggers and Premovement Testing Protocols for Detection of Highly Pathogenic Avian Influenza Virus Infection in Commercial Upland Game Birds.

Outbreaks involving avian influenza viruses are often devastating to the poultry industry economically and otherwise. Disease surveillance is critically important because it facilitates timely detection and generates confidence that infected birds are not moved during business continuity intended to mitigate associated economic losses. The possibility of using an abnormal increase in daily mortality to levels that exceed predetermined thresholds as a trigger to initiate further diagnostic investigations for highly pathogenic avian influenza (HPAI) virus infection in the flock is explored. The range of optimal mortality thresholds varies by bird species, trigger type, and mortality thresholds, and these should be considered when assessing sector-specific triggers. The study uses purposefully collected data and data from the literature to determine optimal mortality triggers for HPAI detection in commercial upland game bird flocks. Three trigger types were assessed for the ability to detect rapidly both HPAI (on the basis of disease-induced and normal mortality data) and false alarm rate (on the basis of normal mortality data); namely, 1) exceeding a set absolute threshold on one day, 2) exceeding a set absolute threshold on two consecutive days, or 3) exceeding a multiple of a seven-day moving average. The likelihood of disease detection using some of these triggers together with premovement real-time reverse transcription PCR (rRT-PCR) testing was examined. Results indicate that the performance of the two consecutive days trigger had the best metrics (i.e., rapid detection with few false alarms) in the trade-off analysis. The collected normal mortality data was zero on 66% of all days recorded, with an overall mean of 0.6 dead birds per day. In the surveillance scenario analyses, combining the default protocol that relied only on active surveillance (i.e., premovement testing of oropharyngeal swab samples from dead birds by rRT-PCR) together with either of the mortality-based triggers improved detection rates on all days postexposure before scheduled movement. For exposures occurring within 8 days of movement, the protocol that combined the default with single-day triggers had slightly more detections than that with two consecutive days triggers. However, all assessed protocol combinations were able to detect all infections that occurred more than 10 days before scheduled movement. These findings can inform risk-based decisions pertaining to continuity of business in the commercial upland game bird industry.

Activadores basados en la mortalidad y protocolos de pruebas de premovimiento para la detección de la infección del virus de influenza aviar altamente patógena en aves de caza de tierras altas comerciales Los brotes que involucran virus de influenza aviar a menudo son económicamente devastadores para la industria avícola. La vigilancia de enfermedades es de importancia crítica porque facilita la detección oportuna y genera confianza en que las aves infectadas no serán movilizadas para continuar con la operación de las industrias avícolas para mitigar las pérdidas económicas asociadas. Se explora la posibilidad de utilizar un aumento anormal en la mortalidad diaria a niveles que excedan umbrales predeterminados como un desencadenante para iniciar investigaciones de diagnóstico para la infección del virus de la influenza aviar altamente patógena en la parvada. El rango de umbrales de mortalidad óptimos varían según la especie de ave, el tipo de activador y los umbrales de mortalidad y estos deben considerarse al evaluar los activadores específicos del sector. El estudio utiliza datos recopilados de manera planeada y datos de la literatura para determinar los desencadenantes de mortalidad óptimos para la detección de la influenza aviar altamente patógena en las parvadas comerciales de aves de caza de tierras altas. Se evaluaron tres activadores de acuerdo a su capacidad de detectar rápidamente influenza aviar altamente patógena (en función de los datos de mortalidad normal e inducida por la enfermedad) y la tasa de falsa alarma (en función de los datos de mortalidad normal); como son, 1) que se exceda un umbral absoluto establecido en un día, 2) que se exceda un umbral absoluto establecido en dos días consecutivos, o 3) que excede un múltiplo de un promedio móvil de siete días. Se examinó la probabilidad de detección de la enfermedad utilizando algunos de estos desencadenantes junto con la prueba de transcripción reversa y PCR en tiempo real (rRT-PCR). Los resultados indicaron que el rendimiento del disparador de dos días consecutivos tuvo los mejores resultados (es decir, detección rápida con pocas falsas alarmas) en el análisis costo-beneficio. Los datos de mortalidad normal recopilados fueron cero en el 66% de todos los días registrados, con una media general de 0.6 aves muertas por día. En los análisis de escenarios de vigilancia, la combinación del protocolo predeterminado que se basó únicamente en la vigilancia activa (por ejemplo pruebas antes de movilizaciones con muestras de hisopos orofaríngeos por rRT-PCR de aves muertas) a la par con cualquiera de los desencadenantes basados en la mortalidad mejoraron las tasas de detección en todos los días posteriores a la exposición antes del movimiento programado. Para las exposiciones que ocurrieron dentro de los ocho días de movimiento, el protocolo que combinó el valor predeterminado con los activadores de un solo día tuvo un poco más de detecciones que el de los activadores de dos días consecutivos. Sin embargo, todas las combinaciones de protocolos evaluadas pudieron detectar todas las infecciones que ocurrieron por más de 10 días antes del movimiento programado. Estos hallazgos pueden proveer información para la toma de decisiones basadas en el riesgo relacionadas con la continuidad de operaciones en la industria comercial de aves de caza de tierras altas.

Evaluating the Effect of the Within-Flock Disease Transmission Rate on Premovement Active Surveillance in Low Pathogenicity Avian Influenza-Infected Flocks.

Premovement active surveillance for low pathogenicity avian influenza (LPAI) may be a useful risk management tool for producers during high-risk periods, such as during an LPAI outbreak, or in areas where there is a recognized high risk for LPAI spread. The effectiveness of three active-surveillance protocols in mitigating LPAI spread risk related to the movement of spent broiler breeders to processing was evaluated in this study. Each protocol differed in the amount of real-time reverse transcription polymerase chain reaction (RRT-PCR) and serology testing conducted. The protocols were evaluated with the use of disease transmission and active surveillance simulation models parametrized specifically for broiler breeders to estimate the probability of detecting a current or past infection and the mean proportion of infectious birds at the time of sampling in houses where the infection remains undetected at the time of movement after exposure to the virus. The two values were estimated considering flock infection for 1-28 days prior to the day of scheduled movement. A distribution for the adequate contact rate, a parameter that controls the rate of within-house spread in the disease transmission model, was estimated for this study by a novel forward simulation approach with the use of serology data from three LPAI-infected broiler breeder flocks in the United States. The estimated distribution suggests that the lower contact-rate estimates from previously published studies were not a good fit for the serology results observed in these U.S. flocks, though considerable uncertainty remains in the parameter estimate. The results for the probability of detection and mean proportion of infectious, undetected birds suggest that RRT-PCR testing is most beneficial during the early stages of infection postexposure, and serology testing is most beneficial during the later stages of infection, results that are expected to hold for flocks outside the United States as well. Thus, protocols that combine RRT-PCR and serology testing can offer a more balanced approach with good performance over the disease course in a flock.

Evaluación del efecto de la tasa de transmisión dentro de la parvada en la vigilancia activa previa al movimiento de parvadas infectadas por influenza aviar de baja patogenicidad. La vigilancia activa para la influenza aviar de baja patogenicidad (LPAI) previa al movimiento puede ser una herramienta útil en el manejo de riesgos para los productores durante períodos de alto riesgo, como durante un brote de influenza aviar de baja patogenicidad o en áreas donde se reconoce que existe un alto riesgo de propagación de esta enfermedad. En este estudio, se evaluó la efectividad de tres protocolos de vigilancia activa para mitigar el riesgo de propagación de la influenza aviar de baja patogenicidad relacionado con el movimiento de los reproductores pesados de desecho a la planta de procesamiento. Los protocolos diferían en la cantidad de muestras procesadas por la transcriptasa reversa y reacción en cadena de la polimerasa en tiempo real (rRT-PCR) y por las pruebas serológicas realizadas. Los protocolos se evaluaron utilizando modelos de simulación de vigilancia activa y transmisión de la enfermedad con parámetros específicamente para reproductores pesados, para estimar la probabilidad de detectar una infección actual o pasada y la proporción media de aves con infección activa al momento del muestreo en casetas donde la infección permanecía sin detectar al momento del movimiento después de la exposición al virus. Los dos valores se estimaron considerando la infección de la parvada de uno a 28 días antes de la fecha programada para el movimiento. Una distribución para la tasa de contacto adecuada, un parámetro que controla la tasa de propagación dentro de la caseta en el modelo de transmisión de la enfermedad, se estimó para este estudio mediante un novedoso enfoque de simulación directa utilizando datos serológicos de tres parvadas reproductores pesados infectados con influenza aviar de baja patogenicidad en los Estados Unidos. La distribución estimada sugiere que las estimaciones de la tasa de contacto más baja obtenida de los estudios publicados previamente no fueron una buena opción para los resultados serológicos observados en estas parvadas en los Estados Unidos, aunque sigue existiendo una gran incertidumbre en la estimación del parámetro. Los resultados de la probabilidad de detección y la proporción media de aves con infección no detectadas sugieren que la prueba rRT-PCR es más beneficiosa durante las primeras etapas de la infección después de la exposición, mientras que la serología es más beneficiosa durante las últimas etapas de la infección, resultados que se espera apliquen también para parvadas fuera de los Estados Unidos. Por lo tanto, los protocolos que combinan rRT-PCR y las pruebas de serología pueden ofrecer un enfoque más equilibrado con un buen rendimiento durante el curso de la enfermedad en una parvada.

Maturational Changes in Human Dorsal and Ventral Visual Networks.

Developmental neuroimaging studies report the emergence of increasingly diverse cognitive functions as closely entangled with a rise-fall modulation of cortical thickness (CTh), structural cortical and white-matter connectivity, and a time-course for the experience-dependent selective elimination of the overproduced synapses. We examine which of two visual processing networks, the dorsal (DVN; prefrontal, parietal nodes) or ventral (VVN; frontal-temporal, fusiform nodes) matures first, thus leading the neuro-cognitive developmental trajectory. Three age-dependent measures are reported: (i) the CTh at network nodes; (ii) the matrix of intra-network structural connectivity (edges); and (iii) the proficiency in network-related neuropsychological tests. Typically developing children (age ~6 years), adolescents (~11 years), and adults (~21 years) were tested using multiple-acquisition structural T1-weighted magnetic resonance imaging (MRI) and neuropsychology. MRI images reconstructed into a gray/white/pial matter boundary model were used for CTh evaluation. No significant group differences in CTh and in the matrix of edges were found for DVN (except for the left prefrontal), but a significantly thicker cortex in children for VVN with reduced prefrontal ventral-fusiform connectivity and with an abundance of connections in adolescents. The higher performance in children on tests related to DVN corroborates the age-dependent MRI structural connectivity findings. The current findings are consistent with an earlier maturational course of DVN.

Modeling the Transmission of Foot and Mouth Disease to Inform Transportation of Infected Carcasses to a Disposal Site During an Outbreak Event.

In the event of a Food and Mouth Disease (FMD) outbreak in the United States, an infected livestock premises is likely to result in a high number of carcasses (swine and/or cattle) as a result of depopulation. If relocating infected carcasses to an off-site disposal site is allowed, the virus may have increased opportunity to spread to uninfected premises and result in exposure of susceptible livestock. A stochastic within-herd disease spread model was used to predict the time to detect the disease by observation of clinical signs within the herd, and the number of animals in different disease stages over time. Expert opinion was elicited to estimate depopulation parameters in various scenarios. Disease detection was assumed when 5% of the population showed clinical signs by direct observation. Time to detection (5 and 95th percentile values) was estimated for all swine farm sizes (500-10,000 head) ranged from 102 to 282 h, from 42 to 216 h for all dairy cattle premises sizes (100-2,000 head) and from 66 to 240 h for all beef cattle premises sizes (5,000-50,000 head). Total time from infection to beginning depopulation (including disease detection and confirmation) for the first FMD infected case was estimated between 8.5-14.3 days for swine, 6-12.8 days for dairy or beef cattle premises. Total time estimated for subsequent FMD cases was between 6.8-12.3 days for swine, 4.3-10.8 days for dairy and 4.5-10.5 days for beef cattle premises. On an average sized operation, a sizable proportion of animals in the herd (34-56% of swine, 48-60% of dairy cattle, and 47-60% of beef cattle for the first case and 49-60% of swine, 55-60% of dairy cattle, 56-59% of beef cattle for subsequent cases) would be viremic at the time of beginning depopulation. A very small fraction of body fluids from the carcasses (i.e., 1 mL) would contain virus that greatly exceeds the minimum infectious dose by oral (4-7x) or inhalation (7-13x) route for pigs and cattle.

Planning "Plan B": The Case of Moving Cattle From an Infected Feedlot Premises During a Hypothetical Widespread FMD Outbreak in the United States.

In the event of a foot-and-mouth disease (FMD) outbreak in the United States, "stamping out" FMD infected premises has been proposed as the method of choice for the control of outbreaks. However, if a widespread, catastrophic FMD outbreak in the U.S. were to occur, alternative solutions to stamping out may be required, particularly for large feedlots with over 10,000 cattle. Such strategies include moving cattle from infected or not known to be infected operations to slaughter facilities either with or without prior implementation of vaccination. To understand the risk of these strategies, it is important to estimate levels of herd viremia. Multiple factors must be considered when determining risk and feasibility of moving cattle from a feedlot to a slaughter facility during an FMD outbreak. In addition to modeling within-herd disease spread to estimate prevalence of viremic animals, we explore potential pathways for viral spread associated with the movement of asymptomatic beef cattle (either pre-clinical or recovered) from an infected feedlot premises to offsite harvest facilities. This analysis was proactive in nature, however evaluation of the likelihood of disease spread relative to disease (infection) phase, time of movement, and vaccination status are all factors which should be considered in managing and containing a large-scale FMD outbreak in the United States.

Avian Influenza in the U.S. Commercial Upland Game Bird Industry: An Analysis of Selected Practices as Potential Exposure Pathways and Surveillance System Data Reporting.

Producing a smaller yield of higher-value birds compared to conventional poultry production, the U.S. commercial upland game bird industry deals primarily in the sale of live birds for recreational hunting. In this study, our aims were to gain insights into the occurrence of avian influenza (AI) in the U.S. commercial upland game bird industry in comparison to other poultry sectors, to identify the presence of the specific AI risk factors in the practices of raising ducks on site and having connections to live bird markets (LBMs), and to assess how AI surveillance systems may have played a role in the reporting of the presence of exposure pathway-related information. We found that 23 AI epizootics involving upland game bird premises were reported, compared to 485 epizootics in the other poultry industries, and 86% of epizootics involving upland game birds were limited to only one premises. Regarding specific AI risk factors, 70% of upland game bird epizootics involved one of the two examined practices. In assessing the impact of surveillance systems, data framed around the implementation of surveillance systems revealed that the introduction of active surveillance coincided with the more thorough reporting of both the raising of ducks on site and premises having connections to LBMs. Our results suggest the need for more thorough data collection during epizootics and the need to assess additional exposure pathways specific to the commercial raise-for-release upland game bird industry.

Preparing for a Foreign Animal Disease Outbreak Using a Novel Tabletop Exercise.

IntroductionForeign animal disease (FAD) outbreaks can have devastating impacts, but they occur infrequently in any specific sector anywhere in the United States (US). Training to proactively discuss implementation of control and prevention strategies are beneficial in that they provide stakeholders with the practical information and educational experience they will need to respond effectively to an FAD. Such proactive approaches are the mission of the Secure Food System (SFS; University of Minnesota; St. Paul, Minnesota USA). METHODS: The SFS exercises were designed as educational activities based on avian influenza (AI) outbreaks in commercial poultry scenarios. These scenarios were created by subject matter experts and were based on epidemiology reports, risk pathway analyses, local industry practices, and site-specific circumstances. Target audiences of an exercise were the groups involved in FAD control: animal agriculture industry members; animal health regulators; and diagnosticians. Groups of industry participants seated together at tables represented fictional poultry premises and were guided by a moderator to respond to an on-farm situation within a simulated outbreak. The impact of SFS exercises was evaluated through interviews with randomized industry participants and selected table moderators. Descriptive statistics and qualitative analyses were performed on interview feedback. RESULTS: Eleven SFS exercises occurred from December 2016 through October 2017 in multiple regions of the US. Exercises were conducted as company-wide, state-wide, or regional trainings. Nine were based on highly pathogenic avian influenza (HPAI) outbreaks and two focused on outbreaks of co-circulating HPAI and low pathogenicity avian influenza (LPAI). Poultry industry participants interviewed generally found attending an SFS exercise to be useful. The most commonly identified benefits of participation were its value to people without prior outbreak experience and knowledge gained about Continuity of Business (COB)-permitted movement. After completing an exercise, most participants evaluated their preparedness to respond to an outbreak as somewhat to very ready, and more than one-half reported their respective company or farms had discussions or changed actions due to participation. CONCLUSION: Evaluation feedback suggests the SFS exercises were an effective training method to supplement preparedness efforts for an AI outbreak. The concept of using multi-faceted scenarios and multiple education strategies during a tabletop exercise may be translatable to other emergency preparedness needs. LinskensEJ, NeuAE, WalzEJ, St. CharlesKM, CulhaneMR, SsematimbaA, GoldsmithTJ, HalvorsonDA, CardonaCJ. Preparing for a foreign animal disease outbreak using a novel tabletop exercise. Prehosp Disaster Med. 2018;33(6):640-646.

Establishing Monitored Premises Status for Continuity of Business Permits During an HPAI Outbreak.

Recent experiences with avian influenza outbreaks in poultry in the United States have tested biosecurity protocols and outbreak management strategies. During an outbreak, regulatory officials managing the emergency response need to make timely decisions in order to achieve disease control and eradication goals while simultaneously decreasing the unintended consequences of the response. To move susceptible animals or animal products out of a disease Control Area via a secure food supply continuity of business (COB) permit without the risk of expanding a disease outbreak, premises must be designated as Monitored Premises (MP) by regulatory officials. The experience of and lessons learned from the 2014 to 2015 highly pathogenic avian influenza (HPAI) outbreak have resulted in defined criteria necessary to establish MP status during an HPAI outbreak and highlighted the need for a clear method to determine that those criteria have been met. Establishing MP status is different from an epidemiologic investigation, though they both require analyses of how avian influenza virus may enter poultry premises and can take significant staff time. MP status of premises seeking to move animals or animal products must be continuously re-evaluated as Infected Premises status, and resulting epidemiologic contacts, can rapidly change during an outbreak. We present here a questionnaire to establish MP status, designed to be initially completed by industry representatives in an attempt to streamline processes and conserve resources. During an outbreak, the MP status questionnaire is an essential risk-based management tool used to establish premises status, as part of operationalizing permitted movement to support COB.

Environmental Sampling Survey of H5N2 Highly Pathogenic Avian Influenza-Infected Layer Chicken Farms in Minnesota and Iowa.

Respiratory secretions, feces, feathers, and eggs of avian influenza-infected hens provide ample sources of virus which heavily contaminate barn and farm environments during a disease outbreak. Environmental sampling surveys were conducted in the Midwestern United States on affected farms during the 2015 H5N2 highly pathogenic avian influenza (HPAI) outbreak to assess the degree of viral contamination. A total of 930 samples were obtained from various sites inside and outside layer barns housing infected birds and tested with real-time reverse transcriptase PCR. The distribution and load of viral RNA in barns in which most birds were dead at the onset of depopulation efforts (high-mortality barns) were compared with those of barns in which birds were euthanatized before excess mortality occurred (normal-mortality barns). A statistically significant difference was seen between cycle threshold (Ct) values for samples taken of fans, feed troughs, barn floors, barn walls, cages, manure-associated locations, barn doors, egg belts, and the exterior of high-mortality vs. normal-mortality barns. In high-mortality barns, sample sites were found to be the most to least contaminated in the following order: cages, manure-associated locations, barn floors, egg belts, feed troughs, barn doors, barn walls, fans, exterior, and egg processing. Significant changes in Ct values over time following HPAI detection in a barn and depopulation of birds on an infected farm were observed for the manure-associated, barn floor, barn wall, and fan sampling sites. These results show that high mortality in a flock as a result of HPAI will increase contamination of the farm environment. The results also suggest optimal sampling locations for detection of virus; however, the persistence of RNA on highmortality farms may delay the determination that adequate sanitization has been performed for restocking to take place.

Estudios de muestreo ambiental de granjas de gallinas de postura infectadas con influenza aviar altamente patógena H5N2 en Minnesota y Iowa. Las secreciones respiratorias, las heces, las plumas y huevos de gallinas infectadas con influenza aviar brindan amplias fuentes de virus para contaminar las casetas y el ambiente de la granja durante un brote de la enfermedad. Se realizaron estudios de muestreo ambiental en el medio oeste de los Estados Unidos en granjas afectadas durante el brote de influenza aviar altamente patógena H5N2 del año 2015 para evaluar el grado de contaminación viral. Se obtuvieron un total de 930 muestras de varios sitios dentro y fuera de las casetas de gallinas de postura que albergaron aves infectadas y se analizaron mediante pruebas de transcripción reversa y PCR en tiempo real. La distribución y la carga de ARN viral en casetas en las que la mayoría de las aves estaban muertas al inicio de los esfuerzos de despoblación (casetas de alta mortalidad) se compararon con los de las casetas en los que las aves se sacrificaron antes de que se produjera un exceso de mortalidad (casetas de mortalidad normal). Se observó una diferencia estadísticamente significativa entre los valores de ciclos umbrales (Ct) para muestras tomadas de ventiladores, comederos, pisos de casetas, paredes de casetas, jaulas, sitios asociados con gallinaza, puertas de casetas, bandas transportadoras de huevos y el exterior de las casetas con alta mortalidad en comparación con las casetas con mortalidad normal. En las casetas de alta mortalidad, se encontró que los sitios donde se recolectaron muestras presentaron contaminación de mayor grado a menor grado en el siguiente orden: jaulas, lugares asociados con gallinaza, pisos de casetas, bandas de huevos, comederos, puertas de casetas, paredes de casetas, ventiladores, exteriores y locales para el tratamiento del huevo. Se observaron cambios significativos en los valores de Ct a lo largo del tiempo después de la detección de la influenza aviar de alta patogenicidad en una caseta y de la despoblación de aves en una granja infectada en los sitios de muestreo asociados con gallinaza, en el piso de la caseta, en las paredes y en los ventiladores. Estos resultados muestran que la alta mortalidad en una parvada como resultado de influenza aviar de alta patogenicidad aumentará la contaminación del entorno de la granja. Los resultados también sugieren ubicaciones de muestreo óptimas para la detección de virus; sin embargo, la persistencia del ARN en las granjas de alta mortalidad puede retrasar la determinación de que se haya realizado un saneamiento adecuado para que se lleve a cabo la repoblación.

A Simulation-Based Evaluation of Premovement Active Surveillance Protocol Options for the Managed Movement of Turkeys to Slaughter During an Outbreak of Highly Pathogenic Avian Influenza in the United States.

Risk management decisions associated with live poultry movement during a highly pathogenic avian influenza (HPAI) outbreak should be carefully considered. Live turkey movements may pose a risk for disease spread. On the other hand, interruptions in scheduled movements can disrupt business continuity. The Secure Turkey Supply (STS) Plan was developed through an industry-government-academic collaboration to address business continuity concerns that might arise during a HPAI outbreak. STS stakeholders proposed outbreak response measure options that were evaluated through risk assessment. The developed approach relies on 1) diagnostic testing of two pooled samples of swabs taken from dead turkeys immediately before movement via the influenza A matrix gene real-time reverse transcriptase polymerase chain reaction (rRT-PCR) test; 2) enhanced biosecurity measures in combination with a premovement isolation period (PMIP), restricting movement onto the premises for a few days before movement to slaughter; and 3) incorporation of a distance factor from known infected flocks such that exposure via local area spread is unlikely. Daily exposure likelihood estimates from spatial kernels from past HPAI outbreaks were coupled with simulation models of disease spread and active surveillance to evaluate active surveillance protocol options that differ with respect to the number of swabs per pooled sample and the timing of the tests in relation to movement. Simulation model results indicate that active surveillance testing, in combination with strict biosecurity, substantially increased HPAI virus detection probability. When distance from a known infected flock was considered, the overall combined likelihood of moving an infected, undetected turkey flock to slaughter was predicted to be lower at 3 and 5 km. The analysis of different active surveillance protocol options is designed to incorporate flexibility into HPAI emergency response plans.