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In March 2024, highly pathogenic avian influenza A(H5N1) virus, clade 2.3.4.4b, was detected in dairy cows in the United States, and at the same time in resident cats on affected farms. To help guide sample collection and diagnosis in cats, here we report the distribution of lesions and detection of H5N1 clade 2.3.4.4b influenza A virus (IAV) infection by PCR, immunohistochemistry (IHC), and serology in samples from 4 deceased and 2 living cats from 3 separate affected dairy farms. Although gross lesions were not diagnostic, histologically, all 4 deceased cats had nonsuppurative and necrotizing encephalitis and subtle interstitial pneumonia, and some also had significant myocarditis (3 of 4), chorioretinitis (2 of 4), and sialadenitis (1 of 2). The virus was detected by IHC in the aforementioned tissues, and by PCR in each brain (Ct = 9.9-25.1), lung (17.4-32.7), oropharyngeal swab (28.3-30.5), urine (30.3-34.4), and nasal swab (33.5-34.1) collected postmortem; fecal swabs were PCR-negative. In the antemortem samples, the virus was detected by PCR in the oropharyngeal swabs (34.1-36.1), whole-blood samples (30.8-36.6), and one serum sample (31.7). Seroconversion was detected in one cat. Our results support histologic evaluation of brain, lung, eyes, and heart, and PCR testing of brain and lung for postmortem diagnosis, and show that oropharyngeal swabs, urine, serum, and whole blood are suitable samples for antemortem detection of IAV infection in clinically affected cats., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Veterinary diagnostic laboratories provide a vast catalog of tests for infectious agents and often have multiple tests and testing modalities for individual pathogens. Understanding which test to select, which sample type is best, and which animal to sample in a population are critical factors for drawing appropriate conclusions and diagnosing a disease. Each diagnostic test has its inherent diagnostic sensitivity and specificity, and, in many situations, multiple tests may be required for proper interpretation. When multiple tests are needed in a large population (eg, animal shelters, farmed animals, and breeding colonies), the cost of diagnostic testing becomes an increasing concern, and knowing when and how to use aggregate or composite samples is critical. A clinical examination is the first and arguably most important diagnostic procedure providing the framework for laboratory test selection. This yields not only a differential diagnosis but an expected stage of disease, which is necessary for determining the most appropriate laboratory tests and how they should be interpreted. This review will discuss the diagnostic process, strengths and limitations of commonly requested tests at a diagnostic laboratory (eg, histopathology, microbial culture, PCR, and ELISA), common sources of error in interpretation, the impact of pooling samples on different tests, and ways to help strengthen conclusions made from diagnostic test data.

In March 2024, the emergence of highly pathogenic avian influenza (HPAI) A (H5N1) infections in dairy cattle was detected in the United Sates for the first time. We genetically characterize HPAI viruses from dairy cattle showing an abrupt drop in milk production, as well as from two cats, six wild birds, and one skunk. They share nearly identical genome sequences, forming a new genotype B3.13 within the 2.3.4.4b clade. B3.13 viruses underwent two reassortment events since 2023 and exhibit critical mutations in HA, M1, and NS genes but lack critical mutations in PB2 and PB1 genes, which enhance virulence or adaptation to mammals. The PB2 E627 K mutation in a human case associated with cattle underscores the potential for rapid evolution post infection, highlighting the need for continued surveillance to monitor public health threats.

Streptococcus suis negatively impacts swine health, posing diagnostic and preventative challenges. S. suis can induce disease and also quietly reside on mucosal surfaces. The limited use of diagnostic tools to identify disease-associated strains and rule out differential diagnoses, alongside the complex ecology of S. suis , poses significant challenges in comprehending this important pathogen and defining pathotypes. This study evaluated 2,379 S . suis central nervous system (CNS) isolates from diagnostic submissions between 2015 and 2019. Isolates originating from submissions with histologic evidence of CNS infection ( n = 1,032) were further characterized by standard and advanced diagnostic techniques. We identified 29 S . suis serotypes and 4 reclassified serotypes as putative causes of CNS disease. Among these, serotypes 1 and 7 emerged as the predominant putative causes of CNS infection (32% of submissions). Furthermore, 51 sequence types (STs), of which 15 were novel, were detected with ST1 predominating. Through whole-genome sequencing of 145 isolates, we observed that five commonly used virulence-associated genes (VAGs; epf , mrp , sly , ofs , and srtF ) were not present in most disease-associated isolates, and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) yielded false-positive results in 7% of isolates. These data indicate that (i) clinical signs and site of isolation alone are insufficient for defining a pathotype, (ii) S. suis serotypes and STs associated with CNS infection are more diverse than previously reported, (iii) MALDI-TOF MS may need to be supplemented with additional diagnostic tools for precise S. suis identification, and (iv) VAGs remain an unreliable means for identifying isolates associated with CNS disease.IMPORTANCE Streptococcus suis is an important and complex systemic bacterial pathogen of swine. Characterization of S. suis strains originating from pigs with histologic confirmation of neurologic disease is limited. Review of swine diagnostic submissions revealed that fewer than half of cases from which S. suis was isolated from the brain had histologic evidence of neurologic disease. This finding demonstrates that clinical signs and site of isolation alone are not sufficient for identifying a neurologic disease-associated strain. Characterization of strains originating from cases with evidence of disease using classic and advanced diagnostic techniques revealed that neurologic disease-associated strains are diverse and commonly lack genes previously associated with virulence., Competing Interests: The authors declare no conflict of interest.

In March 2024, the US Department of Agriculture's Animal and Plant Health Inspection Service reported detection of highly pathogenic avian influenza (HPAI) A(H5N1) virus in dairy cattle in the United States for the first time. One factor that determines susceptibility to HPAI H5N1 infection is the presence of specific virus receptors on host cells; however, little is known about the distribution of the sialic acid (SA) receptors in dairy cattle, particularly in mammary glands. We compared the distribution of SA receptors in the respiratory tract and mammary gland of dairy cattle naturally infected with HPAI H5N1. The respiratory and mammary glands of HPAI H5N1-infected dairy cattle are rich in SA, particularly avian influenza virus-specific SA α2,3-gal. Mammary gland tissues co-stained with sialic acids and influenza A virus nucleoprotein showed predominant co-localization with the virus and SA α2,3-gal. HPAI H5N1 exhibited epitheliotropism within the mammary gland, and we observed rare immunolabeling within macrophages.

We report highly pathogenic avian influenza A(H5N1) virus in dairy cattle and cats in Kansas and Texas, United States, which reflects the continued spread of clade 2.3.4.4b viruses that entered the country in late 2021. Infected cattle experienced nonspecific illness, reduced feed intake and rumination, and an abrupt drop in milk production, but fatal systemic influenza infection developed in domestic cats fed raw (unpasteurized) colostrum and milk from affected cows. Cow-to-cow transmission appears to have occurred because infections were observed in cattle on Michigan, Idaho, and Ohio farms where avian influenza virus-infected cows were transported. Although the US Food and Drug Administration has indicated the commercial milk supply remains safe, the detection of influenza virus in unpasteurized bovine milk is a concern because of potential cross-species transmission. Continued surveillance of highly pathogenic avian influenza viruses in domestic production animals is needed to prevent cross-species and mammal-to-mammal transmission.

Swine are increasingly studied as animal models of human disease. The anatomy, size, longevity, physiology, immune system, and metabolism of swine are more like humans than traditional rodent models. In addition, the size of swine is preferred for surgical placement and testing of medical devices destined for humans. These features make swine useful for biomedical, pharmacological, and toxicological research. With recent advances in gene-editing technologies, genetic modifications can readily and efficiently be made in swine to study genetic disorders. In addition, gene-edited swine tissues are necessary for studies testing and validating xenotransplantation into humans to meet the critical shortfall of viable organs versus need. Underlying all of these biomedical applications, the knowledge of husbandry, background diseases and lesions, and biosecurity needs are important for productive, efficient, and reproducible research when using swine as a human disease model for basic research, preclinical testing, and translational studies., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Swine dysentery, caused by Brachyspira hyodysenteriae and the newly recognized Brachyspira hampsonii in grower-finisher pigs, is a substantial economic burden in many swine-rearing countries. Antimicrobial therapy is the only commercially available measure to control and prevent Brachyspira -related colitis. However, data on antimicrobial susceptibility trends and genetic diversity of Brachyspira species from North America is limited. We evaluated the antimicrobial susceptibility profiles of U.S. Brachyspira isolates recovered between 2013 and 2022 to tiamulin, tylvalosin, lincomycin, doxycycline, bacitracin, and tylosin. In addition, we performed multilocus sequence typing (MLST) on 64 B. hyodysenteriae isolates. Overall, no distinct alterations in the susceptibility patterns over time were observed among Brachyspira species. However, resistance to the commonly used antimicrobials was seen sporadically with a higher resistance frequency to tylosin compared to other tested drugs. B. hampsonii was more susceptible to the tested drugs than B. hyodysenteriae and B. pilosicoli . MLST revealed 16 different sequence types (STs) among the 64 B. hyodysenteriae isolates tested, of which 5 STs were previously known, whereas 11 were novel. Most isolates belonged to the known STs: ST93 ( n  = 32) and ST107 ( n  = 13). Our findings indicate an overall low prevalence of resistance to clinically important antimicrobials other than tylosin and bacitracin, and high genetic diversity among the clinical Brachyspira isolates from pigs in the United States during the past decade. Further molecular, epidemiologic, and surveillance studies are needed to better understand the infection dynamics of Brachyspira on swine farms and to help develop effective control measures., Competing Interests: Declaration of conflicting interestsThe authors declared no conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Accurate measurement of disease associated with endemic bacterial agents in pig populations is challenging due to their commensal ecology, the lack of disease-specific antemortem diagnostic tests, and the polymicrobial nature of swine diagnostic cases. The main objective of this retrospective study was to estimate temporal patterns of agent detection and disease diagnosis for five endemic bacteria that can cause systemic disease in porcine tissue specimens submitted to the Iowa State University Veterinary Diagnostic Laboratory (ISU VDL) from 2017 to 2022. The study also explored the diagnostic value of specific tissue specimens for disease diagnosis, estimated the frequency of polymicrobial diagnosis, and evaluated the association between phase of pig production and disease diagnosis., Results: S. suis and G. parasuis bronchopneumonia increased on average 6 and 4.3%, while S. suis endocarditis increased by 23% per year, respectively. M. hyorhinis and A. suis associated serositis increased yearly by 4.2 and 12.8%, respectively. A significant upward trend in M. hyorhinis arthritis cases was also observed. In contrast, M. hyosynoviae arthritis cases decreased by 33% average/year. Investigation into the diagnostic value of tissues showed that lungs were the most frequently submitted sample, However, the use of lung for systemic disease diagnosis requires caution due to the commensal nature of these agents in the respiratory system, compared to systemic sites that diagnosticians typically target. This study also explored associations between phase of production and specific diseases caused by each agent, showcasing the role of S. suis arthritis in suckling pigs, meningitis in early nursery and endocarditis in growing pigs, and the role of G. parasuis, A. suis, M. hyorhinis and M. hyosynoviae disease mainly in post-weaning phases. Finally, this study highlighted the high frequency of co-detection and -disease diagnosis with other infectious etiologies, such as PRRSV and IAV, demonstrating that to minimize the health impact of these endemic bacterial agents it is imperative to establish effective viral control programs., Conclusions: Results from this retrospective study demonstrated significant increases in disease diagnosis for S. suis, G. parasuis, M. hyorhinis, and A. suis, and a significant decrease in detection and disease diagnosis of M. hyosynoviae. High frequencies of interactions between these endemic agents and with viral pathogens was also demonstrated. Consequently, improved control programs are needed to mitigate the adverse effect of these endemic bacterial agents on swine health and wellbeing. This includes improving diagnostic procedures, developing more effective vaccine products, fine-tuning antimicrobial approaches, and managing viral co-infections., (© 2023. The Author(s).)

Introduction: Infection with strongly β-hemolytic strains of Brachyspira hyodysenteriae leads to swine dysentery (SD), a production-limiting disease that causes mucohemorrhagic diarrhea and typhlocolitis in pigs. This pathogen has strong chemotactic activity toward mucin, and infected pigs often have a disorganized mucus layer and marked de novo expression of MUC5AC, which is not constitutively expressed in the colon. It has been shown that fucose is chemoattractant for B. hyodysenteriae , and a highly fermentable fiber diet can mitigate and delay the onset of SD., Methods: We used lectins targeting sialic acids in α-2,6 or α-2,3 linkages, N-acetylglucosamine (GlcNAc), α-linked L-fucose, and an immunohistochemical stain targeting N-glycolylneuraminic acid (NeuGc) to investigate the local expression of these mucin glycans in colonic tissues of pigs with acute SD. We used a commercial enzyme-linked immunosorbent assay (ELISA) to quantify fecal MUC5AC in infected pigs and assess its potential as a diagnostic monitoring tool and RNA in situ hybridization to detect IL-17A in the colonic mucosa., Results: Colonic mucin glycosylation during SD has an overall increase in fucose, a spatially different distribution of GlcNAc with more expression within the crypt lumens of the upper colonic mucosa, and decreased expression or a decreased trend of sialic acids in α-2,6 or α-2,3 linkages, and NeuGc compared to the controls. The degree of increased fucosylation was less in the colonic mucosa of pigs with SD and fed the highly fermentable fiber diet. There was a significant increase in MUC5AC in fecal and colonic samples of pigs with SD at the endpoint compared to the controls, but the predictive value for disease progression was limited., Discussion: Fucosylation and the impact of dietary fiber may play important roles in the pathogenesis of SD. The lack of predictive value for fecal MUC5AC quantification by ELISA is possibly due to the presence of other non-colonic sources of MUC5AC in the feces. The moderate correlation between IL-17A, neutrophils and MUC5AC confirms its immunoregulatory and mucin stimulatory role. Our study characterizes local alteration of mucin glycosylation in the colonic mucosa of pigs with SD after B. hyodysenteriae infection and may provide insight into host-pathogen interaction., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Lin, Helm, Gabler and Burrough.)

Porcine sapovirus (SaV) was first identified by electron microscopy in the United States in 1980 and has since been reported from both asymptomatic and diarrhoeic pigs usually in mixed infection with other enteric pathogens. SaV as the sole aetiological agent of diarrhoea in naturally infected pigs has not previously been reported in the United States. Here, we used four independent lines of evidence including metagenomics analysis, real-time RT-PCR (rRT-PCR), histopathology, and in situ hybridization to confirm porcine SaV genogroup III (GIII) as the sole cause of enteritis and diarrhoea in pigs. A highly sensitive and specific rRT-PCR was established to detect porcine SaV GIII. Examination of 184 faecal samples from an outbreak of diarrhoea on a pig farm showed that pigs with clinical diarrhoea had significantly lower C t values (15.9 ± 0.59) compared to clinically unaffected pigs (35.8 ± 0.71). Further survey of 336 faecal samples from different states in the United States demonstrated that samples from pigs with clinical diarrhoea had a comparable positive rate (45.3%) with those from asymptomatic pigs (43.1%). However, the SaV-positive pigs with clinical diarrhoea had significantly higher viral loads (C t  = 26.0 ± 0.5) than the SAV-positive but clinically healthy pigs (C t  = 33.2 ± 0.9). Phylogenetic analysis of 20 field SaVs revealed that all belonged to SaV GIII and recombination analysis indicated that intragenogroup recombination had occurred within the field isolates of SaV GIII. These results suggest that porcine SaV GIII plays an important aetiologic role in swine enteritis and diarrhoea and rRT-PCR is a reliable method to detect porcine SaV. Our findings provide significant insights to better understand the epidemiology and pathogenicity of porcine SaV infection., (© 2021 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)

Streptococcus equi subspecies zooepidemicus (SEZ) is a commensal bacterium of horses and causes infections in mammalian species, including humans. Historically, virulent strains of SEZ caused high mortality in pigs in China and Indonesia, while disease in the U.S. was infrequent. More recently, high mortality events in sows were attributed to SEZ in North America. The SEZ isolates from these mortality events have high genetic similarity to an isolate from an outbreak in China. Taken together, this may indicate SEZ is an emerging threat to swine health. To generate a disease model and evaluate the susceptibility of healthy, conventionally raised pigs to SEZ, we challenged sows and five-month-old pigs with an isolate from a 2019 mortality event. Pigs were challenged with a genetically similar guinea pig isolate or genetically distinct horse isolate to evaluate comparative virulence. The swine isolate caused severe systemic disease in challenged pigs with 100 % mortality. Disease manifestation in sows was similar to field reports: lethargy/depression, fever, reluctance to rise, and high mortality. The guinea pig isolate also caused severe systemic disease; however, most five-month-old pigs recovered. In contrast, the horse isolate did not cause disease and was readily cleared from the respiratory tract. In conclusion, we were able to replicate disease reported in the field. The results indicate differences in virulence between isolates, with the highest virulence associated with the swine isolate. Additionally, we generated a challenge model that can be used in future research to evaluate virulence factors and disease prevention strategies., (Published by Elsevier B.V.)

Porcine epidemic diarrhea virus (PEDV) infection leads to diarrhea and subsequently to decreased feed efficiency and growth in weaned pigs. Given that few studies have addressed the host-virus interaction in vivo, this study focused on endoplasmic reticulum (ER) stress and unfolded protein response (UPR) in jejunal epithelial cells during PEDV infection. Eight-week-old pigs ( n = 64) were orally inoculated with PEDV IN19338 strain ( n = 40) or sham-inoculated ( n = 24) and analyzed for PEDV viral RNA shedding using reverse transcription-quantitative polymerase chain reaction and for viral antigen within enterocytes using immunohistochemistry (IHC). ER stress was analyzed in a subset of 9 PEDV-inoculated pigs with diarrhea, detectable viral RNA, and viral antigen (PEDV-immunopositive pigs). Compared with control pigs, PEDV-immunopositive pigs had a reduced ratio of villus height to crypt depth in the jejunum ( P = .002, n = 9 per group), consistent with intestinal injury. The protein levels of ATF6, IRE1, PERK, XBP1u, ATF4, GRP78, and caspase-3 were assessed in jejunal epithelial cells at the villus tips via IHC. Both ER stress and UPR were demonstrated in PEDV-immunopositive pigs by the increased expression of ATF6 ( P = .047), IRE1 ( P = .007), and ATF4 ( P = .001). The expression of GRP78 ( P = .024) and caspase-3 ( P = .004) were also increased, indicating an accompanying increase in ER protein folding capacity and apoptosis. Overall, these results reveal that PEDV infection induces ER stress and UPR in intestinal epithelial cells of weaned pigs.

To evaluate trends in bacterial causes of valvular endocarditis in swine, we retrospectively analyzed 321 cases diagnosed at Iowa State University Veterinary Diagnostic Laboratory (Ames, IA, USA) during May 2015--April 2020. Streptococcus gallolyticus was the causative agent for 7.59% of cases. This emerging infection in swine could aid study of endocarditis in humans.

Animal models provide a valuable tool and resource for biomedical researchers as they investigate biological processes, disease pathogenesis, novel therapies, and toxicologic studies. Interpretation of animal model data requires knowledge not only of the processes/diseases being studied but also awareness of spontaneous conditions and background lesions in the model that can influence or even confound the study results. Species, breed/stock, sex, age, anatomy, physiology, diseases (noninfectious and infectious), and neoplastic processes are model features that can impact the results as well as study interpretation. Here, we review these features in several common laboratory animal species, including ferret, dog (beagle), pig, sheep, and goats., (© The Author(s) 2021. Published by Oxford University Press on behalf of the National Academies of Sciences, Engineering, and Medicine. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Lawsonia intracellularis is endemic to swine herds worldwide, however much is still unknown regarding its impact on intestinal function. Thus, this study aimed to characterize the impact of L. intracellularis on digestive function, and how vaccination mitigates these impacts. Thirty-six L. intracellularis negative barrows were assigned to treatment groups (n  =  12/trt): (1) nonvaccinated, L. intracellularis negative (NC); (2) nonvaccinated, L intracellularis challenged (PC); and (3) L. intracellularis challenged, vaccinated (Enterisol ® Ileitis, Boehringer Ingelheim) 7 weeks pre-challenge (VAC). On days post-inoculation (dpi) 0 PC and VAC pigs were inoculated with L. intracellularis. From dpi 19-21 fecal samples were collected for apparent total tract digestibility (ATTD) and at dpi 21, pigs were euthanized for sample collection. Post-inoculation, ADG was reduced in PC pigs compared with NC (41%, P  <  0.001) and VAC (25%, P  <  0.001) pigs. Ileal gross lesion severity was greater in PC pigs compared with NC (P  =  0.003) and VAC (P  =  0.018) pigs. Dry matter, organic matter, nitrogen, and energy ATTD were reduced in PC pigs compared with NC pigs (P  ≤  0.001 for all). RNAscope in situ hybridization revealed abolition of sucrase-isomaltase transcript in the ileum of PC pigs compared with NC and VAC pigs (P  <  0.01). Conversely, abundance of stem cell signaling markers Wnt3, Hes1, and p27 Kip1 were increased in PC pigs compared with NC pigs (P  ≤  0.085). Taken together, these data demonstrate that reduced digestibility during L. intracellularis challenge is partially driven by abolition of digestive machinery in lesioned tissue. Further, vaccination mitigated several of these effects, likely from lower bacterial burden and reduced disease severity.

Every day, thousands of samples from diverse populations of animals are submitted to veterinary diagnostic laboratories (VDLs) for testing. Each VDL has its own laboratory information management system (LIMS), with processes and procedures to capture submission information, perform laboratory tests, define the boundaries of test results (i.e., positive or negative), and report results, in addition to internal business and accounting applications. Enormous quantities of data are accumulated and stored within VDL LIMSs. There is a need for platforms that allow VDLs to exchange and share portions of laboratory data using standardized, reliable, and sustainable information technology processes. Here we report concepts and applications for standardization and aggregation of data from swine submissions to multiple VDLs to detect and monitor porcine enteric coronaviruses by RT-PCR. Oral fluids, feces, and fecal swabs were the specimens submitted most frequently for enteric coronavirus testing. Statistical algorithms were used successfully to scan and monitor the overall and state-specific percentage of positive submissions. Major findings revealed a consistently recurrent seasonal pattern, with the highest percentage of positive submissions detected during December-February for porcine epidemic diarrhea virus, porcine deltacoronavirus, and transmissible gastroenteritis virus (TGEV). After 2014, very few submissions tested positive for TGEV. Monitoring VDL data proactively has the potential to signal and alert stakeholders early of significant changes from expected detection. We demonstrate the importance of, and applications for, data organized and aggregated by using LOINC and SNOMED CTs, as well as the use of customized messaging to allow inter-VDL exchange of information.

Accurate and timely results of diagnostic investigations and laboratory testing guide clinical interventions for the continuous improvement of animal health and welfare. Infectious diseases can severely limit the health, welfare, and productivity of populations of animals. Livestock veterinarians submit thousands of samples daily to veterinary diagnostic laboratories (VDLs) for disease diagnosis, pathogen monitoring, and surveillance. Individual diagnostic laboratory reports are immediately useful; however, aggregated historical laboratory data are increasingly valued by clinicians and decision-makers to identify changes in the health status of various animal populations over time and geographical space. The value of this historical information is enhanced by visualization of trends of agent detection, disease diagnosis, or both, which helps focus time and resources on the most significant pathogens and fosters more effective communication between livestock producers, veterinarians, and VDL professionals. Advances in data visualization tools allow quick, efficient, and often real-time scanning and analysis of databases to inform, guide, and modify animal health intervention algorithms. Value is derived at the farm, production system, or regional level. Visualization tools allow client-specific analyses, benchmarking, formulation of research questions, and monitoring the effects of disease management and precision farming practices. We present here the approach taken to visualize trends of disease occurrence using porcine disease diagnostic code data for the period 2010 to 2019. Our semi-automatic standardized creation of a visualization platform allowed the transformation of diagnostic report data into aggregated information to visualize and monitor disease diagnosis.

Technologic advances in information management have rapidly changed laboratory testing and the practice of veterinary medicine. Timely and strategic sampling, same-day assays, and 24-h access to laboratory results allow for rapid implementation of intervention and treatment protocols. Although agent detection and monitoring systems have progressed, and wider tracking of diseases across veterinary diagnostic laboratories exists, such as by the National Animal Health Laboratory Network (NAHLN), the distinction between detection of agent and manifestation of disease is critical to improved disease management. The implementation of a consistent, intuitive, and useful disease diagnosis coding system, specific for veterinary medicine and applicable to multiple animal species within and between veterinary diagnostic laboratories, is the first phase of disease data aggregation. Feedback loops for continuous improvement that could aggregate existing clinical and laboratory databases to improve the value and applications of diagnostic processes and clinical interventions, with interactive capabilities between clinicians and diagnosticians, and that differentiate disease causation from mere agent detection, remain incomplete. Creating an interface that allows aggregation of existing data from clinicians, including final diagnosis, interventions, or treatments applied, and measures of outcomes, is the second phase. Prototypes for stakeholder cooperation, collaboration, and beta testing of this vision are in development and becoming a reality. We focus here on how such a system is being developed and utilized at the Iowa State University Veterinary Diagnostic Laboratory to facilitate evidence-based medicine and utilize diagnostic coding for continuous improvement of animal health and welfare.

Brachyspira hyodysenteriae is an etiological agent of swine dysentery (SD). Diet fermentability plays a role in development of SD, but the mechanism(s) of action are largely unknown. Thus, this study aimed to determine whether replacing lowly fermentable fiber with highly fermentable fiber would mitigate a 42 d B. hyodysenteriae challenge. Thirty-nine barrows were allocated to dietary treatment groups: (1) 20% corn distillers dried grain with solubles (DDGS), 0% beet pulp (BP) or resistant starch (RS; lowly fermentable fiber (LFF)); (2) 10% DDGS, 5% BP, 5% RS (medium fermentable fiber (MFF)); and (3) 0% DDGS, 10% BP, 10% RS (highly fermentable fiber (HFF)). On day post inoculation 0, pigs were inoculated with B. hyodysenteriae . Overall, 85% LFF pigs developed clinical SD, 46% of MFF pigs developed SD, and 15% of HFF pigs developed SD ( p < 0.05). Overall average daily gain (ADG) differed among all treatments ( p < 0.001), with LFF pigs having the lowest ADG. For HFF pigs, ADG was 37% greater than LFF pigs ( p < 0.001) and 19% greater than MFF pigs ( p = 0.037). The LFF diet had greater relative abundance of Shuttleworthia and Ruminococcus torques . Further, microbiota of pigs that developed SD had enriched Prevotellaceae . Collectively, replacing DDGS with highly fermentable fiber reduced clinical SD, improved performance, and modulated fecal microbiota during B. hyodysenteriae challenge.

This study focused on intestinal restitution including phenotype switching of absorptive enterocytes and the abundance of different enterocyte subtypes in weaned pigs after porcine epidemic diarrhea virus (PEDV) infection. At 10 days post-PEDV-inoculation, the ratio of villus height to crypt depth in both jejunum and ileum had restored, and the PEDV antigen was not detectable. However, enterocytes at the villus tips revealed epithelial-mesenchymal transition (EMT) in the jejunum in which E-cadherin expression decreased while expression of N-cadherin, vimentin, and Snail increased. Additionally, there was reduced expression of actin in microvilli and Zonula occludens-1 (ZO-1) in tight junctions. Moreover, the protein concentration of transforming growth factor β1 (TGFβ1), which mediates EMT and cytoskeleton alteration, was increased. We also found a decreased number of Peyer's patch M cells in the ileum. These results reveal incomplete restitution of enterocytes in the jejunum and potentially impaired immune surveillance in the ileum after PEDV infection., (Copyright © 2020 Elsevier Inc. All rights reserved.)

A flock of budgerigars ( Melopsittacus undulates ) was purchased from a licensed breeder and quarantined at a zoologic facility within the United States in 2016. Following 82 deaths within the flock, the remaining 66 birds were depopulated because of ongoing clinical salmonellosis despite treatment. Gross necropsy was performed on all 66 birds. Histopathologic examination was performed on 10 birds identified with gross lesions and 10 birds without. Pathologic findings were most often observed in the liver, kidney, and spleen. Lesions noted in the livers and spleens were consistent with published reports of salmonellosis in psittacine species. Multisystemic changes associated with septicemia were not noted, most likely because of antibiotic intervention before euthanasia. Of the 20 budgerigars evaluated by histopathology, six had large basophilic intranuclear inclusion bodies within tubular epithelia in a portion of the kidneys. Electronic microscopy, next-generation sequencing, Sanger sequencing, and phylogenetic analyses were used to identify and categorize the identified virus as a novel siadenovirus strain BuAdV-1 USA-IA43444-2016. The strain was 99% similar to budgerigar adenovirus 1 (BuAdV-1), previously reported in Japan, and to a psittacine adenovirus 5 recently identified in a U.S. cockatiel. Salmonella typhimurium carriers were identified via polymerase chain reaction (PCR) and bacterial culture and compared with viral carriers identified via PCR. Inclusion bodies and Salmonella detection were significant in birds with gross lesions versus those without; however, there was no correlation between budgerigars positive with siadenovirus by PCR and concurrent Salmonella infection. Identifying subclinical siadenovirus strain BuAdV-1 USA-IA43444-2016 infection in this flock significantly differs from a previous report of clinical illness in five budgerigars resulting in death caused by BuAdV-1 in Japan. S. typhimurium remains a significant pathogen in budgerigars, and zoonotic concerns prompted depopulation to mitigate the public health risks of this flock.

Swine dysentery ( SD ) induced by Brachyspira hyodysenteriae manifests as mucohemorrhagic diarrhea in pigs, but little is known about the changes that occur to the gastrointestinal tract during this disease. It is thought that dietary fibers alter disease pathogenesis, although the mechanisms of action are unclear. Thus, the objectives of this study were to characterize intestinal integrity, metabolism, and function in pigs during SD and determine if replacing insoluble fiber with fermentable fibers mitigates disease. Thirty-six B. hyodysenteriae -negative gilts [24.3 ± 3.6 kg body weight (BW)] were assigned to one of three treatment groups: (1) B. hyodysenteriae negative, control diet ( NC ); (2) B. hyodysenteriae challenged, control diet (PC); and (3) B. hyodysenteriae challenged, highly fermentable fiber diet (RS). The NC and PC pigs were fed the same control diet, containing 20% corn distillers dried grains with solubles (DDGS). The RS pigs were fed a diet formulated with 5% sugar beet pulp and 5% resistant potato starch. On days post inoculation (dpi) 0 and 1, pigs were inoculated with B. hyodysenteriae or sham. Pigs were euthanized for sample collection after onset of SD. The challenge had high morbidity, with 100% of PC and 75% of RS pigs developing clinical SD. The timing of onset of clinical SD differed due to treatment, with RS pigs having a delayed onset (dpi 9) of clinical SD compared with dpi 7 for PC pigs. Colon transepithelial resistance was increased and macromolecule permeability was reduced in PC pigs compared with NC pigs ( P < 0.01). Minimal changes in ileal permeability, mitochondrial function, or volatile fatty acids (VFAs) were observed. Total VFA concentrations were lower in the colon and cecum in both PC and RS pigs compared to NC pigs (both P < 0.05), but iso-acids were higher (both P < 0.05). Total tract digestibility of dry matter (DM), organic matter (OM), nitrogen (N), and gross energy (GE) was lower in PC pigs compared with both NC and RS pigs (both P < 0.001). These data indicate that SD reduces digestive function but does not reduce ex vivo intestinal integrity. Further, replacement of insoluble fiber with highly fermentable fibers mitigated and delayed the onset of SD., (Copyright © 2020 Helm, Lin, Gabler and Burrough.)

In the small intestine, localized innate mucosal immunity is critical for intestinal homeostasis. Porcine epidemic diarrhea virus (PEDV) infection induces villus injury and impairs digestive function. Moreover, the infection might comprise localized innate mucosal immunity. This study investigated specific enterocyte subtypes and innate immune components of weaned pigs during PEDV infection. Four-week-old pigs were orally inoculated with PEDV IN19338 strain (n = 40) or sham-inoculated (n = 24). At day post inoculation (DPI) 2, 4, and 6, lysozyme expression in Paneth cells, cellular density of villous and Peyer's patch microfold (M) cells, and the expression of polymeric immunoglobulin receptor (pIgR) were assessed in the jejunum and ileum by immunohistochemistry, and interleukin (IL)-1β and tumor necrosis factor (TNF)-α were measured in the jejunum by ELISA. PEDV infection led to a decrease in the ratios of villus height to crypt depth (VH-CD) in jejunum at DPI 2, 4, and 6 and in ileum at DPI 4. The number of villous M cells was reduced in jejunum at DPI 4 and 6 and in ileum at DPI 6, while the number of Peyer's patch M cells in ileum increased at DPI 2 and then decreased at DPI 6. PEDV-infected pigs also had reduced lysozyme expression in ileal Paneth cells at DPI 2 and increased ileal pIgR expression at DPI 4. There were no significant changes in IL-1β and TNF-α expression in PEDV-infected pigs compared to controls. In conclusion, PEDV infection affected innate mucosal immunity of weaned pigs through alterations in Paneth cells, villous and Peyer's patch M cells, and pIgR expression.

Post-weaning diarrhea caused by enterotoxigenic E. coli (ETEC) causes significant economic losses for pig producers. This study was to test the hypotheses that an ETEC challenge disrupts intestinal microbial homeostasis and the inclusion of dietary soluble (10% sugar beet pulp) or insoluble fiber (15% corn distillers dried grains with solubles) with or without exogenous carbohydrases will protect or restore the gut microbial homeostasis in weaned pigs. Sixty crossbred piglets (6.9 ± 0.1 kg) were blocked by body weight and randomly assigned to one of six treatments ( n = 10), including a non-challenged control (NC), ETEC F18-challenged positive control (PC), ETEC-challenged soluble fiber without (SF-) or with carbohydrases (SF+), and ETEC-challenged insoluble fiber without (IF-) or with carbohydrases (IF+). Pigs were housed individually and orally received either ETEC inoculum or PBS-sham inoculum on day 7 post-weaning. Intestinal contents were collected on day 14 or 15. The V4 region of the bacterial 16S rRNA was amplified and sequenced. High-quality reads (total 6,671,739) were selected and clustered into 3,330 OTUs. No differences were observed in α-diversity among treatments. The ileal microbiota in NC and PC had modest separation in the weighted PCoA plot; the microbial structures were slightly altered by SF+ and IF- compared with PC. The PC increased ileal Escherichia-Shigella ( P < 0.01) and numerically decreased Lactobacillus compared to NC. Predicted functional pathways enriched in the ileal microbiota of PC pigs indicated enhanced activity of Gram-negative bacteria, in agreement with increased Escherichia-Shigella . The SF+ tended to decrease ( P < 0.10) ileal Escherichia-Shigella compared to PC. Greater abundance of ileal Streptococcus , Turicibacter , and Roseburia and colonic Prevotella were observed in SF- and SF+ than PC ( P < 0.05). Pigs fed IF + had greater Lactobacillus and Roseburia than PC pigs ( P < 0.05). The ETEC challenge reduced total volatile fatty acid (VFA) compared with NC ( P < 0.05). The SF+ tended to increase ( P < 0.10) and SF- significantly increased ( P < 0.05) colonic total VFA compared with PC. Collectively, ETEC challenge disrupted gut microbial homeostasis and impaired microbial fermentation capacity. Soluble fiber improved VFA production. Dietary fiber and carbohydrases altered microbiota composition to maintain or restore microbial homeostasis., (Copyright © 2020 Li, Peng, Burrough, Sahin, Gould, Gabler, Loving, Dorman and Patience.)

The objective of this experiment was to investigate the impact of an F18 enterotoxigenic Escherichia coli (ETEC) challenge on growth performance, aspects of intestinal function, and selected immune responses of piglets, as well as to evaluate potential protective effects of direct-fed microbial (DFM) blends. Seventy-two weaned piglets (6.4 ± 0.2 kg body weight [BW]; ~21 d of age) were assigned to one of four treatments: 1) NC: Nonchallenged (n = 10), 2) positive challenged control (PC): F18 ETEC-challenged (n = 10), 3) PC + DFM1 (n = 8; three strains of Bacillus amyloliquefaciens; 7.5 × 105 colony-forming units [cfu]/g), or 4) PC + DFM2 (n=8; 2 strains of B. amyloliquefaciens and one strain of Bacillus subtilis; 1.5 × 105 cfu/g). Feed intake and BW were recorded on day 0, 7, and 17. Pigs were sham-infected either with 6 mL phosphate-buffered saline or inoculated with 6 mL F18 ETEC (~1.9 × 109 cfu/mL) on day 7 (0 d postinoculation [dpi]). All ETEC-challenged pigs were confirmed to be genetically susceptible to F18. Pigs had ad libitum access to feed and water throughout the 17-d trial. Fecal scores were visually ranked and rectal temperatures were recorded daily. To evaluate ETEC shedding, fecal swabs were collected on dpi 0, 1, 2, 3, 5, 7, and 10. Blood samples were collected on dpi 0, 1, 2, 4, 7, and 10. Ileal tissues were collected at necropsy on dpi 10. All challenged treatments had lower final BW, decreased average daily gain (ADG), and average daily feed intake (ADFI) during the 10-d postchallenge period (P < 0.01). The DFM2 treatment increased E. coli shedding on dpi 2 and decreased iton dpi 7 (P < 0.05) compared with the PC. Rectal temperature decreased across all challenged treatments (P < 0.01). Ileal mRNA abundance of occludin (OCLN) and zonula occludens-1 (ZO-1) decreased in PC and DFM1 compared with NC (P < 0.05). Pigs fed DFM2 had intermediate ileal mRNA abundance of OCLN and increased ZO-1 mRNA compared with pigs in PC (P < 0.05). Interleukin 8 (IL-8) increased in the plasma of PC and DFM2 on dpi 2 compared with NC (P < 0.05). Mucosal IL-8 increased in PC compared with NC (P < 0.05). All challenged treatments tended to have elevated tumor necrosis factor-α (TNF-α) mRNA abundance compared with NC (P < 0.10). Challenged pigs had reduced secretory immunoglobulin A and villus height compared with NC pigs (P < 0.05). The impact of an ETEC challenge on intestinal function and the immune system has been revealed, information critical to developing improved treatment regimes., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

We developed a model to predict the cyclic pattern of porcine reproductive and respiratory syndrome virus (PRRSV) RNA detection by reverse-transcription real-time PCR (RT-rtPCR) from 4 major swine-centric veterinary diagnostic laboratories (VDLs) in the United States and to use historical data to forecast the upcoming year's weekly percentage of positive submissions and issue outbreak signals when the pattern of detection was not as expected. Standardized submission data and test results were used. Historical data (2015-2017) composed of the weekly percentage of PCR-positive submissions were used to fit a cyclic robust regression model. The findings were used to forecast the expected weekly percentage of PCR-positive submissions, with a 95% confidence interval (CI), for 2018. During 2018, the proportion of PRRSV-positive submissions crossed 95% CI boundaries at week 2, 14-25, and 48. The relatively higher detection on week 2 and 48 were mostly from submissions containing samples from wean-to-market pigs, and for week 14-25 originated mostly from samples from adult/sow farms. There was a recurring yearly pattern of detection, wherein an increased proportion of PRRSV RNA detection in submissions originating from wean-to-finish farms was followed by increased detection in samples from adult/sow farms. Results from the model described herein confirm the seasonal cyclic pattern of PRRSV detection using test results consolidated from 4 VDLs. Wave crests occurred consistently during winter, and wave troughs occurred consistently during the summer months. Our model was able to correctly identify statistically significant outbreak signals in PRRSV RNA detection at 3 instances during 2018.

Since 2014, Salmonella 4,[5],12:i:- has emerged as the most common serovar of Salmonella enterica identified from swine samples submitted to veterinary diagnostic laboratories in the United States. To compare the pathogenicity of S . 4,[5],12:i:- in swine to the known pathogenic Salmonella Typhimurium and lesser pathogenic Salmonella Derby, 72 pigs (20 per Salmonella serovar treatment and 12 controls) were inoculated with either S . Typhimurium, S . 4,[5],12:i:-, S . Derby, or sham-inoculated and followed for up to 28 days thereafter via rectal temperature, fecal scoring, and fecal culture. Animals were euthanized on days 2, 4, or 28 to determine the gross and histopathologic signs of disease and tissue colonization. The results clearly demonstrate that for the isolates selected, serovar 4,[5],12:i:- possesses similar ability as serovar Typhimurium to cause clinical disease, colonize the tonsils and ileocecal lymph nodes, and be shed in the feces of infected swine past resolution of clinical disease. To compare the competitive fitness of S . 4,[5],12:i:- to S . Typhimurium in swine when co-infected, 12 pigs were co-inoculated with equal concentrations of both S . Typhimurium and S . 4,[5],12:i and followed for up to 10 days thereafter. When co-inoculated, serovar 4,[5],12:i:- was consistently detected in the feces of a higher percentage of pigs and at higher concentrations than serovar Typhimurium, suggesting an increased competitive fitness of 4,[5],12:i:- relative to serovar Typhimurium when inoculated simultaneously into naïve pigs. Whole genome sequencing analysis of the isolates used in these studies revealed similar virulence factor presence in all S . 4,[5],12:i:- and S . Typhimurium isolates, but not S . Derby, providing additional evidence for similar pathogenicity potential between serovars 4,[5],12:i:- and Typhimurium. Altogether, this data strongly supports the hypothesis that S . 4,[5],12:i:- is a pathogen of swine and suggests a mechanism through increased competitive fitness for the increasing identification of Salmonella 4,[5],12:i:- in swine diagnostic samples over the past several years., (Copyright © 2020 Naberhaus, Krull, Arruda, Arruda, Sahin, Schwartz, Burrough, Magstadt, Matias Ferreyra, Gatto, Meiroz de Souza Almeida, Wang and Kreuder.)

Pathogen challenges are often accompanied by reductions in feed intake, making it difficult to differentiate impacts of reduced feed intake from impacts of pathogen on various response parameters. Therefore, the objective of this study was to determine the impact of Porcine Reproductive and Respiratory Syndrome virus (PRRSV) and feed intake on parameters of jejunal function and integrity in growing pigs. Twenty-four pigs (11.34 ± 1.54 kg BW) were randomly selected and allotted to 1 of 3 treatments (n = 8 pigs/treatment): 1) PRRSV naïve, ad libitum fed (Ad), 2) PRRSV-inoculated, ad libitum fed (PRRS+), and 3) PRRSV naïve, pair-fed to the PRRS+ pigs' daily feed intake (PF). At 17 days post inoculation, all pigs were euthanized and the jejunum was collected for analysis. At days post inoculation 17, PRRS+ and PF pigs had decreased (P < 0.05) transepithelial resistance compared with Ad pigs; whereas fluorescein isothiocyanate-dextran 4 kDa permeability was not different among treatments. Active glucose transport was increased (P < 0.05) in PRRS+ and PF pigs compared with Ad pigs. Brush border carbohydrase activity was reduced in PRRS+ pigs compared with PF pigs for lactase (55%; P = 0.015), sucrase (37%; P = 0.002), and maltase (30%; P = 0.015). For all three carbohydrases, Ad pigs had activities intermediate that of PRRS+ and PF pigs. The mRNA abundance of the tight junction proteins claudin 2, claudin 3, claudin 4, occludin, and zonula occludens-1 were reduced in PRRS+ pigs compared with Ad pigs; however, neither the total protein abundance nor the cellular compartmentalization of these tight junction proteins differed among treatments. Taken together, this study demonstrates that the changes that occur to intestinal epithelium structure, function, and integrity during a systemic PRRSV challenge can be partially explained by reductions in feed intake. Further, long term adaptation to PRRSV challenge and caloric restriction does reduce intestinal transepithelial resistance but does not appear to reduce the integrity of tight junction protein complexes., Competing Interests: The authors have declared that no competing interests exist.

Porcine sapoviruses (SaVs) are genetically diverse and widely distributed in pig-producing countries. Eight genogroups of porcine SaV have been identified, and genogroup III is the predominant type. Most of the eight genogroups of porcine SaV are circulating in the United States. In the present study, we report detection of porcine SaVs in pigs at different ages with clinical diarrhoea using next-generation sequencing and genetic characterization. All seven cases have porcine SaV GIII strains detected and one pooled case was found to have a porcine SaV GVI strain IA27912-B-2018. Sequence analysis showed that seven GIII isolates were genetically divergent and formed four different lineages on the trees of complete genome, RdRP, VP1 and VP2. In addition, these seven GIII isolates had three different deletion/insertion patterns in an identified variable region close to the 3' end of VP2. The GVI strain IA27912-B-2018 was closely related to strains previously detected in the United States and Japan. A 3-nt deletion in VP1 region of GVI IA27912-B-2018 was identified. Our study showed that genetically divergent SaVs of different genogroups are co-circulating in pigs in the United States. Future studies comparing the virulence of these different genogroups in pigs are needed to better understand this virus and to determine if surveillance and vaccine development are needed to monitor and control porcine SaVs., (© 2019 Blackwell Verlag GmbH.)

In the past decade, different members of the genus Mamastrovirus have been associated with outbreaks of neurologic disease in humans, cattle, sheep, mink, and, most recently, porcine astrovirus 3 (PoAstV3) in swine. We performed a retrospective analysis of 50 cases of porcine neurologic disease of undetermined cause but with microscopic lesions compatible with a viral encephalomyelitis to better understand the role and pathogenesis of PoAstV3 infection. Nucleic acid was extracted from formalin-fixed paraffin-embedded (FFPE) tissue for reverse transcription quantitative polymerase chain reaction (RT-qPCR) testing for PoAstV3. In addition, 3 cases with confirmed PoAstV3-associated disease were assayed by RT-qPCR to investigate PoAstV3 tissue distribution. PoAstV3 was detected in central nervous system (CNS) tissue via RT-qPCR and in situ hybridization in 13 of 50 (26%) FFPE cases assayed. PoAstV3 was rarely detected in any tissues outside the CNS. Positive cases from the retrospective study included pigs in various production categories beginning in 2010, the earliest year samples were available. Based on these results, PoAstV3 appears to be a recurring putative cause of viral encephalomyelitis in swine that is rarely detected outside of the CNS at the time of clinical neurologic disease, unlike other common viral causes of neurologic disease in swine.

Rapid identification of the infecting Salmonella serovar from porcine diagnostic samples is vital to allow implementation of appropriate on-farm treatment and management decisions. Although identification at the serogroup level can be rapidly achieved at most veterinary diagnostic laboratories, final Salmonella serovar identification often takes several weeks because of the limited number of reference laboratories performing the complex task of serotyping. Salmonella serogroup B, currently the dominant serogroup identified from swine clinical samples in the United States, contains serovars that vary from highly pathogenic to minimally pathogenic in swine. We determined the frequency of detection of individual group B serovars at the Iowa State Veterinary Diagnostic Laboratory from 2008 to 2017, and validated a multiplex real-time PCR (rtPCR) to distinguish pathogenic serogroup B serovars from those of lesser pathogenicity. Our results indicate that, since 2014, Salmonella enterica ssp. enterica serovar 4,[5],12:i:- has been the dominant serovar identified from swine clinical samples at the ISU-VDL, with S. Typhimurium now the second most common serovar identified. We developed a rtPCR to allow rapid differentiation of samples containing S. 4,[5],12:i:- and S. Typhimurium from samples containing serovars believed to be of less pathogenicity, such as S. Agona and S. Derby. When combined with enrichment culture, this rtPCR has the ability to significantly improve the time to final serovar identification of the 2 most commonly identified pathogenic Salmonella serovars in swine, and allows rapid implementation of serovar-specific intervention strategies.

This project investigates the macroepidemiological aspects of porcine reproductive and respiratory syndrome virus (PRRSV) RNA detection by veterinary diagnostic laboratories (VDLs) for the period 2007 through 2018. Standardized submission data and PRRSV real-time reverse-transcriptase polymerase chain reaction (RT-qPCR) test results from porcine samples were retrieved from four VDLs representing 95% of all swine samples tested in NAHLN laboratories in the US. Anonymized data were retrieved and organized at the case level using SAS (SAS® Version 9.4, SAS® Institute, Inc., Cary, NC) with the use of PROC DATA, PROC MERGE, and PROC SQL scripts. The final aggregated and anonymized dataset comprised of 547,873 unique cases was uploaded to Power Business Intelligence-Power BI® (Microsoft Corporation, Redmond, Washington) to construct dynamic charts. The number of cases tested for PRRSV doubled from 2010 to 2018, with that increase mainly driven by samples typically used for monitoring purposes rather than diagnosis of disease. Apparent seasonal trends for the frequency of PRRSV detection were consistently observed with a higher percentage of positive cases occurring during fall or winter months and lower during summer months, perhaps due to increased testing associated with well-known seasonal occurrence of swine respiratory disease. PRRSV type 2, also known as North American genotype, accounted for 94.76% of all positive cases and was distributed across the US. PRRSV type 1, also known as European genotype, was geographically restricted and accounted for 2.15% of all positive cases. Co-detection of both strains accounted for 3.09% of the positive cases. Both oral fluid and processing fluid samples, had a rapid increase in the number of submissions soon after they were described in 2008 and 2017, respectively, suggesting rapid adoption of these specimens by the US swine industry for PRRSV monitoring in swine populations. As part of this project, a bio-informatics tool defined as Swine Disease Reporting System (SDRS) was developed. This tool has real-time capability to inform the US swine industry on the macroepidemiological aspects of PRRSV detection, and is easily adaptable for other analytes relevant to the swine industry., Competing Interests: Paul Sundberg holds the position of Executive Director of SHIC, which provided funding to this project. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Porcine reproductive and respiratory syndrome (PRRS) virus is one of the most economically significant pig pathogens worldwide. However, the metabolic explanation for reductions in tissue accretion observed in growing pigs remains poorly defined. Additionally, PRRS virus challenge is often accompanied by reduced feed intake, making it difficult to discern which effects are virus vs. feed intake driven. To account for this, a pair-fed model was employed to examine the effects of PRRS challenge and nutrient restriction on skeletal muscle and liver metabolism. Forty-eight pigs were randomly selected (13.1 ± 1.97 kg BW) and allotted to 1 of 3 treatments (n = 16 pigs/treatment): 1) PRRS naïve, ad libitum fed (Ad), 2) PRRS-inoculated, ad libitum fed (PRRS+), and 3) PRRS naïve, pair-fed to the PRRS-inoculated pigs' daily feed intake (PF). At days postinoculation (dpi) 10 and 17, 8 pigs per treatment were euthanized and tissues collected. Tissues were assayed for markers of proteolysis (LM only), protein synthesis (LM only), oxidative stress (LM only), gluconeogenesis (liver), and glycogen concentrations (LM and liver). Growth performance, feed intake, and feed efficiency were all reduced in both PRRS+ and PF pigs compared with Ad pigs (P < 0.001). Furthermore, growth performance and feed efficiency were additionally reduced in PRRS+ pigs compared with PF pigs (P < 0.05). Activity of most markers of LM proteolysis (μ-calpain, 20S proteasome, and caspase 3/7) was not increased (P > 0.10) in PRRS+ pigs compared with Ad pigs, although activity of m-calpain was increased in PRRS+ pigs compared with Ad pigs (P = 0.025) at dpi 17. Muscle reactive oxygen species production was not increased (P > 0.10) in PRRS+ pigs compared with Ad pigs. However, phosphorylation of protein synthesis markers was decreased in PRRS+ pigs compared with both Ad (P < 0.05) and PF (P < 0.05) pigs. Liver gluconeogenesis was not increased as a result of PRRS; however, liver glycogen was decreased (P < 0.01) in PRRS+ pigs compared with Ad and PF pigs at both time points. Taken together, this work demonstrates the differential impact a viral challenge and nutrient restriction have on metabolism of growing pigs. Although markers of skeletal muscle proteolysis showed limited evidence of increase, markers of skeletal muscle synthesis were reduced during PRRS viral challenge. Furthermore, liver glycogenolysis seems to provide PRRS+ pigs with glucose needed to fuel the immune response during viral challenge., (© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Zinc oxide (ZnO) is commonly fed to pigs at pharmacologic concentrations (2,000-3,000 ppm) for the first 3 wk post-weaning to increase growth and reduce enteric bacterial disease. The safety of this high-dose treatment is assumed based upon lower bioavailability of ZnO compared to other common forms of Zn in feed; however, limited data are available regarding the specific serum and tissue concentrations of Zn expected in animals experiencing overload following feeding of excessive ZnO. Fifty-five 3-wk-old pigs were divided into 5 groups receiving various concentrations of ZnO (0-6,000 ppm) for 3 wk. Pigs receiving 6,000 ppm ZnO had higher mean pancreatic Zn concentrations ( p < 0.001) compared to other treatments, and higher pancreatic Zn concentrations were associated with pancreatic acinar cell apoptosis ( p < 0.0001). Hepatic Zn concentrations were highest for pigs receiving 6,000 ppm ZnO (mean ± SEM; 729 ± 264 ppm) and significantly higher than all other groups ( p < 0.0001), with controls having concentrations <60 ppm. Similarly, serum Zn was highest in pigs receiving 6,000 ppm ZnO (4.81 ± 2.31 ppm) and significantly higher than all groups (controls, <1 ppm). Additionally, as pigs became overloaded with Zn, there were significant reductions in serum Cu and both serum and hepatic Se. Hepatic and serum Zn concentrations >500 ppm and >2 ppm, respectively, are indicative of Zn overload, and dietary trace mineral analysis is warranted if expected inclusion rates are ≤3,000 ppm ZnO.

Salmonella enterica serotype I 4,[5],12:i:- has been increasingly isolated from swine. However, its pathogenic potential is not well characterized. Analysis of swine cases confirmed a strong positive association between isolation of I 4,[5],12:i:- and lesions of enteric salmonellosis and suggested a similar pathogenic potential as that for Salmonella Typhimurium.

This study aimed to evaluate the effects of a source of dietary soluble (SF) and insoluble fiber (IF) without or with exogenous carbohydrases (xylanase, β-glucanase, and pectinase) on diarrhea incidence, selected immune responses, and growth performance in enterotoxigenic Escherichia coli (ETEC)-challenged pigs. Sixty weaned pigs (6.9 ± 0.1 kg BW, ~23 d of age) were blocked by initial BW and placed in individual pens. Pens were randomly assigned to one of six treatments (n = 10 per treatment), including a nonchallenged control (NC), a positive challenge control (PC), the PC + a soluble fiber diet (10% sugar beet pulp) without (SF-) or with carbohydrases (SF+), and PC + an IF diet (15% corn distillers dried grains with solubles) without (IF-) or with carbohydrases (IF+). The control diet was primarily based on corn and soybean meal with 13.5% whey powder. The two sources of fiber were added at the expense of cornstarch in the control diet. Pigs were orally inoculated with 6 mL hemolytic F18 ETEC (~3.5 × 109 cfu/mL) or sham infected with 6 mL phosphate-buffered saline on day 7 (0 d postinoculation, dpi) postweaning. All ETEC challenged pigs were confirmed to be genetically susceptible to F18 ETEC. Pigs had free access to feed and water throughout the 14-d trial. Pig BW and feed intake were recorded on dpi -7, 0, and 7 or 8. Fecal swabs were collected on dpi -7, 0, 1, 2, 3, 5, and 7 or 8 to evaluate hemolytic E. coli shedding. Fecal score was visually ranked daily postchallenge to evaluate diarrhea incidence. Blood samples were collected on dpi -1, 3, and 7 or 8 at necropsy and intestinal tissues were collected at necropsy. Pigs on PC had lower dpi 1 to 7 ADG and ADFI than those on NC (P < 0.05). Compared with PC pigs, SF+ pigs had greater ADG during both pre- and postchallenge period (P < 0.05). The IF- increased postchallenge diarrhea incidence compared with PC (P < 0.05). Pigs on SF- had lower ileal E. coli attachment than PC (P < 0.05). The SF+ reduced haptoglobin and IF+ reduced C-reactive protein on dpi 3 compared with PC (P < 0.05). Compared with PC pigs, SF+ pigs tended to have lower ileal tumor necrosis factor alpha and greater ileal occludin (OCLN) mRNA (P < 0.10) and had greater (P < 0.05) colonic OCLN mRNA levels. Collectively, IF- increased incidence of diarrhea and fecal E. coli shedding compared with PC. The SF+ pigs had improved growth compared with PC pigs, likely due in part to a reduction in inflammatory intermediates., (© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Brachyspira (B.) hyodysenteriae is widespread globally, and can cause mucohaemorrhagic colitis (swine dysentery, SD) with severe economic impact in infected herds. Typical strains of B. hyodysenteriae are strongly haemolytic on blood agar, and the haemolytic activity is believed to contribute to virulence in vivo. However, recently there have been reports of atypical weakly haemolytic isolates of B. hyodysenteriae (whBh). In this study, 34 European whBh and 82 strongly haemolytic isolates were subjected to comparative genomic analysis. A phylogenetic tree constructed using core single nucleotide polymorphisms showed that the whBh formed a distinct sub-clade. All eight genes previously associated with haemolysis in B. hyodysenteriae were present in the whBh. No consistent patterns of amino acid substitutions for all whBh were found in these genes. In contrast, a genome region containing six coding sequences (CDSs) had consistent nucleotide sequence differences between strongly and whBh isolates. Two CDSs were predicted to encode ABC transporter proteins, and a TolC family protein, which may have a role in the export of haemolysins from B. hyodysenteriae. Another difference in this region was the presence of three CDSs in whBh that are pseudogenes in strongly haemolytic isolates. One of the intact CDSs from whBh encoded a predicted PadR-like transcriptional repressor that may play a role in repression of haemolysis functions. In summary, a sub-clade of whBh isolates has emerged in Europe, and several genomic differences, that potentially explain the weakly haemolytic phenotype, were identified. These markers may provide targets for discriminatory molecular tests needed in SD surveillance.

Brachyspira hyodysenteriae (Bhyo) induces mucohemorrhagic diarrhea in pigs and is an economically significant disease worldwide. Our objectives were to determine the impact of Bhyo on apparent total tract digestibility (ATTD), ileal digestibility (AID), and ileal basal endogenous losses (BEL) in grower pigs. In addition, we assessed the effect of Bhyo on hindgut disappearance of DM, N, and GE. Thirty-two Bhyo negative gilts (38.6 ± 0.70 kg BW) were fitted with a T-cannula in the distal ileum and individually penned. In replicates 1 and 2, pigs were fed a complete diet (7 Bhyo-, 10 Bhyo+ pigs) or nitrogen-free diet (NFD; 4 Bhyo-, 11 Bhyo+ pigs), respectively. Across multiple rooms, the 21 Bhyo+ pigs (62.6 ± 1.39 kg BW) were inoculated with Bhyo on day post inoculation (dpi) 0, and the 11 Bhyo- pigs were sham inoculated. Feces were collected from 9 to 11 dpi and ileal digesta collected from 12 to 13 dpi. All pigs were euthanized at 14 to 15 dpi and intestinal tract pathology assessed. Within the complete diet and NFD treatments, data were analyzed to determine pathogen effects. All Bhyo- pigs remained Bhyo negative, and 5 Bhyo+ pigs in each replicate were confirmed Bhyo positive within 9 dpi. Infection with Bhyo reduced ATTD of DM, N, and GE and increased AID of Gly (P < 0.05). No other AA AID differences were observed. Only BEL of Pro was reduced (P < 0.05) while Arg, Trp, and Gly tended (P < 0.10) to be reduced in Bhyo+ pigs. When calculated from AID and BEL, Bhyo infection reduced standardized ileal digestibility (SID) of N, Arg, Lys, Ala, Gly, Pro, and Ser (P < 0.05) and tended to reduce Thr SID (P = 0.09). In the hindgut of Bhyo+ pigs, there was generally an appearance of nutrients rather than disappearance. In Bhyo+ pigs fed a complete diet, hindgut appearance of N and GE were increased (P < 0.05) by 58 and nine-fold, respectively, and DM tended to be increased two-fold (P = 0.06). Similarly, in NFD fed pigs, hindgut appearance of N and GE was increased by 172% and 162%, respectively, although high variability led to no significance. Altogether, Bhyo infection decreases ATTD but has minimal impact on AID of AA, when corrected for BEL, SID of N, Arg, Lys and some nonessential AA are specifically reduced. Unexpectedly, BEL of several AA involved in mucin production were unaffected by Bhyo infection. This may suggest an increased need for specific AA and energy during a Bhyo challenge.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a significant disease in the swine industry, and increasing soybean meal (SBM) consumption during this disease challenge may improve performance. Our objectives were to determine the impact of SBM level on apparent total tract (ATTD) and ileal (AID) digestibility during PRRSV infection and to determine ileal basal endogenous losses (BEL) during PRRSV infection. Forty PRRSV negative gilts were fitted with a T-cannula in the distal ileum. Treatments were arranged in a 2 × 2 factorial with high and low SBM (HSBM, 29% vs. LSBM, 10%), with and without PRRSV (n = 6/treatment). The remaining pigs (n = 8/challenge status) were fed a N-free diet. Chromic oxide was used as an indigestible marker. On day post inoculation (dpi) 0, at 47.7 ± 0.57 kg BW, 20 pigs were inoculated with live PRRSV; 20 control pigs were sham inoculated. Infection was confirmed by serum PCR. Feces were collected at dpi 5 to 6 and dpi 16 to 17, and ileal digesta collected at dpi 7 to 8 and dpi 18 to 19. Feed, feces, and digesta were analyzed for DM, N, and GE. Digesta and feed were analyzed for AA. Data were analyzed in a 2 × 2 + 2 factorial design to determine main effects of diet and PRRSV and their interaction. Data from N-free fed pigs were analyzed separately to determine BEL and hindgut disappearance due to PRRSV infection. All control pigs remained PRRSV negative. There were no interactions for AID of AA; however, HSBM reduced DM, GE, Lys, and Met AID and increased Arg and Gly AID during both collection periods (P < 0.05). At dpi 7 to 8 only, PRRSV reduced DM and GE AID (P < 0.05). At 7 to 8 dpi, BEL of Arg, Ala, and Pro were reduced (P < 0.05) due to PRRSV by 64%, 39%, and 94%, respectively. At dpi 18 to 19, BEL of Thr tended (P = 0.06) to be increased in PRRSV-infected pigs; however, no other differences were observed. Pigs fed LSBM had increased Lys, Met, Thr, Trp, and Pro standardized ileal digestibility (SID), primarily at 7 to 8 dpi. At 7 to 8 dpi, PRRSV reduced Arg, Gly, and Pro SID (P < 0.01), and SID Pro continued to be reduced by 17% at dpi 18 to 19. Compared with HSBM pigs, LSBM reduced hindgut disappearance of DM and GE at dpi 5 to 8 and dpi 16 to 19, while N disappearance was reduced at dpi 5 to 8. There were no differences between control and PRRSV N-free fed pigs. Altogether, SBM inclusion impacts SID of AA and hindgut disappearance of nutrients, regardless of PRRSV. In contrast, there is minimal impact of PRRSV on BEL, and therefore, SID of most AA are not different.

The anaerobic intestinal spirochaete Brachyspira (B. ) suanatina was first described in 2007 but since then no further isolates have been reported from pigs. Accordingly, when the species was validly published in 2016, the overall occurrence and clinical relevance in pigs were unknown. In a fattening farm in southern Germany, mucohaemorrhagic diarrhoea was observed in 60 per cent (750 animals) of the finisher pigs. A diagnostic workup including Brachyspira culture, Salmonella culture, Lawsonia intracellularis- specific, B. hyodysenteriae -specific and B. pilosicoli -specific multiplex PCR and postmortem examination of severely affected pigs was performed. Tests for Salmonella species, Lawsonia intracellularis and B. hyodysenteriae were all negative. Gross and microscopic lesions were in agreement with dysentery and spirochaetes could be demonstrated by silver staining in tissue samples of the caecum at the ileal papilla. B. suanatina was cultured from faeces or colon of all (five) animals sampled and identified using nox -RFLP, partial nox -gene-sequencing and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). According to the initial report from Scandinavia, B. suanatina can be isolated from birds and cross-species infection could be demonstrated infecting pigs with an avian isolate. Thus outdoor production as in the case presented here and international trade may pose a risk for infection of naive herds., Competing Interests: Competing interests: None declared., (© British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Porcine epidemic diarrhea virus (PEDV) infects enterocytes and in nursery pigs, results in diarrhea, anorexia, and reduced performance. Therefore, the objective of this study was to determine how PEDV infection influenced growth performance and repartitioning of amino acids and energy in nursery pigs. A total of 32 barrows and gilts, approximately 1 wk post-wean (BW = 8.46 ± 0.50 kg), and naïve for PEDV were obtained, weighed, and allotted based on sex and BW to one of two treatments: 1) Control, PEDV naïve and 2) PEDV-inoculated (PEDV) with eight pens of two pigs each per treatment. On day post-inoculation (dpi) 0, PEDV pigs were inoculated via intragastric gavage with PEDV isolate (USA/Iowa/18984/2013). Pig and feeder weights were recorded at dpi -7, 0, 5, and 20 in order to calculate ADG, ADFI, and G:F. Eight pigs per treatment were euthanized on dpi 5 and 20, and tissues and blood were collected. At dpi 5, all PEDV pigs were PCR positive for PEDV in feces. Overall, PEDV pigs tended (P < 0.10) to increase ADFI, which resulted in reduced (P < 0.05) feed efficiency. At dpi 5, PEDV pigs had reduced (P < 0.05) villus height and increased (P < 0.05) stem cell proliferation in the jejunum compared with Control pigs. Pigs inoculated with PEDV had increased (P < 0.05) serum haptoglobin and increased insulin-to-glucose ratios compared with Control pigs at dpi 5. Markers of muscle proteolysis were not different (P > 0.05) between treatments within dpi; however, at dpi 5, 20S proteasome activity was increased (P < 0.05) in longissimus dorsi of PEDV pigs compared with Control pigs. Liver and jejunum gluconeogenic enzyme activities were not different (P > 0.05) between treatments within dpi. Overall, PEDV-inoculated pigs did recover the absorptive capacity that was reduced during PEDV infection by increasing proliferation of intestinal stem cells. However, the energy and nutrients needed to recover the epithelium may be originating from available luminal nutrients instead of muscle proteolysis and gluconeogenesis. This study provides insight into the effects of an enteric coronavirus on postabsorptive metabolism in nursery pigs.

The pig intestinal epithelium can be compromised by pathogens leading to reduced integrity and function. Porcine epidemic diarrhea virus (PEDV), recently detected in North America, exemplifies intestinal epithelial insult. Although several studies have investigated the molecular aspects and host immune response to PEDV, there are little data on the impact of PEDV on pig intestinal physiology. The objective of this study was to investigate the longitudinal impact of PEDV on nursery pig intestinal function and integrity. Fifty recently-weaned, 5-week-old barrows and gilts (BW=9.92±0.49kg) were sorted based on body weight (BW) and sex into two treatments: 1) Control or 2) PEDV inoculated. At 2, 5, 7, and 14days post inoculation (dpi), 4 pigs per treatment were euthanized and jejunum sections collected. PEDV antigen was detected in inoculated pigs by immunohistochemistry in 50% (2/4) at dpi 2, 100% (4/4) at dpi 5, and none at later time points. PEDV-infected pigs had reduced (P<0.05) villus height and decreased transepithelial resistance compared with controls. Total acidic mucins, particularly sialomucin, were reduced in PEDV pigs at dpi 2 and then increased compared with controls at dpi 7 and 14. In addition, PEDV pigs had increased stem cell proliferation (P<0.05) and a numerical increase in DNA fragmentation compared with controls through dpi 7 which coincided with an observed return of digestive function to that of controls. Collectively, these data reveal that PEDV infection results in time-dependent changes not only in intestinal morphology but also barrier integrity and function., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Colonic contents and mucosal scrapings from pigs inoculated with Brachyspira hyodysenteriae or Brachyspira hampsonii were collected at necropsy and classified as either positive ( n  = 29) or negative ( n  = 7) for swine dysentery (SD) based upon lesions and positive culture from the source pig. The microbiota in each sample was analyzed by bacterial census taking (16S rRNA gene sequencing). Procrustes analysis revealed similar clustering by disease classification with a relatively high M2 value (0.44) suggesting differences in the microbiota between mucosal and luminal samples from the same pig. In both sample types, differences in richness and beta diversity were observed between disease statuses ( P  ≤ 0.014). The relative abundance of Brachyspirales, Campylobacterales, Desulfovibrionales , and Enterobacteriales was higher in pigs with dysentery for both mucosal scrapings and luminal samples while Clostridiales, Erysipelotrichales , and Fusobacteriales were significantly more abundant in the luminal contents only. For inoculated pigs that did not develop dysentery, Burkholderiales were more abundant in both sample types, Bacteroidales and Synergistales were more abundant in mucosal scrapings, and Lactobacillales and Bifidobacteriales were more abundant in luminal contents when compared with diseased pigs. Linear discriminant analysis of effect size revealed Brachyspira, Campylobacter, Mogibacterium , and multiple Desulfovibrio spp. as differential features in mucosal scrapings from pigs with dysentery while Lactobacillus and a Bifidobacterium spp. were differential in pigs without disease. These differential features were not observed in luminal samples. In summary, microbial profiles in both sample types differ significantly between disease states; however, evaluation of the mucosal microbiome specifically may be of higher value in elucidating bacterial mechanisms underlying development of SD.

Campylobacter jejuni is a zoonotic pathogen, and a hypervirulent clone, named clone SA, has recently emerged as the predominant cause of ovine abortion in the United States. To induce abortion, orally ingested Campylobacter must translocate across the intestinal epithelium, spread systemically in the circulation, and reach the fetoplacental tissue. Bacterial factors involved in these steps are not well understood. C. jejuni is known to produce capsular polysaccharide (CPS), but the specific role that CPS plays in systemic infection and particularly abortion in animals remains to be determined. In this study, we evaluated the role of CPS in bacteremia using a mouse model and in abortion using a pregnant guinea pig model following oral challenge. Compared with C. jejuni NCTC 11168 and 81-176, a clone SA isolate (IA3902) resulted in significantly higher bacterial counts and a significantly longer duration of bacteremia in mice. The loss of capsule production via gene-specific mutagenesis in IA3902 led to the complete abolishment of bacteremia in mice and abortion in pregnant guinea pigs, while complementation of capsule expression almost fully restored these phenotypes. The capsule mutant strain was also impaired for survival in guinea pig sera and sheep blood. Sequence-based analyses revealed that clone SA possesses a unique CPS locus with a mosaic structure, which has been stably maintained in all clone SA isolates derived from various hosts and times. These findings establish CPS as a key virulence factor for the induction of systemic infection and abortion in pregnant animals and provide a viable candidate for the development of vaccines against hypervirulent C. jejuni ., (Copyright © 2017 American Society for Microbiology.)

Swine dysentery is a severe enteric disease in pigs, which is characterized by bloody to mucoid diarrhea and associated with reduced growth performance and variable mortality. This disease is most often observed in grower-finisher pigs, wherein susceptible pigs develop a significant mucohemorrhagic typhlocolitis following infection with strongly hemolytic spirochetes of the genus Brachyspira. While swine dysentery is endemic in many parts of the world, the disease had essentially disappeared in much of the United States by the mid-1990s as a result of industry consolidation and effective treatment, control, and elimination methods. However, since 2007, there has been a reported increase in laboratory diagnosis of swine dysentery in parts of North America along with the detection of novel pathogenic Brachyspira spp worldwide. Accordingly, there has been a renewed interest in swine dysentery and Brachyspira spp infections in pigs, particularly in areas where the disease was previously eliminated. This review provides an overview of knowledge on the etiology, pathogenesis, and diagnosis of swine dysentery, with insights into risk factors and control.

Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) are both members of the family which induce clinical signs of diarrhea, dehydration, and in some circumstances, mortality. Most research has been focused on isolation, genome sequencing, pathogenicity, and virulence of these viruses, but there is little information on long-term growth performance and tissue accretion of pigs inoculated with PEDV or PDCoV. Therefore, our objective was to determine the effect of PEDV or PDCoV infection on growth performance and tissue accretion over 42 d following inoculation. A total of 75 Choice Genetics Large White Pureline barrows and gilts (BW = 10.81 ± 0.81 kg) at approximately 2 wk post-wean and naïve for PEDV and PDCoV were selected. Pigs were allotted based on BW and sex, stratified across 3 treatments with 8 pens per treatment. Treatments were: 1) Control ( = 8); 2) PEDV inoculated ( = 8); and 3) PDCoV inoculated ( = 8). On day post inoculation (dpi) 2, 5, 7, and 14 pigs were euthanized for tissue collection and analyses from these tissues are discussed elsewhere. Pen feed intake and BW were recorded on dpi 2, 5, 7, and weekly thereafter until dpi 42. On 1 designated pig per pen, initial and final body composition was determined using dual-energy X-ray absorptiometry (DXA) and tissue accretion rates were calculated over 6 wk test period. Peak PEDV infection was noted at 3 dpi compared with 4 dpi for PDCoV pigs as determined by fecal swab quantitative real-time PCR (RT-PCR). Control pigs remained negative for PEDV and PDCoV throughout the experiment. Overall, Control and PDCoV pigs did not differ in ADG, ADFI or G:F ( > 0.05). Compared to Control and PDCoV pigs, the overall 42 d ADFI was reduced in the challenged PEDV pigs ( < 0.05) by 19 and 27%, respectively. PEDV did not significantly reduce the overall ADG or G:F compared with Control and PDCoV pigs; however, the biggest reduction in ADG and ADFI for PEDV pigs was within 14 dpi compared to the Control pigs ( < 0.05). Whole body tissue accretion was altered due to PED, with fat, lean, protein, and bone mineral accretion reductions by 24, 20, 21, and 42%, respectively ( < 0.05) compared with Control pigs. Overall, nursery pig performance was greatly impacted by PEDV challenge. Surprisingly, the PDCoV challenge did not negatively influence nursery pig performance. This study provides further insight into the longitudinal impact swine enteric coronaviruses have on growing pigs.

The largest outbreak of highly pathogenic avian Influenza A virus (HPAIV) infection in U.S. history began in December 2014 resulting in the euthanasia of millions of birds and collateral economic consequences to the U.S. poultry industry. We describe 2 cases of H5N2 HPAIV infection in laying hens in Iowa. Following a sharp increase in mortality with minimal clinical signs, 15 dead birds, from 2 unrelated farms, were submitted to the Iowa State University Veterinary Diagnostic Laboratory. Common lesions included diffuse edema and multifocal hemorrhage of the comb, catarrhal exudate in the oropharynx, and multifocal tracheal hemorrhage. Less common lesions included epicardial petechiae, splenic hemorrhage, and pancreatic necrosis. Influenza A virus nucleoprotein was detected by immunohistochemistry in multiple cell types including ependymal cells, the choroid plexus, neurons, respiratory epithelium and macrophages in the lung, cardiac myocytes, endothelial cells, necrotic foci in the spleen, Kupffer cells in the liver, and necrotic acinar cells in the pancreas. Real-time polymerase chain reaction and sequencing confirmed H5N2 HPAIV with molecular characteristics similar to other contemporary U.S. H5N2 HPAIVs in both cases., (© 2016 The Author(s).)

Porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED) are two diseases costly to the U.S. swine industry. The objective of this study was to determine the impact of PRRS virus and PED virus, alone or in combination, on growth performance, feed efficiency, and digestibility in grower pigs. Forty-two gilts (16 ± 0.98 kg BW) naïve for PRRS and PED were selected and allocated to 1 of 4 treatments. Treatments included 1) a control, 2) PRRS virus infected, 3) PED virus infected, and 4) PRRS+PED coinfection (PRP). Pigs in treatments 2 and 4 were inoculated with a live field strain of PRRS virus via intramuscular and intranasal routes at 0 d after inoculation (dpi). Treatments 3 and 4 were orally inoculated with a cloned PED virus at 15 dpi. Infection with PRRS virus was confirmed by quantitative PCR and seroconversion. Infection with PED virus was confirmed with PCR. Control pigs remained PRRS and PED virus negative throughout the study. All pigs were offered, ad libitum, a standard diet with free access to water. During the test period, PRRS reduced ADG and ADFI by 30 and 26%, respectively ( < 0.05), compared with control pigs, whereas PRP decreased ADG, ADFI, and G:F by 45, 30, and 23%, respectively ( < 0.05). Additional reductions in ADG and G:F were detected in PRP pigs compared with singular PED or PRRS treatments (33 and 16%, respectively). The impact of PED, alone or in combination, on performance (15-21 dpi) reduced ADG (0.66 vs. 0.35 vs. 0.20 kg/d; < 0.01), ADFI (1.22 vs. 0.88 vs. 0.67 kg/d; = 0.003), and G:F (0.54 vs. 0.39 vs. 0.31; = 0.001) compared with control pigs. Compared with control pigs, PRRS infection did not reduce apparent total tract digestibility (ATTD) of nutrients and energy. However, PED infection, alone or in combination, decreased ATTD of DM and energy by 8 and 12%, respectively ( < 0.05). Compared with control pigs, PRP reduced N and OM ATTD by 13 and 3%, respectively ( < 0.05). No significant differences in apparent ileal digestibility (AID) were detected between virus challenges. However, Lys AID tended to be reduced in both PED treatments compared with the control (10 and 12%; = 0.095). Altogether, PRRS reduced growth but did not alter digestibility. Pigs challenged with PED and, to a greater extent, the coinfection of PED and PRRS viruses had reduced ADG, ADFI, G:F, and ATTD of nutrients and energy.

The objective of this study was to determine if intestinal function and integrity is altered due to porcine reproductive and respiratory syndrome (PRRS) virus and porcine epidemic diarrhea (PED) virus infection in growing pigs. Forty-two gilts (16.8 ± 0.6 kg BW), naïve for PRRS and PED, were selected and randomly assigned to 1 of 4 treatments: 1) a control (CON; = 6), 2) PRRS virus challenge only (PRRS; = 12), 3) PED virus challenge only (; = 12), or 4) coinfection of PRRS + PED viruses (PRP; = 12). Treatments 2 and 4 were inoculated with a live field strain of PRRS virus on d 0 after inoculation. Treatments 3 and 4 were inoculated with PED virus on 14 d after inoculation (dpi) and all pigs were euthanized 7 d later (21 dpi). Infection with PRRS virus was determined by viremia and seroconversion. Fecal quantitative PCR was used to confirm PED virus infection. Control pigs remained PRRS and PED virus negative throughout the study. Compared with the CON, intestinal morphology was unaffected by PRRS. As expected, PED and PRP treatments resulted in duodenum, jejunum, and ileum villus atrophy compared with the CON treatment ( < 0.01). Ex vivo transepithelial electrical resistance (TER) did not differ between CON and PRRS pigs (P < 0.05) but was reduced by 40% in PED alone ( < 0.01). Interestingly, TER was increased ( < 0.01) in the PRP pigs. Active transport of glucose was increased in PRRS pigs over CON pigs ( < 0.01), whereas PED had pigs increased ( < 0.01) active glutamine transport over the CON pigs. Jejunum GLUT2 mRNA abundance and sucrase, maltase, and Na+/K+ adenosine triphosphatase activities tended to be increased in PRRS pigs compared with CON pigs ( < 0.06). The jejunum AA transporter, SLC6A14, and mucin 2 mRNA abundance tended to be increased in PED-only pigs ( < 0.10). These data suggest that PRRS infection supports a higher affinity for glucose uptake, whereas PED favors glutamine uptake. Interestingly, digestive machinery during PED challenge remained intact. Altogether, PED but not PRRS challenges alter intestinal morphology and integrity in growing pigs.