Iowa State University Veterinary Diagnostic Research Articles

PSIX-26 Effectiveness of mineral supplementation during range grazing on mineral status in ewes

Abstract Mineral supplementation in the intermountain west region of the US may be necessary for maintenance of healthy flocks since important trace minerals are deficient in this region. However, rough terrain can make mineral supplementation challenging. The objective of this study was to evaluate the trace mineral status of ewes on range. We hypothesized that ewes with access to a mineral supplement would have decreased risk of mineral deficiency. In this study, ewes (n = 59) grazed four summer pastures on Cedar Mountain near Cedar City, Utah. Ewes between the ages of 1 and 6 yr of age were stratified by initial body weight (BW) = 87 kg ± 13 kg and breed [black face (BLF; Suffolk) and white face breeds (WF; Targhee, Rambouillet, and their crosses)] into two treatment groups 1) trace mineral supplement ad libitum (TRT; n = 7 BLF and 23 WF) or 2) no mineral supplement (CON; n = 15 BLF and 14 WF). All ewes received a diet of mixed alfalfa and triticale hay without mineral supplementation 30 d before the trial began. A SmartFeed (C-lock Inc.) was used to track individual animal mineral intake. Plasma samples were collected via jugular venipuncture at d 0, 34, 77, and 116. A clinical veterinarian from Utah State University performed liver biopsies at d 0 and 116 on a subset of ewes (n = 10). After the grazing season, plasma and liver samples were sent to the Iowa State University Veterinary Diagnostic Laboratory for analysis of Cu, Mn, Se, and Zn. The mixed procedure of SAS was used to analyze plasma mineral content with day as a repeated measure and individual ID as a random variable. The Glimmix procedure of SAS was used to analyze liver mineral content. Plasma Cu and Se increased (P ≤ 0.05) by day in all ewes throughout the grazing season. No differences related to treatment or breed (P > 0.10) were observed for plasma Cu or Se concentrations. Plasma Mn and Zn decreased (P < 0.0001) by 1.5 ppb and 0.4 ppm, respectively, between d 0 and 116 with no treatment effect (P > 0.10). BLF ewes had 0.3 ppm (P = 0.01) greater plasma Mn concentrations than WF ewes, with no difference (P = 0.6) observed due to treatment. Hepatic Cu and Se increased (P ≤ 0.05) by 114 ppm and 1 ppm, respectively, between d 0 and 116. Hepatic Mn concentrations did not differ (P > 0.10) by day or treatment. Hepatic Zn concentrations tended to increase by day (P = 0.07), 23 ppm between d 0 and 116. CON ewes had 28 ppm greater (P = 0.04) hepatic Zn concentrations than TRT ewes. Additional research is warranted to understand why CON had greater hepatic Zn concentrations than TRT, which may indicate that diverse rangeland forages may provide sufficient concentrations for sheep production in summer months.

Reverse zoonosis of the 2022–2023 human seasonal H3N2 detected in swine

The Iowa State University Veterinary Diagnostic Laboratory detected nineteen human-to-swine reverse zoonoses of the 2022–2023 human seasonal H3N2 between November 2022 and November 2023. Cases from seven U.S. locations were detected: 3 Colorado, 1 Illinois, 1 Indiana, 2 Missouri, 7 North Carolina, 1 Ohio, and 1 Pennsylvania. One additional case was detected in Mexico and two cases were identified from Chile. Case samples were comprised of 4 nasal swabs and 15 oral fluids. Virus was successfully isolated from two of four nasal swab samples, but isolation from oral fluids was unsuccessful. The swine detections of H3 human viruses were classified to one of two human-seasonal H3 clades, 3C.2a1b.2a.2b and 3C.2a1b.2a.2a.1. Phylogenetic inference indicated at minimum 7 reverse zoonotic events occurred, with possible swine-to-swine transmission following the initial spillover. Twelve neuraminidase genes were sequenced, and nine were classified as human-seasonal H3N2 lineage: the remaining were endemic swine IAV NA genes from the N2.2002B, N2.1998, or the N1.Classical lineage, suggesting reassortment. The two viral isolates obtained from nasal swab samples were sequenced and were entirely human-lineage viruses. Seven swine samples with human seasonal H3 were sequenced and revealed co-detections with H1 1A.3.3.3 (gamma), with internal gene segments from both the triple reassortant internal gene (TRIG) and pandemic 2009 lineages. Serologic investigation of samples from swine production systems provided evidence for infection with human seasonal H3N2. One farm in the United States and four farms in Mexico had concurrent virologic evidence. The swine-isolated 3C.2a1b.2a.2b H3N2 was antigenically distinct from endemic 1990.4.A, 2010.1, and 2010.2 swine H3N2 lineages, but retained antigenic similarity to a recent human seasonal H3N2 (A/Darwin/6/2021). Pigs experimentally inoculated with a representative isolate demonstrated replication in the nose and lungs and minimal to mild macroscopic and microscopic lung lesions, but primary pigs did not transmit the virus to indirect contacts. If sustained in the pig population, this human seasonal H3 would represent the first new lineage detected in pigs the 2020 decade and present an emerging threat to swine health and production.

Distribution trends of bovine Anaplasma marginale in Iowa, based upon veterinary diagnostic lab submissions from 2017-2022

Anaplasma marginale is the common etiological agent of bovine anaplasmosis. Infection results in erythrocyte de­struction leading to the clinical signs of anemia, hypoxia, abortion, jaundice and sudden death. Cattle that survive this acute phase or have lower levels of initial bacteremia become chronic, persistent carriers. Carrier animals serve as reser­voirs for the organism and allow infection to spread via me­chanical or biological vectors, to susceptible herdmates. The objective of this study was to report the distribution trends of A. marginale positive test results during a 5-year period in Iowa. This study evaluated Iowa State University Veterinary Diagnostic Lab (ISU VDL) testing results from bovine cases submitted from January 1, 2017 to January 1, 2022, for molecu­lar and serological detection of all stages of anaplasmosis. Cattle residing in Iowa with positive results for PCR or com­petitive ELISA were included in the analysis. The state was divided into 4 geographical districts (1 = northeast, 2 = south­east, 3 = southwest, and 4 = northwest) and the number of pos­itive tests in each district was determined. Total positive tests by district included: northeast 282; southeast 277; southwest 223; northwest 281. Disease spatial analysis mapping, based upon geographic longitude and latitude location of herds with positive diagnostic tests, illustrate progressive disease expan­sion from the southern counties of Iowa, near the Missouri border, into the northern parts of Iowa. These results suggest that A. marginale has developed a widespread distribution across the state of Iowa.

100 Evaluating the effect of liver copper concentration on vaccine response in lightweight dairy-beef steers

Abstract Dairy-beef crossbred calves often face greater copper (Cu) exposure than native beef calves, which may impact their response to vaccines. To investigate this, 28 weaned dairy-beef steers (90.25 ± 1.28 kg; ~8 wk old) were enrolled in a study to determine the effect of Cu status on the antibody response to vaccine. Steers were stratified by body weight (BW) and assigned to one of two dietary treatments: low Cu (no supplemental Cu) and high Cu (supplementing 20 mg Cu/kg DM). Steers were housed in pens of six to eight animals for 82 d before d 0 of the vaccination period to create distinct liver Cu groupings. Seven days before initial vaccine dose, liver biopsies were collected, and steers were grouped into low (n = 13) and high (n = 15) Cu treatments. Liver Cu for low Cu averaged 291 ± 24 mg/kg DM (range 240 to 376 mg/kg DM) and for high Cu averaged 665 ± 23 mg Cu/kg liver DM (range 519 to 893 mg/kg DM). All calves were vaccinated on d 0 and boostered 21 d later with Bovilis Vista 5 SQ (Merck Animal Health, Rahway, NJ) and an ovalbumin vaccine. Blood and BW were collected on these days and again on d 49 to end the study. Serum antibody titers for BRSV, BHV1, BVDV1, and BVDV2 were analyzed by the Iowa State University Veterinary Diagnostic Laboratory (Ames, IA). Response to ovalbumin vaccination was determined using an ELISA. Plasma Cu concentrations were determined on d 0, 21, and 49 via ICP-OES. Ovalbumin antibodies were determined by calculating the ratio of each sample to a positive control. Titers, ovalbumin response, and plasma Cu data from d 0, 21, and 49 were analyzed using the Mixed procedure of SAS 9.4 (Cary, NC) with the fixed effect of Cu treatment and day as repeated. Plasma Cu decreased across days (P = 0.0008). Given both treatments had adequate liver Cu, it is unsurprising plasma Cu did not differ by treatment (P = 0.2; 1.02 and 1.07 mg Cu/L for low and high Cu, respectively). Antibodies for BRSV, BHV1, and BVDV2 increased across days (P < 0.0001), but there were no differences by treatment (P ≥ 0.12). Ovalbumin antibodies were affected by treatment by day (P = 0.04), where high Cu had greater response to ovalbumin than low Cu on d 21, but by d 49 ovalbumin antibodies were similar between Cu treatments. These results suggest excessive liver Cu concentration may not affect response to vaccination in dairy-beef steers; however, more research is needed to determine the effects of increased liver Cu concentration on oxidative stress and immune system function.

Detection and disease diagnosis trends (2017–2022) for Streptococcus suis, Glaesserella parasuis, Mycoplasma hyorhinis, Actinobacillus suis and Mycoplasma hyosynoviae at Iowa State University Veterinary Diagnostic Laboratory

BackgroundAccurate 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.ResultsS. 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.ConclusionsResults 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.

Case report: Diagnostic findings of bovine neurological cases at the Iowa State University Veterinary Diagnostic Laboratory between January 2017 and May 2021

This study reviews the Iowa State University Veterinary Diagnostic Laboratory (ISU-VDL) computer records of bovine neurological cases submitted from January 2017 to May 2021. There were 236 cases diagnosed as follows: listeriosis (83), polioencephalomalacia (44), thrombomeningoencephalitis (23), miscellaneous bacteria (22), lead toxicosis (21), nitrate toxicosis (18), urea toxicosis (9), nervous coccidiosis (5), hypomagnesemia (5), sodium toxicosis (3), rabies (1), herpesvirus type 6 (1), and epsilon toxin from Clostridium perfringens type D (1). Most histories did not provide specific descriptions of the type of neurological signs, which could better target diagnostic investigation. However, each condition had specific peculiarities relevant from a post-mortem diagnostic perspective. For listeriosis, confirmation of Listeria monocytogenes using IHC was considered superior to bacterial culture, with 16/19 (84%) positive by IHC compared to 23/59 (38.9%) of cases positive by culture. In 44/83 (53.0%) of cases, histopathological examination mentioned that cerebellum and cerebrum were unremarkable, implying that without submission of the entire brain, particularly brain stem and obex, listeriosis cannot be ruled out. In 44 cases histologically diagnosed as polioencephalomalacia, when ultraviolet light (Wood’s lamp) was performed, it revealed multifocal areas of apple-green autofluorescence in 13/21 (61.9%) of brains, indicating that false negatives can occur with this technique. A substantial number of submissions were toxicoses that required specific sample types to confirm a diagnosis. For lead, whole blood, liver or kidney was necessary. For nitrate and urea toxicosis, appropriate samples were ocular fluid or the incriminating feed/water source. Confirmation of sodium toxicosis relied on sodium analysis of brain tissue.

A survey of vitamin and trace mineral ranges for diagnostic lab reporting from conventionally raised swine

Objective: The purpose of this study was to survey the vitamin and mineral levels in various pig tissues at different phases of the life cycle. Materials and methods: Forty-eight healthy pigs of different stages of production were used for sampling of different tissues. Seven sows and a minimum of 10 animals from each phase of production (suckling, nursery, and finishing) were selected for sampling. A blood sample was collected via sterile venipuncture for serum vitamin and mineral analysis. After euthanasia, the diaphragm and liver were collected. Samples were submitted to the Iowa State University Veterinary Diagnostic Laboratory for analysis. Data were analyzed using SAS (version 9.4; SAS Institute Inc) and presented as minimum and maximum concentrations with standard error. The experimental unit was the animal. Results: Levels of vitamin A, vitamin E, copper, zinc, selenium, iron, and manganese were higher in liver tissues than in serum and diaphragm tissues. Diaphragm muscle had similar levels of phosphorus as the liver tissue. Serum had similar levels of calcium as the liver tissue. Implications: These data provide a sampling of vitamin and mineral levels present in tissues and serum of commercial pigs and suggests that vitamin and mineral levels differ between sampling sites.

Use of the ISU FLUture multisequence identity tool for rapid interpretation of swine influenza A virus sequences in the United States.

Rapid and reliable identification of the hemagglutinin (HA) and neuraminidase (NA) genetic clades of an influenza A virus (IAV) sequence from swine can inform control measures and multivalent vaccine composition. Current approaches to genetically characterize HA or NA sequences are based on nucleotide similarity or phylogenetic analyses. Public databases exist to acquire IAV genetic sequences for comparison, but personnel at the diagnostic or production level have difficulty in adequately updating and maintaining relevant sequence datasets for IAV in swine. Further, phylogenetic analyses are time intensive, and inference drawn from these methods is impacted by input sequence data and associated metadata. We describe here the use of the IAV multisequence identity tool as an integrated public webpage located on the Iowa State University Veterinary Diagnostic Laboratory (ISU-VDL) FLUture website: https://influenza.cvm.iastate.edu/. The multisequence identity tool uses sequence data derived from IAV-positive cases sequenced at the ISU-VDL, employs a BLAST algorithm that identifies sequences that are genetically similar to submitted query sequences, and presents a tabulation and visualization of the most genetically similar IAV sequence and associated metadata from the FLUture database. Our tool removes bioinformatic barriers and allows clients, veterinarians, and researchers to rapidly classify and identify IAV sequences similar to their own sequences to augment interpretation of results.

Salmonella enterica serovar Brandenburg abortions in dairy cattle.

Two separate late-term abortion outbreaks in Jersey heifers in July 2020 and December 2020 were investigated by the Iowa State University Veterinary Diagnostic Laboratory. We evaluated 3 whole fetuses and 11 sets of fresh and formalin-fixed fetal tissues during the course of the outbreaks. The late-term abortions were first identified at a heifer development site and subsequently observed at the dairy farm. Aborted fetuses had moderate-to-marked postmortem autolysis with no gross lesions identified. Observed clinical signs in cows at the dairy farm ranged from intermittent loose stools to acute post-abortion pyrexia and reduced feed intake. Routine histopathology and reproductive bacterial culture revealed acute, suppurative placentitis with moderate-to-heavy growth of Salmonella spp. group B from stomach contents, liver, placenta, and heifer fecal contents. Serotyping identified Salmonella enterica subsp. enterica serovar Brandenburg in all 14 fresh tissue cases, as well as individual and pooled heifer feces. Whole-genome sequencing analysis revealed that all isolates belonged to ST type 873 and possessed typhoid toxin genes, several fimbrial gene clusters, type III secretion system genes, and several pathogenicity islands. Abortions caused by Salmonella Brandenburg have not been reported previously in dairy cattle in the United States, to our knowledge.

Prevalence, Mechanism, Genetic Diversity, and Cross-Resistance Patterns of Methicillin-Resistant Staphylococcus Isolated from Companion Animal Clinical Samples Submitted to a Veterinary Diagnostic Laboratory in the Midwestern United States.

Methicillin-resistant Staphylococcus (MRS) is a leading cause of skin and soft tissue infections in companion animals, with limited treatment options available due to the frequent cross-resistance of MRS to other antibiotics. In this study, we report the prevalence, species distribution, genetic diversity, resistance mechanism and cross-resistance patterns of MRS isolated from companion animal (mostly dog and cat) clinical cases submitted to Iowa State University Veterinary Diagnostic Laboratory (ISU VDL) between 2012 and 2019. The majority of isolates were identified as Staphylococcus pseudintermedius (68.3%; 2379/3482) and coagulase-negative Staphylococcus (CoNS) (24.6%; 857/3482), of which 23.9% and 40.5% were phenotypically resistant to methicillin, respectively. Cross resistance to other β-lactams (and to a lesser extent to non-β-lactams) was common in both methicillin-resistant S. pseudintermedius (MRSP) and CoNS (MRCoNS), especially when oxacillin MIC was ≥4 μg/mL (vs. ≥0.5–<4 μg/mL). The PBP2a protein was detected by agglutination in 94.6% (521/551) MRSP and 64.3% (146/227) MRCoNS. A further analysis of 31 PBP2a-negative MRS isolates (all but one MRCoNS) indicated that 11 were mecA gene-positive while 20 were negative for mecA and other mec genes by PCR. The resistance to last-resort anti-staphylococcal human drugs (e.g., tigecycline, linezolid, vancomycin) among the MRS tested was none to very low. Even though genotyping indicated an overall high level of genetic diversity (87 unique PFGE patterns and 20 MLST types) among a subset of MRSP isolates tested (n = 106), certain genotypes were detected from epidemiologically connected cases at the same or different time points, suggesting persistence and/or nosocomial transmission. These results indicate a relatively high prevalence of MRS from companion animals in the Midwestern US; therefore, it is important to perform routine susceptibility testing of Staphylococcus in veterinary clinical settings for the selection of appropriate antimicrobial therapy.

Characterization of a 2016-2017 Human Seasonal H3 Influenza A Virus Spillover Now Endemic to U.S. Swine.

ABSTRACTIn 2017, the Iowa State University Veterinary Diagnostic Laboratory detected a reverse-zoonotic transmission of a human seasonal H3 influenza A virus into swine (IAV-S) in Oklahoma. Pairwise comparison between the recently characterized human seasonal H3 IAV-S (H3.2010.2) hemagglutinin (HA) sequences detected in swine and the most similar 2016–2017 human seasonal H3 revealed 99.9% nucleotide identity. To elucidate the origin of H3.2010.2 IAV-S, 45 HA and 27 neuraminidase (NA) sequences from 2017 to 2020 as well as 11 whole-genome sequences (WGS) were genetically characterized. Time to most recent common human ancestor was estimated between August and September 2016. The N2 NA was of human origin in all but one strain from diagnostic submissions with NA sequences, and the internal gene segments from WGS consisted of matrix genes originating from the 2009 pandemic H1N1 and another 5 internal genes of triple reassortant swine origin (TTTTPT). Pigs experimentally infected with H3.2010.2 demonstrated efficient nasal shedding and replication in the lungs, mild pneumonia, and minimal microscopic lung lesions and transmitted the virus to indirect contact swine. Antigenically, H3.2010.2 viruses were closer to a human seasonal vaccine strain, A/Hong Kong/4801/2014, than to the H3.2010.1 human seasonal H3 viruses detected in swine in 2012. This was the second sustained transmission of a human seasonal IAV into swine from the 2010 decade after H3.2010.1. Monitoring the spillover and detection of novel IAV from humans to swine may help vaccine antigen selection and could impact pandemic preparedness.IMPORTANCE H3.2010.2 is a new phylogenetic clade of H3N2 circulating in swine that became established after the spillover of a human seasonal H3N2 from the 2016–2017 influenza season. The novel H3.2010.2 transmitted and adapted to the swine host and demonstrated reassortment with internal genes from strains endemic to pigs, but it maintained human-like HA and NA. It is genetically and antigenically distinct from the H3.2010.1 H3N2 introduced earlier in the 2010 decade. Human seasonal IAV spillovers into swine become established in the population through adaptation and sustained transmission and contribute to the genetic and antigenic diversity of IAV circulating in swine. Continued IAV surveillance is necessary to detect emergence of novel strains in swine and assist with vaccine antigen selection to improve the ability to prevent respiratory disease in swine as well as the risk of zoonotic transmission.

Acute hemorrhage and death in calves following chlorophacinone exposure.

Three calves were submitted to the Iowa State University Veterinary Diagnostic Laboratory for diagnostic evaluation following an abrupt increase in morbidity and mortality in a calf herd associated with epistaxis and widespread hemorrhage. Each of the submitted calves had moderate-to-severe hemorrhage within various tissues and body cavities, including the thymus, subcutaneous region of the neck, mediastinum, lungs, pericardial sac, heart, spleen, perirenal fat, urinary bladder, and skeletal muscle, including the diaphragm. An anticoagulant rodenticide screen was performed on the livers of each calf. Significant concentrations of chlorophacinone were detected at 4.2, 3.6, and 2.9 ppm in liver. Multiple piles and an open pail of white powdery material were present within the facility in which the calves were housed and were identified as the sources of chlorophacinone. Acute hemorrhage and death occurred in fourteen 1.5-mo-old, crossbred calves following ingestion of the vitamin K antagonist chlorophacinone.

Streptococcus gallolyticus and Bacterial Endocarditis in Swine, United States, 2015-2020.

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.

289 Serum Trace Minerals in Late Gestation Sows at Variable Risk for Pelvic Organ Prolapse

Abstract Within the last decade, pelvic organ prolapse (POP) resulting in sow mortality has become an increasing concern for the U.S. swine industry, contributing approximately 21% of all sow deaths. While little is known regarding the etiology preceding POP in sows, many have proposed an association with vitamin and trace minerals abundance to POP incidence. We tested the hypothesis that sows differing in POP risk would have differences in serum trace minerals and vitamins. A perineal scoring (PS) system (PS1 - presumed low risk; PS2 - presumed moderate risk; and PS3 - presumed high risk) to assess risk for POP during late gestation was used to score 213 individual sows. Blood was collected from sows of two different farms during late gestation (days 105–115) that scored a PS3 (n = 20) and a parity matched sow scored as PS 1 (n = 16). Subsequently, 1.5, 0.8, and 23.1% of sows scored as PS1, PS2, or PS3, respectively, experienced POP. Serum was analyzed at the Iowa State University Veterinary Diagnostic Lab for trace mineral content (Calcium, Copper, Iron, Potassium, Magnesium, Manganese, Molybdenum, Phosphorus, Selenium, and Zinc). Additionally, vitamin E was evaluated in serum via GC-MS. Differences (P &amp;lt; 0.05) in copper, potassium, molybdenum, phosphorus, and selenium was observed between farms. Further a PS x Farm interaction (P = 0.06) was observed for serum copper abundance which across all farms was 12% less (P &amp;lt; 0.04) in PS3 compared to PS1 sows. No impact on serum vitamin E was observed between PS sows. These data demonstrate sows with greater POP risk may have potential differences in serum factors although these data also underscore the importance of measuring vitamin and mineral quantities in a tissue specific manner. This project was supported by the National Pork Board and the Foundation for Food and Agriculture Research.

Disease diagnostic coding to facilitate evidence-based medicine: current and future perspectives.

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.

Utilizing technology to enhance laboratory-client interaction while encouraging best behavior.

As client interactions with veterinary diagnostic laboratories have evolved, so have client expectations: faster results, enhanced accessibility to cases, and more seamless data transfer from the laboratory database; all of these factors have encouraged the evolution of diagnostic laboratory systems. This evolution started with 24-h access to laboratory results via the web, yet data quality remained at the mercy of the person filling out the form. If bad (incomplete) information was flowing in, then the data coming out was equally bad (incomplete or inconsistent). By designing a web-based system integrated into our existing reporting platform, the Iowa State University Veterinary Diagnostic Laboratory (ISU-VDL) set out to improve the quality of submission data by including the premises identification number (PIN) and obtaining consistent location data, all while presenting to the client an easy-to-use interface. Efforts continued by incentivizing the use of this tool and client submission practices. As clients transitioned, data have become more complete, resulting in easier queries and an improved ability to leverage the diagnostic data. To further enhance the client experience, a streamlined daily reporting summary was designed to communicate laboratory results succinctly. The use of these web-based tools had a positive impact on the quality and consistency of the diagnostic data. As new ideas develop, the ISU-VDL strives to foster continuous improvement and positively impact the clients' experience.

Modeling regional disease spread over time using a dynamic spatio-temporal model – With an application to porcine epidemic diarrhea virus data in Iowa, US

Regional surveillance is important for detecting the incursion of new pathogens and informing disease monitoring and control programs. Modeling disease distribution over time can provide insight into the development of more efficient regional surveillance approaches. Herein we propose a Bayesian spatio-temporal model to describe the distribution of porcine epidemic diarrhea virus (PEDV) in Iowa USA. Model parameters are estimated through a Bayesian spatio-temporal model approach which can account for missing values. For illustration, we apply the proposed model to PEDV test results from the Iowa State University Veterinary Diagnostic Laboratory (ISU-VDL). A simulation study carried out to evaluate the model showed that the proposed model captured the pattern of PEDV distribution and its spatio-temporal dependence.

Cases of high mortality in cull sows and feeder pigs associated with Streptococcus equi subsp. zooepidemicus septicemia.

Investigations of 2 cases of high mortality in cull sows and feeder pigs from a buying station in Ohio and cull sows at an abattoir in Tennessee were conducted at the Iowa State University Veterinary Diagnostic Laboratory. The animals were presented as weak, lethargic, and some with high fever. Rapidly escalating mortality was reported to be as high as 30-50% within groups at the buying station over 8-10 d, and 30-40% over 5-7 d at the abattoir. Splenomegaly and red lymph nodes were the most consistent macroscopic findings, with scant fibrinous polyserositis observed in one sow. The microscopic lesions of vasculitis, fibrin thrombi, fibrinosuppurative polyserositis, and intralesional bacteria were consistent with acute bacterial septicemia. Bacterial culture isolated Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) from multiple organs, including spleen, lung, and kidney. PCR tests were negative for African swine fever virus, classical swine fever virus, Erysipelothrix rhusiopathiae, porcine reproductive and respiratory syndrome virus, porcine circovirus 2, and Salmonella spp. Porcine circovirus 3 was inconsistently detected at low levels by PCR, with a lack of associated lesions. Next-generation sequencing identified S. zooepidemicus and porcine partetravirus in the serum sample of the feeder pig from the buying station. Phylogenetic analysis of the szP gene indicated that the S. zooepidemicus isolates from Ohio and Tennessee are in genotype VI. We conclude that the cause of these high mortality events in swine was S. zooepidemicus septicemia.

Detection of live attenuated influenza vaccine virus and evidence of reassortment in the U.S. swine population.

Influenza vaccines historically have been multivalent, whole virus inactivated products. The first bivalent, intranasal, live attenuated influenza vaccine (LAIV; Ingelvac Provenza), with H1N1 and H3N2 subtypes, has been approved for use in swine. We investigated the LAIV hemagglutinin (HA) sequences in diagnostic cases submitted to the Iowa State University Veterinary Diagnostic Laboratory and potential vaccine virus reassortment with endemic influenza A virus (IAV) in swine. From January 3 to October 11, 2018, IAV HA sequences demonstrating 99.5-99.9% nucleotide homology to the H1 HA or 99.4-100% nucleotide homology to the H3 HA parental strains in the LAIV were detected in 58 of 1,116 (5.2%) porcine respiratory cases (H1 HA A/swine/Minnesota/37866/1999[H1N1; MN99]; H3 HA A/swine/Texas/4199-2/1998[H3N2; TX98]). Nine cases had co-detection of HA genes from LAIV and wild-type IAV in the same specimen. Thirty-five cases had associated epidemiologic information that indicated they were submitted from 11 states representing 31 individual sites and 17 production systems in the United States. Whole genome sequences from 11 cases and another subset of 2 plaque-purified IAV were included in our study. Ten whole genome sequences, including 1 plaque-purified IAV, contained at least one internal gene from endemic IAV detected within the past 3 y. Phylogenetic analysis of whole genome sequences indicated that reassortment occurred between vaccine virus and endemic field strains circulating in U.S. swine. Our data highlight the need and importance of continued IAV surveillance to detect emerging IAV with LAIV genes in the swine population.

Association between antimicrobial drug class for treatment and retreatment of bovine respiratory disease (BRD) and frequency of resistant BRD pathogen isolation from veterinary diagnostic laboratory samples.

Although 90% of BRD relapses are reported to receive retreatment with a different class of antimicrobial, studies examining the impact of antimicrobial selection (i.e. bactericidal or bacteriostatic) on retreatment outcomes and the emergence of antimicrobial resistance (AMR) are deficient in the published literature. This survey was conducted to determine the association between antimicrobial class selection for treatment and retreatment of BRD relapses on antimicrobial susceptibility of Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. Pathogens were isolated from samples submitted to the Iowa State University Veterinary Diagnostic Laboratory from January 2013 to December 2015. A total of 781 isolates with corresponding animal case histories, including treatment protocols, were included in the analysis. Original susceptibility testing of these isolates for ceftiofur, danofloxacin, enrofloxacin, florfenicol, oxytetracycline, spectinomycin, tilmicosin, and tulathromycin was performed using Clinical and Laboratory Standards Institute guidelines. Data were analyzed using a Bayesian approach to evaluate whether retreatment with antimicrobials of different mechanistic classes (bactericidal or bacteriostatic) increased the probability of resistant BRD pathogen isolation in calves. The posterior distribution we calculated suggests that an increased number of treatments is associated with a greater probability of isolates resistant to at least one antimicrobial. Furthermore, the frequency of resistant BRD bacterial isolates was greater with retreatment using antimicrobials of different mechanistic classes than retreatment with the same class. Specifically, treatment protocols using a bacteriostatic drug first followed by retreatment with a bactericidal drug were associated with a higher frequency of resistant BRD pathogen isolation. In particular, first treatment with tulathromycin (bacteriostatic) followed by ceftiofur (bactericidal) was associated with the highest probability of resistant M. haemolytica among all antimicrobial combinations. These observations suggest that consideration should be given to antimicrobial pharmacodynamics when selecting drugs for retreatment of BRD. However, prospective studies are needed to determine the clinical relevance to antimicrobial stewardship programs in livestock production systems.