Next-generation sequencing in veterinary medicine: how can the massive amount of information arising from high-throughput technologies improve diagnosis, control, and management of infectious diseases?

Detection of Mycobacteria in Arabian camels and antimycobacterial potential of Moringa oleifera

The World Health Organization gave great attention to Mycobacterium tuberculosis, especially its zoonotic impact. Dromedary camels in Arabian countries are of great importance, as well as awareness of production and health. Little was known about the occurrence of M. tuberculosis among Arabian camels. Out of 88 samples were collected from necropsied male camels aged 5-6.5 years after the slaughter process resident in Cairo abattoir. Isolation of Mycobacteria was achieved on Middle Brook 7H10 agar with special supplements, and then the suspected colonies were assessed by their specific aspects. Lungs and lymph nodes were processed for histopathology. Molecular characterization was carried out by both conventional amplification (Mycobacterium bovis mpb70, M. tuberculosis- Pan Mycobacterium 16S rRNA) tracked by sanger sequencing; and bacterial 16S rRNA V3-V4 hypervariable region was amplified then it was followed by Mi-seq Ilumina. Moringa oliefera's oil was analyzed by GC-MS. The antimycobacterial potential of M. oliefera was conducted by In vitro tetrazolium microplate assay (TEMA). In silico docking mode of action and prediction were studied. Mycobacterium was isolated from 9.4% (3/32) of the lung samples and 2.4% (1/41) of the recovered lymph node samples. The isolated strains had ideal culture characteristics of Mycobacterium. Sanger sequencing identified the M. tuberculosis variant bovis DRC-EG-CAMEL PQ036932. Mi-seq Illumina revealed abundant sequence readings belonging to ancestral Actinobacteria and Micromonosporaceae. In vitro testing showed that the Moringa oleifera methanol leaf extract had antimicrobial activity with MIC ranging from 7.8 to 32 µg/ml, and the seed oil showed inhibitory effects at 50% (v/v) (P value < 0.05). In silico docking of ferulic acid against M. tuberculosis variant bovis ribosomal protein S1 showed an affinity score of - 5.95 kcal/mol with one hydrogen bond. While squalene lipoprotein LprF exhibited a professional affinity score of - 6.11 kcal/mol with seventeen hydrophobic π-interactions. Mycobacterium tuberculosis variant bovis is measured to prevail in the Arabian camels. However, this study provided a detailed examination of Mycobacterium in camels, offering practical solutions to combat this pathogen and mitigate the effects of infection or zoonotic impacts on other animals and humans. Sanger sequencing is more recommended for Mycobacterium identification. Moringa oliefera's potential anti-mycobacterial effect through either leaves or oil might be achieved for humans and animals as a different strategy for medicinal plants' role. It might be a new insight into the struggle and the adverse effects of tuberculosis. In the upcoming research, therapeutic compounds could be separated from M. oliefera.

Integrated analysis of miRNA and mRNA expression profiles in the bursa of Fabricius of specific pathogen-free chickens infected with avian reticuloendotheliosis virus strain SNV

Reticuloendotheliosis virus (REV) is a gamma retrovirus that can cause immunosuppression, dwarf syndrome and acute reticulocytoma in poultry. The molecular mechanism by which REV infection leads to immunosuppression and tumorigenesis is poorly understood. In this study, we elucidated the regulatory network of miRNA-mRNA and the major signaling pathways involved in REV-SNV infection. Therefore, we used the spleen necrosis virus (SNV) model of REV to inoculate one-day-old specific pathogen-free (SPF) chickens and then performed global miRNA and mRNA expression profiling by conducting high-throughput sequencing of 18 bursa of Fabricius samples collected at 7, 14, and 21 dpi. In total, 213 differentially expressed miRNAs (DEMs) and 3311 differentially expressed genes (DEGs) were identified. In the miRNA-mRNA network constructed based on the association analysis of these DEMs and DEGs, 1376 negatively correlated miRNA-mRNA pairs were identified; among them, 82 pairs were identified at 7 dpi, 203 pairs were identified at 14 dpi, and 873 pairs were identified at 21 dpi. Moreover, the results of the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of the mRNAs in the network revealed greater enrichment of immune-related pathways, such as the immune system, signal transduction, cell growth and death, and signaling molecules and interactions. We confirmed the selected immune-related DEMs and their DEGs by conducting quantitative RT-PCR (qRT-PCR) analysis. These findings increased our understanding of the interactions of miRNAs and their target genes during infection with REV-SNV, and contributed to the understanding of host-virus interactions.

Advances in Whole Genome Sequencing: Methods, Tools, and Applications in Population Genomics

With the rapid advancement of high-throughput sequencing technologies, whole genome sequencing (WGS) has emerged as a crucial tool for studying genetic variation and population structure. Utilizing population genomics tools to analyze resequencing data allows for the effective integration of selection signals with population history, precise estimation of effective population size, historical population trends, and structural insights, along with the identification of specific genetic loci and variations. This paper reviews current whole genome sequencing technologies, detailing primary research methods, relevant software, and their advantages and limitations within population genomics. The goal is to examine the application and progress of resequencing technologies in this field and to consider future developments, including deep learning models and machine learning algorithms, which promise to enhance analytical methodologies and drive further advancements in population genomics.

Complete Genome Sequences of Avian Metapneumovirus Subtype B Vaccine Strains from Brazil

Avian metapneumovirus (aMPV) causes a highly contagious upper respiratory and reproductive disease in chickens, turkeys, and ducks. Here, complete genome sequences of aMPV-B vaccine strains BR/1890/E1/19 (PL21, Nemovac; Boehringer Ingelheim Animal Health, Brazil) and BR/1891/E2/19 (1062; Hipraviar, France) were sequenced and compared with the pathogenic field strain VCO3/60616.

The increasing relevance of immunobiology within a connected animal science curriculum

Modern technological agriculture emerged in the 20th century and has expanded into a global enterprise occupying approximately 38% of the Earth's land area and accounting for over 40% of the world's workforce. The United Nations Food and Agriculture Organization estimates that to feed a world population of 9-billion people in 2050 will require an almost doubling of overall food production, including meat, dairy, and egg production over 2010 levels. However, our collective ability to meet this demand cannot be taken for granted. Despite many successes, global agricultural systems now face multiple unprecedented challenges including a dearth of new treatments for livestock diseases. The discovery of antibiotics led to a complacency now reflected in a dependency on exogenous antimicrobials and a growing threat of antimicrobial resistance. Developments within the field of immunobiology had led to significant breakthroughs in understanding of human health and disease. However, despite over 60% of infectious diseases being zoonotic in nature and nonhuman animals acting as an important disease reservoir, research in livestock immunobiology has not been as resourced. As a direct result, recalcitrant animal diseases continue to threaten sustainability of animal production systems, security of the food chain and human health. It is within the context of collective One Health action that ambitious innovation in the connectivity of animal science undergraduate curricula is urgently required, specifically to include threshold concepts in immunobiology. Fostering transformative learning is critical to equip future generations of animal scientists with the knowledge and interdisciplinary skills to counter these existential challenges of our time.

Functional evaluation of LTR-derived lncRNAs in porcine oocytes and zygotes with RNA-seq and small RNA-seq

Long noncoding RNAs (lncRNAs) are increasingly being recognized as modulators of early embryonic development in mammals. However, they are seldom investigated in pigs. Here, to annotate full-length RNA transcripts, we performed annotation using a newly developed computational pipeline—an RNA-seq and small RNA-seq combined strategy—using our previously obtained RNA-seq and small RNA-seq data from porcine oocytes and zygotes. As evidenced by the length comparison, the frequency of the core promoter, and the polyadenylation signal motifs, the transcripts appear to be full-length. Furthermore, our strategy allowed the identification of a large number of endogenous retrovirus-associated lncRNAs (ERV-lncRNAs) and found that some of them were highly expressed in porcine zygotes, as compared to oocytes. Through the knockdown strategy, two ERV-lncRNAs (TCONS_00035465 and TCONS_00031520) were identified as playing potential roles in the early embryo development of pigs, laying a foundation for future research.

Mexican Strains of Anaplasma marginale: A First Comparative Genomics and Phylogeographic Analysis

The One Health approach looks after animal welfare and demands constant monitoring of the strains that circulate globally to prevent outbreaks. Anaplasma marginale is the etiologic agent of bovine anaplasmosis and is endemic worldwide. This study aimed to analyze, for the first time, the genetic diversity of seven Mexican strains of A. marginale and their relationship with other strains reported. The main features of A. marginale were obtained by characterizing all 24 genomes reported so far. Genetic diversity and phylogeography were analyzed by characterizing the msp1a gene and 5′-UTR microsatellite sequences and constructing a phylogenetic tree with 540 concatenated genes of the core genome. The Mexican strains show 15 different repeat sequences in six MSP1a structures and have phylogeographic relationships with strains from North America, South America, and Asia, which confirms they are highly variable. Based on our results, we encourage the performance of genome sequencing of A. marginale strains to obtain a high assembly level of molecular markers and the performance of extensive phylogeographic analysis. Undoubtedly, genomic surveillance helps build a picture of how a pathogen changes and evolves in geographical regions. However, we cannot discard the study of relationships pathogens establish with ticks and how they have co-evolved to establish themselves as a successful transmission system.

Microbiome Research as an Effective Driver of Success Stories in Agrifood Systems – A Selection of Case Studies

Increasing knowledge of the microbiome has led to significant advancements in the agrifood system. Case studies based on microbiome applications have been reported worldwide and, in this review, we have selected 14 success stories that showcase the importance of microbiome research in advancing the agrifood system. The selected case studies describe products, methodologies, applications, tools, and processes that created an economic and societal impact. Additionally, they cover a broad range of fields within the agrifood chain: the management of diseases and putative pathogens; the use of microorganism as soil fertilizers and plant strengtheners; the investigation of the microbial dynamics occurring during food fermentation; the presence of microorganisms and/or genes associated with hazards for animal and human health (e.g., mycotoxins, spoilage agents, or pathogens) in feeds, foods, and their processing environments; applications to improve HACCP systems; and the identification of novel probiotics and prebiotics to improve the animal gut microbiome or to prevent chronic non-communicable diseases in humans (e.g., obesity complications). The microbiomes of soil, plants, and animals are pivotal for ensuring human and environmental health and this review highlights the impact that microbiome applications have with this regard.

Challenges and Solutions to Viral Diseases of Finfish in Marine Aquaculture

Aquaculture is the fastest food-producing sector in the world, accounting for one-third of global food production. As is the case with all intensive farming systems, increase in infectious diseases has adversely impacted the growth of marine fish farming worldwide. Viral diseases cause high economic losses in marine aquaculture. We provide an overview of the major challenges limiting the control and prevention of viral diseases in marine fish farming, as well as highlight potential solutions. The major challenges include increase in the number of emerging viral diseases, wild reservoirs, migratory species, anthropogenic activities, limitations in diagnostic tools and expertise, transportation of virus contaminated ballast water, and international trade. The proposed solutions to these problems include developing biosecurity policies at global and national levels, implementation of biosecurity measures, vaccine development, use of antiviral drugs and probiotics to combat viral infections, selective breeding of disease-resistant fish, use of improved diagnostic tools, disease surveillance, as well as promoting the use of good husbandry and management practices. A multifaceted approach combining several control strategies would provide more effective long-lasting solutions to reduction in viral infections in marine aquaculture than using a single disease control approach like vaccination alone.

Bovine Abortions Revisited-Enhancing Abortion Diagnostics by 16S rDNA Amplicon Sequencing and Fluorescence in situ Hybridization

Abortion in cattle causes significant economic losses for cattle farmers worldwide. The diversity of abortifacients makes abortion diagnostics a complex and challenging discipline that additionally is restrained by time and economy. Microbial culture has traditionally been an important method for the identification of bacterial and mycotic abortifacients. However, it comes with the inherent bias of favoring the easy-to-culture species, e.g., those that do not require cell culture, pre-enrichment, a variety of selective growth media, or different oxygen levels for in vitro growth. Molecular methods such as polymerase chain reaction (PCR) and next-generation sequencing have been established as alternatives to traditional microbial culturing methods in several diagnostic fields including abortion diagnostics. Fluorescence in situ hybridization (FISH), a bridging microscopy technique that combines molecular accuracy with culture independence, and spatial resolution of the pathogen-lesion relation, is also gaining influence in several diagnostic fields. In this study, real-time quantitative PCR (qPCR), 16S rDNA amplicon sequencing, and FISH were applied separately and in combination in order to (i) identify potentially abortifacient bacteria without the bias of culturability, (ii) increase the diagnostic rate using combined molecular methods, (iii) investigate the presence of the difficult-to-culture zoonotic agents Coxiella burnetii, Chlamydia spp., and Leptospira spp. in bovine abortions in Denmark. Tissues from 162 aborted or stillborn bovine fetuses and placentas submitted for routine diagnostics were screened for pathogenic bacteria using 16S rDNA amplicon sequencing. Lesion association of fungal elements, as well as of selection of bacterial abortifacients, was assessed using specific FISH assays. The presence of Chlamydia spp. and chlamydia-like organisms was assessed using qPCR. The study focused on bacterial and fungal abortifacients, because Danish cattle is free from most viral abortifacients. The 16S rDNA amplicon sequencing-guided FISH approach was suitable for enhancing abortion diagnostics, i.e., the diagnostic rate for cases with tissue lesions (n = 115) was increased from 46 to 53% when compared to routine diagnostic methods. Identification of Bacillus licheniformis, Escherichia coli, and Trueperella pyogenes accounted for the majority of additional cases with an established etiology. No evidence for emerging or epizootic bacterial pathogens was found. The difficult-to-culture abortifacients were either not detected or not identified as abortifacients.

Sensitive universal detection of blood parasites by selective pathogen-DNA enrichment and deep amplicon sequencing

BACKGROUND

Targeted amplicon deep sequencing (TADS) has enabled characterization of diverse bacterial communities, yet the application of TADS to communities of parasites has been relatively slow to advance. The greatest obstacle to this has been the genetic diversity of parasitic agents, which include helminths, protozoa, arthropods, and some acanthocephalans. Meanwhile, universal amplification of conserved loci from all parasites without amplifying host DNA has proven challenging. Pan-eukaryotic PCRs preferentially amplify the more abundant host DNA, obscuring parasite-derived reads following TADS. Flaherty et al. (2018) described a pan-parasitic TADS method involving amplification of eukaryotic 18S rDNA regions possessing restriction sites only in vertebrates. Using this method, host DNA in total DNA extracts could be selectively digested prior to PCR using restriction enzymes, thereby increasing the number of parasite-derived reads obtained following NGS. This approach showed promise though was only as sensitive as conventional PCR.

RESULTS

Here, we expand on this work by designing a second set of pan-eukaryotic primers flanking the priming sites already described, enabling nested PCR amplification of the established 18S rDNA target. This nested approach facilitated introduction of a second restriction digestion between the first and second PCR, reducing the proportional mass of amplifiable host-derived DNA while increasing the number of PCR amplification cycles. We applied this method to blood specimens containing Babesia, Plasmodium, various kinetoplastids, and filarial nematodes and confirmed its limit of detection (LOD) to be approximately 10-fold lower than previously described, falling within the range of most qPCR methods.

CONCLUSIONS

The assay detects and differentiates the major malaria parasites of humans, along with several other clinically important blood parasites. This represents an important step towards a TADS-based universal parasite diagnostic (UPDx) test with a sufficient LOD for routine applications. Video Abstract.

Increased viral read counts and metagenomic full genome characterization of porcine astrovirus 4 and Posavirus 1 in sows in a swine farm with unexplained neonatal piglet diarrhea

Neonatal diarrhea in piglets may cause major losses in affected pig herds. The present study used random high-throughput RNA sequencing (metagenomic next generation sequencing, mNGS) to investigate the virome of sows from a farm with persistent neonatal piglet diarrhea in comparison to two control farms without diarrhea problems. A variety of known swine gastrointestinal viruses was detected in the control farms as well as in the problem farm (Mamastrovirus, Enterovirus, Picobirnavirus, Posavirus 1, Kobuvirus, Proprismacovirus). A substantial increase in normalized viral read counts was observed in the affected farm compared to the control farms. The increase was attributable to a single viral species in each of the sampled sows (porcine astrovirus 4 and Posavirus 1). The complete genomes of a porcine astrovirus 4 and two co-infecting Posavirus 1 were de novo assembled and characterized. The 6734 nt single-stranded RNA genome of porcine astrovirus 4 (PoAstV-4) strain Belgium/2019 contains three overlapping open reading frames (nonstructural protein 1ab, nonstructural protein 1a, capsid protein). Posavirus 1 strains Belgium/01/2019 and Belgium/02/2019 have a 9814 nt single-stranded positive-sense RNA genome encoding a single open reading frame (polyprotein precursor) containing the five expected Picornavirales-conserved protein domains. The study highlights the potential of mNGS workflows to study unexplained neonatal diarrhea in piglets and contributes to the scarce availability of both PoAstV-4 and Posavirus-1 whole genome sequences from Western Europe.

Recent Advances in the Diagnosis of Classical Swine Fever and Future Perspectives

Classical swine fever (CSF) is a highly contagious viral disease of pigs, including wild boar. It is regarded as one of the major problems in the pig industry as it is still endemic in many regions of the world and has the potential to cause devastating epidemics, particularly in countries free of the disease. Rapid and reliable diagnosis is of utmost importance in the control of CSF. Since clinical presentations of CSF are highly variable and may be confused with other viral diseases in pigs, laboratory diagnosis is indispensable for an unambiguous diagnosis. On an international level, well-established diagnostic tests of CSF such as virus isolation, fluorescent antibody test (FAT), antigen capture antibody enzyme-linked immunosorbent assay (ELISA), reverse-transcription polymerase chain reaction (RT-PCR), virus neutralization test (VNT), and antibody ELISA have been described in detail in the OIE Terrestrial Manual. However, improved CSF diagnostic methods or alternatives based on modern technologies have been developed in recent years. This review thus presents recent advances in the diagnosis of CSF and future perspectives.

Rapid, Unbiased PRRSV Strain Detection Using MinION Direct RNA Sequencing and Bioinformatics Tools

Prompt detection and effective control of porcine reproductive and respiratory syndrome virus (PRRSV) during outbreaks is important given its immense adverse impact on the swine industry. However, the diagnostic process can be challenging due to the high genetic diversity and high mutation rate of PRRSV. A diagnostic method that can provide more detailed genetic information about pathogens is urgently needed. In this study, we evaluated the ability of Oxford Nanopore MinION direct RNA sequencing to generate a PRRSV whole genome sequence and detect and discriminate virus at the strain-level. A nearly full length PRRSV genome was successfully generated from raw sequence reads, achieving an accuracy of 96% after consensus genome generation. Direct RNA sequencing reliably detected the PRRSV strain present with an accuracy of 99.9% using as few as 5 raw sequencing reads and successfully differentiated multiple co-infecting strains present in a sample. In addition, PRRSV strain information was obtained from clinical samples containing 10⁴ to 10⁶ viral copies or more within 6 hours of sequencing. Overall, direct viral RNA sequencing followed by bioinformatic analysis proves to be a promising approach for identification of the viral strain or strains involved in clinical infections, allowing for more precise prevention and control strategies during PRRSV outbreaks.

Sequencing of animal viruses: quality data assurance for NGS bioinformatics

BACKGROUND

Next generation sequencing (NGS) is becoming widely used among diagnostics and research laboratories, and nowadays it is applied to a variety of disciplines, including veterinary virology. The NGS workflow comprises several steps, namely sample processing, library preparation, sequencing and primary/secondary/tertiary bioinformatics (BI) analyses. The latter is constituted by a complex process extremely difficult to standardize, due to the variety of tools and metrics available. Thus, it is of the utmost importance to assess the comparability of results obtained through different methods and in different laboratories. To achieve this goal, we have organized a proficiency test focused on the bioinformatics components for the generation of complete genome sequences of salmonid rhabdoviruses.

METHODS

Three partners, that performed virus sequencing using different commercial library preparation kits and NGS platforms, gathered together and shared with each other 75 raw datasets which were analyzed separately by the participants to produce a consensus sequence according to their own bioinformatics pipeline. Results were then compared to highlight discrepancies, and a subset of inconsistencies were investigated more in detail.

RESULTS

In total, we observed 526 discrepancies, of which 39.5% were located at genome termini, 14.1% at intergenic regions and 46.4% at coding regions. Among these, 10 SNPs and 99 indels caused changes in the protein products. Overall reproducibility was 99.94%. Based on the analysis of a subset of inconsistencies investigated more in-depth, manual curation appeared the most critical step affecting sequence comparability, suggesting that the harmonization of this phase is crucial to obtain comparable results. The analysis of a calibrator sample allowed assessing BI accuracy, being 99.983%.

CONCLUSIONS

We demonstrated the applicability and the usefulness of BI proficiency testing to assure the quality of NGS data, and recommend a wider implementation of such exercises to guarantee sequence data uniformity among different virology laboratories.

Compartmentalized evolution of Bovine Viral Diarrhoea Virus type 2 in an immunotolerant persistently infected cow

Bovine viral diarrhea virus (BVDV) is one of the most important pathogens of cattle worldwide. BVDV-1 is widely distributed in Italy, while BVDV-2 has been detected occasionally. BVDV can be classified in two biotypes, cytopathic (CP) or noncytopathic (NCP). The characteristic of the virus is linked with the infection of a pregnant dam with a NCP strain: due to viral establishment before maturation of the fetal immune system the calf remains persistently infected (PI) and immunotolerant to the infecting BVDV strain. Thanks to their immunotolerance, PI animals represent a unique model to study the viral distribution and compartmentalization in absence of immunoresponse in vivo. In the present study, NGS sequencing was used to characterize the BVDV2 viral strain infecting a PI calf and to describe the viral quasispecies in tissues. Even if the consensus sequences obtained by all the samples were highly similar, quasispecies was described evaluating the presence and the frequency of variants among all the sequencing reads in each tissue. The results suggest a high heterogeneity of the infecting viral strain suggesting viral compartmentalization. The quasispecies analysis highlights the complex dynamics of viral population structure and can increase the knowledge about viral evolution in BVDV-2 persistently infected animals.

Transformation of animal genomics by next-generation sequencing technologies: a decade of challenges and their impact on genetic architecture

For more than a quarter of a century, sequencing technologies from Sanger's method to next-generation high-throughput techniques have provided fascinating opportunities in the life sciences. The continuing upward trajectory of sequencing technologies will improve livestock research and expedite the development of various new genomic and technological studies with farm animals. The use of high-throughput technologies in livestock research has increased interest in metagenomics, epigenetics, genome-wide association studies, and identification of single nucleotide polymorphisms and copy number variations. Such studies are beginning to provide revolutionary insights into biological and evolutionary processes. Farm animals, such as cattle, swine, and horses, have played a dual role as economically and agriculturally important animals as well as biomedical research models. The first part of this study explores the current state of sequencing methods, many of which are already used in animal genomic studies, and the second part summarizes the state of cattle, swine, horse, and chicken genome sequencing and illustrates its achievements during the last few years. Finally, we describe several high-throughput sequencing approaches for the improved detection of known, unknown, and emerging infectious agents, leading to better diagnosis of infectious diseases. The insights from viral metagenomics and the advancement of next-generation sequencing will strongly support specific and efficient vaccine development and provide strategies for controlling infectious disease transmission among animal populations and/or between animals and humans. However, prospective sequencing technologies will require further research and in-field testing before reaching the marketplace.

Veterinary parasitology teaching at London - Meeting the 'Day-One Competency' needs of new veterinarians

Over the past four decades, there has been an exponential increase in veterinary parasitology knowledge, coinciding with the advent of molecular biology in research. Therefore, it is unrealistic for teachers to expect students to graduate with an encyclopaedic knowledge of the subject. As a result, a new curriculum was introduced at The Royal Veterinary College (University of London) in 2007, designed to meet the needs of our new graduates, i.e. RCVS Day-One Competences. The aims of this curriculum are, inter alia, to ensure that new graduates have an up-to-date body of core knowledge and are able to apply such knowledge and newly-acquired information to scientific and clinical problem-solving. Veterinary parasitology is taught primarily in Year 2, following a brief introduction in Year 1; clinical aspects are covered in Year 3, with original research projects undertaken in Years 4 and 5. Parasitology is taught in parallel with other subjects, enabling both horizontal and vertical integration. Core material is provided in lectures supplemented by directed learning (DL) in small groups and interactive, clinical scenario-based practical classes. Student learning is supported by Moodle 3.2 (Virtual Learning Environment [VLE], RVC Learn) which provides access to an on-line study guide (annotated using Adobe Reader), PowerPoint presentations with synchronized lecturer commentary (Echo Active Learning Platform [ALP]), detailed feedback for DL and practical classes, parasite 'potcasts' and CAL packages, and a Clinical Skills Centre. A parasitology textbook has also been published recently to support courses taught at the College. Assessment of student learning is achieved using a variety of written formats (essay, problem-solving questions [PSQ], multiple choice questions [MCQ] and extended matching questions [EMQ]), integrated oral examinations and objective structured clinical examinations (OSCEs).

Translating Big Data into Smart Data for Veterinary Epidemiology

The increasing availability and complexity of data has led to new opportunities and challenges in veterinary epidemiology around how to translate abundant, diverse, and rapidly growing “big” data into meaningful insights for animal health. Big data analytics are used to understand health risks and minimize the impact of adverse animal health issues through identifying high-risk populations, combining data or processes acting at multiple scales through epidemiological modeling approaches, and harnessing high velocity data to monitor animal health trends and detect emerging health threats. The advent of big data requires the incorporation of new skills into veterinary epidemiology training, including, for example, machine learning and coding, to prepare a new generation of scientists and practitioners to engage with big data. Establishing pipelines to analyze big data in near real-time is the next step for progressing from simply having “big data” to create “smart data,” with the objective of improving understanding of health risks, effectiveness of management and policy decisions, and ultimately preventing or at least minimizing the impact of adverse animal health issues.

The Challenges and Advances in Diagnosis of Vector-Borne Diseases: Where Do We Stand?

Vector-borne diseases (VBD) are of major importance to human and animal health. In recent years, VBD have been emerging or re-emerging in many geographical areas, alarming new disease threats and economic losses. The precise diagnosis of many of these diseases still remains a major challenge because of the lack of comprehensive data available on accurate and reliable diagnostic methods. Here, we conducted a systematic and in-depth review of the former, current, and upcoming techniques employed for the diagnosis of VBD.

The utility of diversity profiling using Illumina 18S rRNA gene amplicon deep sequencing to detect and discriminate Toxoplasma gondii among the cyst-forming coccidia

Next-generation sequencing (NGS) has the capacity to screen a single DNA sample and detect pathogen DNA from thousands of host DNA sequence reads, making it a versatile and informative tool for investigation of pathogens in diseased animals. The technique is effective and labor saving in the initial identification of pathogens, and will complement conventional diagnostic tests to associate the candidate pathogen with a disease process. In this report, we investigated the utility of the diversity profiling NGS approach using Illumina small subunit ribosomal RNA (18S rRNA) gene amplicon deep sequencing to detect Toxoplasma gondii in previously confirmed cases of toxoplasmosis. We then tested the diagnostic approach with species-specific PCR genotyping, histopathology and immunohistochemistry of toxoplasmosis in a Risso's dolphin (Grampus griseus) to systematically characterise the disease and associate causality. We show that the Euk7A/Euk570R primer set targeting the V1-V3 hypervariable region of the 18S rRNA gene can be used as a species-specific assay for cyst-forming coccidia and discriminate T. gondii. Overall, the approach is cost-effective and improves diagnostic decision support by narrowing the differential diagnosis list with more certainty than was previously possible. Furthermore, it supplements the limitations of cryptic protozoan morphology and surpasses the need for species-specific PCR primer combinations.

Next-generation sequencing shows West Nile virus quasispecies diversification after a single passage in a carrion crow (Corvus corone) in vivo infection model

West Nile virus (WNV) occurs as a population of genetic variants (quasispecies) infecting a single animal. Previous low-resolution viral genetic diversity estimates in sampled wild birds and mosquitoes, and in multiple-passage adaptation studies in vivo or in cell culture, suggest that WNV genetic diversification is mostly limited to the mosquito vector. This study investigated genetic diversification of WNV in avian hosts during a single passage using next-generation sequencing. Wild-captured carrion crows were subcutaneously infected using a clonal Middle-East WNV. Blood samples were collected 2 and 4 days post-infection. A reverse-transcription (RT)-PCR approach was used to amplify the WNV genome directly from serum samples prior to next-generation sequencing resulting in an average depth of at least 700 ×  in each sample. Appropriate controls were sequenced to discriminate biologically relevant low-frequency variants from experimentally introduced errors. The WNV populations in the wild crows showed significant diversification away from the inoculum virus quasispecies structure. By contrast, WNV populations in intracerebrally infected day-old chickens did not diversify from that of the inoculum. Where previous studies concluded that WNV genetic diversification is only experimentally demonstrated in its permissive insect vector species, we have experimentally shown significant diversification of WNV populations in a wild bird reservoir species.

Standing of nucleic acid testing strategies in veterinary diagnosis laboratories to uncover Mycobacterium tuberculosis complex members

Nucleic acid testing (NAT) designate any molecular approach used for the detection, identification, and characterization of pathogenic microorganisms, enabling the rapid, specific, and sensitive diagnostic of infectious diseases, such as tuberculosis. These assays have been widely used since the 90s of the last century in human clinical laboratories and, subsequently, also in veterinary diagnostics. Most NAT strategies are based in the polymerase chain reaction (PCR) and its several enhancements and variations. From the conventional PCR, real-time PCR and its combinations, isothermal DNA amplification, to the nanotechnologies, here we review how the NAT assays have been applied to decipher if and which member of the Mycobacterium tuberculosis complex is present in a clinical sample. Recent advances in DNA sequencing also brought new challenges and have made possible to generate rapidly and at a low cost, large amounts of sequence data. This revolution with the high-throughput sequencing (HTS) technologies makes whole genome sequencing (WGS) and metagenomics the trendiest NAT strategies, today. The ranking of NAT techniques in the field of clinical diagnostics is rising, and we provide a SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis with our view of the use of molecular diagnostics for detecting tuberculosis in veterinary laboratories, notwithstanding the gold standard being still the classical culture of the agent. The complementary use of both classical and molecular diagnostics approaches is recommended to speed the diagnostic, enabling a fast decision by competent authorities and rapid tackling of the disease.