Hiring intentions and remuneration of veterinary practitioners in western Canada.

All private veterinary practices in western Canada (N = 1333) were surveyed during the SARS-CoV-2 pandemic (January to November 2020) to generate data on the demographics of the profession, and to quantify past and present hiring intentions (demand) as well as remuneration for veterinary associates. The response rate was 39.5% (526/1333), 186 of which had hired at least one full- (FT) or part-time (PT) associate within the 12-month period preceding the completion of the survey. When extrapolated to the practices that did not respond (nonresponders), as many as 471 practices may have hired an associate within the previous 12 mo. The median (mean) annual remuneration paid to FT associates was $90 000 ($91 730). The median number of months it took to hire an associate did not vary by province (P = 0.52); however, it did vary by practice type (P <0.0001): companion animal practice, 3.0 mo; food animal practice, 8.0 mo; and mixed animal practice, 12.0 mo. At the time of the survey, 232 of the 526 (44.1%) responding practices were currently seeking to fill 281 vacancies, representing 274 full-time equivalents (FTE). If extrapolated to the nonresponders, the total number of vacant FTE positions could have been as high as 694. The median (mean) annual wage offered for a FT associate was $87 500 ($88 940), which did not differ by province (P = 0.14) or practice type (P = 0.22). The results of this study support anecdotal reports of a shortage of private veterinary practitioners in western Canada.

Intentions d'embauche et rémunération des vétérinaires praticiens dans l'Ouest canadien. Tous les cabinets vétérinaires privés de l'Ouest canadien (N = 1333) ont été interrogés pendant la pandémie de SARS-CoV-2 (janvier à novembre 2020) afin de générer des données sur la démographie de la profession et de quantifier les intentions d'embauche passées et présentes (demande) ainsi que rémunération des associés vétérinaires. Le taux de réponse était de 39,5 % (526/1333), dont 186 avaient embauché au moins un associé à temps plein (FT) ou à temps partiel (PT) au cours de la période de 12 mois précédant la fin de l'enquête. Lorsqu'ils sont extrapolés aux pratiques qui n'ont pas répondu (non-répondants), jusqu'à 471 pratiques peuvent avoir embauché un associé au cours des 12 derniers mois. La rémunération annuelle médiane (moyenne) versée aux associés de FT était de 90 000 $ (91 730 $). Le nombre de mois qu'il a fallu pour embaucher un associé ne variait pas selon la province (P = 0,52); cependant, elle variait selon le type de pratique (P <0,0001) : pratique des animaux de compagnie, 3,0 mois; pratique des animaux destinés à l'alimentation, 8,0 mois; et pratique animale mixte, 12,0 mois. Au moment de l'enquête, 232 des 526 cabinets répondants (44,1 %) cherchaient actuellement à pourvoir 281 postes vacants, représentant 274 équivalents temps plein (ETP). Si extrapolé aux non-répondants, le nombre total de postes vacants en ETP aurait pu atteindre 694. Le salaire annuel médian (moyen) offert pour un associé à temps plein était de 87 500 $ (88 940 $), ce qui ne différait pas selon la province (P = 0,14) ou type de pratique (P = 0,22). Les résultats de cette étude appuient les rapports anecdotiques d'une pénurie de vétérinaires praticiens privés dans l'Ouest canadien.(Traduit par Dr Serge Messier).

Demographic survey of private veterinary practices in western Canada.

A workforce survey of private veterinary practices in western Canada was conducted in 2020. Data were obtained on 526 practices (response rate = 39.5%) and 1445 individual veterinary practitioners. Overall, 68.4% of practitioners identified as female, with 4 times as many females as males comprising the youngest age cohorts (26 to 35 y) of the profession. The majority of practices (67.9%) were companion animal, followed by mixed animal (21.9%) and food animal (10.2%). Most females (77.2%) and males (57.8%) were engaged in companion animal practice, whereas 23.5% of males and 6.0% of females were food animal practitioners. During an average work week, practitioners devoted 77.4% of practice time to small animals, 15.1% to food animals, and 7.5% to equine animals. A greater proportion of males (75.2%) versus females (63.2%) worked on a full-time equivalent basis (P < 0.001). Whereas males were 1.7 times (95% CI = 1.3 to 2.3; P < 0.001) more likely to be practice owners than females, 54.5% of females were owners. Practice ownership was lower than in previous surveys, a trend that may have long-term implications with respect to the corporatization of the veterinary profession.

Enquête démographique sur les cabinets vétérinaires privés dans l'Ouest canadien. Une enquête sur la main-d'oeuvre des cabinets vétérinaires privés dans l'Ouest canadien a été menée en 2020. Des données ont été obtenues sur 526 cabinets (taux de réponse = 39,5 %) et 1445 praticiens vétérinaires individuels. Dans l'ensemble, 68,4 % des praticiens se sont identifiés comme des femmes, avec quatre fois plus de femmes que d'hommes parmi les cohortes d'âge les plus jeunes (26 à 35 ans) de la profession. La majorité des pratiques (67,9 %) étaient chez les animaux de compagnie, suivis des pratiques mixtes (21,9 %) et chez les animaux de rente (10,2 %). La plupart des femmes (77,2 %) et des hommes (57,8 %) travaillaient en pratique des animaux de compagnie, tandis que 23,5 % des hommes et 6,0 % des femmes étaient en pratique des animaux de rente. Au cours d'une semaine de travail moyenne, les praticiens ont consacré 77,4 % de leur temps de pratique aux petits animaux, 15,1 % aux animaux de rente et 7,5 % aux équidés. Une plus grande proportion d'hommes (75,2 %) que de femmes (63,2 %) travaillaient en équivalent temps plein (P < 0,001). Alors que les hommes étaient 1,7 fois (IC à 95 % = 1,3 à 2,3; P < 0,001) plus susceptibles d'être propriétaires d'un cabinet que les femmes, 54,5 % des femmes étaient propriétaires. La propriété de la pratique était plus faible que dans les enquêtes précédentes, une tendance qui peut avoir des implications à long terme en ce qui concerne la corporisation de la profession vétérinaire.(Traduit par Dr Serge Messier).

Depletion of pulmonary intravascular macrophages rescues inflammation-induced delayed neutrophil apoptosis in horses.

The objective of this study was to determine the effect of pulmonary intravascular macrophage depletion on systemic inflammation and ex vivo neutrophil apoptosis using an experimental model of intestinal ischemia and reperfusion injury in horses. Neutrophils were isolated before and after surgery from horses that were randomized to three treatment groups, namely, sham celiotomy (CEL, n = 4), intestinal ischemia and reperfusion (IR, n = 6), and intestinal ischemia and reperfusion with gadolinium chloride treatment to deplete pulmonary intravascular macrophages (PIMs, IRGC, n = 6). Neutrophil apoptosis was assessed with Annexin V and propidium iodide staining quantified with flow cytometry and caspase-3, caspase-8, and caspase-9 activities in neutrophil lysates. All horses experienced a systemic inflammatory response following surgery. Following surgery, ex vivo neutrophil apoptosis was significantly delayed after 12 or 24 h in culture, except in IRGC horses (12 h: CEL: P = 0.03, IR: P = 0.05, IRGC: P = 0.2; 24 h: CEL: P = 0.001, IR: P = 0.004, IRGC: P = 0.3). Caspase-3, caspase-8, and caspase-9 activities were significantly reduced in neutrophils isolated after surgery and cultured for 12 h in IR horses, but not in IRGC horses (IR caspase-3: P = 0.002, IR caspase-8: P = 0.002, IR caspase-9: P = 0.04). Serum TNF-α concentration was increased in IRGC horses for 6-18 h following jejunal ischemia. Following surgery, ex vivo equine neutrophil apoptosis was delayed via downregulation of caspase activity, which was ameliorated by PIM depletion potentially via upregulation of TNF-α.

A Bovine Enteric Mycobacterium Infection Model to Analyze Parenteral Vaccine-Induced Mucosal Immunity and Accelerate Vaccine Discovery.

Mycobacterial diseases of cattle are responsible for considerable production losses worldwide. In addition to their importance in animals, these infections offer a nuanced approach to understanding persistent mycobacterial infection in native host species. Mycobacteriumavium ssp. paratuberculosis (MAP) is an enteric pathogen that establishes a persistent, asymptomatic infection in the small intestine. Difficulty in reproducing infection in surrogate animal models and limited understanding of mucosal immune responses that control enteric infection in the natural host have been major barriers to MAP vaccine development. We previously developed a reproducible challenge model to establish a consistent MAP infection using surgically isolated intestinal segments prepared in neonatal calves. In the current study, we evaluated whether intestinal segments could be used to screen parenteral vaccines that alter mucosal immune responses to MAP infection. Using Silirum® - a commercial MAP bacterin - we demonstrate that intestinal segments provide a platform for assessing vaccine efficacy within a relatively rapid period of 28 days post-infection. Significant differences between vaccinates and non-vaccinates could be detected using quantitative metrics including bacterial burden in intestinal tissue, MAP shedding into the intestinal lumen, and vaccine-induced mucosal immune responses. Comparing vaccine-induced responses in mucosal leukocytes isolated from the site of enteric infection versus blood leukocytes revealed substantial inconsistences between these immune compartments. Moreover, parenteral vaccination with Silirum did not induce equal levels of protection throughout the small intestine. Significant control of MAP infection was observed in the continuous but not the discrete Peyer's patches. Analysis of these regional mucosal immune responses revealed novel correlates of immune protection associated with reduced infection that included an increased frequency of CD335+ innate lymphoid cells, and increased expression of IL21 and IL27. Thus, intestinal segments provide a novel model to accelerate vaccine screening and discovery by testing vaccines directly in the natural host and provides a unique opportunity to interrogate mucosal immune responses to mycobacterial infections.

Regional Dichotomy in Enteric Mucosal Immune Responses to a Persistent Mycobacterium avium ssp. paratuberculosis Infection.

Chronic enteric Mycobacterium avium ssp. paratuberculosis (MAP) infections are endemic in ruminants globally resulting in significant production losses. The mucosal immune responses occurring at the site of infection, specifically in Peyer's patches (PP), are not well-understood. The ruminant small intestine possesses two functionally distinct PPs. Discrete PPs function as mucosal immune induction sites and a single continuous PP, in the terminal small intestine, functions as a primary lymphoid tissue for B cell repertoire diversification. We investigated whether MAP infection of discrete vs. continuous PPs resulted in the induction of significantly different pathogen-specific immune responses and persistence of MAP infection. Surgically isolated intestinal segments in neonatal calves were used to target MAP infection to individual PPs. At 12 months post-infection, MAP persisted in continuous PP (n = 4), but was significantly reduced (p = 0.046) in discrete PP (n = 5). RNA-seq analysis revealed control of MAP infection in discrete PP was associated with extensive transcriptomic changes (1,707 differentially expressed genes) but MAP persistent in continuous PP elicited few host responses (4 differentially expressed genes). Cytokine gene expression in tissue and MAP-specific recall responses by mucosal immune cells isolated from PP, lamina propria and mesenteric lymph node revealed interleukin (IL)22 and IL27 as unique correlates of protection associated with decreased MAP infection in discrete PP. This study provides the first description of mucosal immune responses occurring in bovine discrete jejunal PPs and reveals that a significant reduction in MAP infection is associated with specific cytokine responses. Conversely, MAP infection persists in the continuous ileal PP with minimal perturbation of host immune responses. These data reveal a marked dichotomy in host-MAP interactions within the two functionally distinct PPs of the small intestine and identifies mucosal immune responses associated with the control of a mycobacterial infection in the natural host.

Role of toll-like receptor 4 and caspase-3, -8, and -9 in lipopolysaccharide-induced delay of apoptosis in equine neutrophils.

OBJECTIVE To evaluate the effect of lipopolysaccharide (LPS) on apoptosis of equine neutrophils in vitro. SAMPLE Venous blood samples from 40 adult horses. PROCEDURES Neutrophils were isolated from blood samples and cultured with or without LPS from Escherichia coli O55:B5 for 12 or 24 hours. Neutrophil apoptosis was assessed by use of cytologic examination, annexin V and propidium iodide staining quantified with flow cytometry, coincubation with inducers of intrinsic and extrinsic apoptosis or a toll-like receptor (TLR) 4 inhibitor, and measurement of caspase-3, -8, and -9 activities. RESULTS Treatment with LPS resulted in a significant delay in apoptosis after incubation for 12 and 24 hours (neutrophils from blood samples of 40 horses). There was a significant correlation between increases in LPS dose and decreases in apoptosis after incubation for 24 hours (3 experiments, each of which involved neutrophils obtained from the same 3 horses at 3 separate times). Caspase-9 activity, but not caspase-3 or -8 activity, was significantly reduced in LPS-treated neutrophils after incubation for 12 hours (neutrophils from blood samples of 17 horses). Treatment with a TLR4 inhibitor or intrinsic and extrinsic inducers of apoptosis prevented LPS-delayed apoptosis. CONCLUSIONS AND CLINICAL RELEVANCE LPS treatment delayed apoptosis of equine neutrophils in vitro for up to 24 hours in a dose-dependent manner by alteration of the intrinsic pathway of apoptosis and was dependent on TLR4 signaling. Increased neutrophil life span may contribute to the development of a systemic inflammatory response syndrome in endotoxemic horses.

Bistable expression of CsgD in Salmonella enterica serovar Typhimurium connects virulence to persistence.

Pathogenic bacteria often need to survive in the host and the environment, and it is not well understood how cells transition between these equally challenging situations. For the human and animal pathogen Salmonella enterica serovar Typhimurium, biofilm formation is correlated with persistence outside a host, but the connection to virulence is unknown. In this study, we analyzed multicellular-aggregate and planktonic-cell subpopulations that coexist when S. Typhimurium is grown under biofilm-inducing conditions. These cell types arise due to bistable expression of CsgD, the central biofilm regulator. Despite being exposed to the same stresses, the two cell subpopulations had 1,856 genes that were differentially expressed, as determined by transcriptome sequencing (RNA-seq). Aggregated cells displayed the characteristic gene expression of biofilms, whereas planktonic cells had enhanced expression of numerous virulence genes. Increased type three secretion synthesis in planktonic cells correlated with enhanced invasion of a human intestinal cell line and significantly increased virulence in mice compared to the aggregates. However, when the same groups of cells were exposed to desiccation, the aggregates survived better, and the competitive advantage of planktonic cells was lost. We hypothesize that CsgD-based differentiation is a form of bet hedging, with single cells primed for host cell invasion and aggregated cells adapted for persistence in the environment. This allows S. Typhimurium to spread the risks of transmission and ensures a smooth transition between the host and the environment.

Morphometric examination of the equine adult and foal lung.

To understand the mechanisms of airway inflammation associated with equine diseases such as Rhodococcus equi infection, we must identify baseline "normal" structural characteristics of the horse lung. To develop a detailed understanding of the morphology of the horse lung, we adapted and applied stereological methods to the lungs from healthy adult horses (N = 4) and 1-day (N = 5) and 30-day (N = 5) old foals. The left lung was fixed in situ by intrabronchial instillation of glutaraldehyde/paraformaldehyde fixative at 25 cm H2 O column and sampled using a fractionator design followed by embedding in glycol methacrylate. The lung was characterized into parenchyma and non-parenchyma, where median parenchymal density was 81.0% in 1-day-old foals, 84.4% in 30-day-old foals and 93.7% in adult lungs. The median volume density of alveolar airspace per lung was 45.9% in 1-day-old, 55.5% in 30-day and 66.9% in adult horse lungs. The median alveolar surface area increased with age, from 205.3 m(2) , 258.2 m(2) , and 629.9 m(2) in 1-day-old foals, 30-day-old foals, and adults, respectively. While the median alveolar surface density decreased with age, the mean linear intercept (mean free distance within acinar airspaces) increased with age. Alveolar surface area was greater than endothelial surface area within each lung. The ratio between alveolar and endothelial surface density remains unchanged with age. The median endothelium surface area was 106.2 m(2) in 1-day, 147.5 m(2) in 30-day, and 430 m(2) in adult lungs. The data suggest the foal lung is functionally developed and postnatal lung development and remodelling is driven by alveolar expansion paralleled with angiogenesis.

Failure of a VapA/CpG oligodeoxynucleotide vaccine to protect foals against experimental Rhocococcus equi pneumonia despite induction of VapA-specific antibody and interferon-γ response.

We evaluated the immunogenic and protective potential of a recombinant VapA/CpG oligodeoxynucleotide (ODN) 2395 vaccine in neonatal foals undergoing experimental Rhodococcus equi challenge. Foals (n = 8) were vaccinated by intramuscular injection on days 1 and 15 of the study; control foals (n = 7) received a phosphate-buffered saline (PBS) solution. All foals were challenged by intrabronchial administration of 5 × 106 R. equi 103⁺ on day 29. Bronchoalveolar lavages were done on days 15, 29, and 36 and total cell count, differential cell count, rVapA-stimulated cell proliferation and interferon (IFN)-γ mRNA expression determined. Clinical examination, complete blood (cell) counts, serology for VapA-specific antibodies, and culture of nasal and fecal swabs were done on days 1, 15, 29, 36, 43, and 50. Foals were humanely euthanized on day 50 and severity of pneumonia scored on a 4-point scale. Vaccination resulted in a significant increase in VapA-specific immunoglobulin (Ig) production, with total IgG and IgG(T) being increased by day 15. Expression of VapA-specific IFN-γ mRNA by BAL cells was increased in the vaccinated foals following challenge. Postmortem lung severity scores did not differ between groups. Two foals shed virulent R. equi in feces; however, real-time polymerase chain reaction (PCR) revealed the isolates to be different from the challenge strain.

Nous avons évalué le potentiel immunogène et protecteur d'un vaccin recombinant VapA/oligodéoxynucléotide CpG (ODN) 2395 chez des poulains nouveau-nés soumis à une infection défi par Rhodococcus equi. Les poulains (n = 8) étaient vaccinés par voie intramusculaire aux jours 1 et 15 de l'étude; les poulains témoins (n = 7) ont reçu une injection d'une solution de saline tamponnée (PBS). Tous les poulains ont été challengés par administration intra-bronchique de 5 × 106R. equi 103+ au jour 29. Des lavages broncho-alvéolaires (LBA) ont été effectués aux jours 15, 29 et 36 et on détermina le nombre total de cellules, un dénombrement cellulaire différentiel, la prolifération des cellules rVapA stimulées et l'expression d'ARNm de l'interféron (IFN)-γ. Un examen clinique, des comptages cellulaires sanguins complets, une analyse sérologique pour détecter les anticorps spécifiques contre VapA, et une culture d'écouvillons nasal et fécal ont été effectués aux jours 1, 15, 29, 36, 43 et 50. Les poulains ont été euthanasiés au jour 50 et la sévérité de la pneumonie notée sur une échelle de 4 points. La vaccination a causé une augmentation significative de la production d'immunoglobulines (Ig) spécifiquement dirigées contre VapA, les quantités totales d'IgG et d'IgG(T) ayant augmentées au jour 15. L'expression d'ARNm de l'IFN-γ spécifique au VapA par les cellules des LBA était augmentée chez les poulains vaccinés suite au challenge. Aucune différence ne fut notée dans les pointages de sévérité des lésions pulmonaires lors des examens post-mortem. Deux poulains excrétaient du R. equi virulent dans leurs fèces; toutefois, l'analyse par réaction d'amplification en chaîne par la polymérase (PCR) a démontré que ces isolats étaient différents de la souche utilisée pour le challenge.(Traduit par Docteur Serge Messier).

Localization of Bovine papillomavirus in equine sarcoids and inflammatory skin conditions of horses using laser microdissection and two forms of DNA amplification.

Equine sarcoids are the most common tumor of horses. Bovine papillomavirus (BPV) has been suggested as the cause of sarcoids. Studies have shown that BPV is present in swabs or biopsies from nonsarcoid-bearing equine skin. Skin biopsies from a variety of different conditions and normal skin from horses with no reported history of sarcoids were examined by polymerase chain reaction (PCR) for the presence of BPV, which was found in all different types of skin conditions as well as normal skin. Forty-one out of 86 skin biopsies from horses without sarcoids were found to contain BPV DNA. Laser microdissection, followed by DNA amplification through both PCR and isothermal loop-mediated amplification, was performed on these 41 biopsies and on 70 additional BPV-positive sarcoid biopsies to localize the virus. Location of BPV DNA was different between sarcoid and nonsarcoid groups. Nonsarcoid skin biopsies were more likely to have BPV within intact or inflamed epidermis than sarcoids (P = 0.016 and P = 0.007, respectively). Areas of inflammation within the dermis and epidermis were more likely to contain BPV than in noninflamed areas (P = 0.008 and P = 0.009, respectively). Bovine papillomavirus was also found in the epidermis of all types of sarcoids examined, more frequently in occult sarcoids than in fibroblastic and nodular types (P = 0.03 and P = 0.01, respectively). Results suggest that BPV is commonly found in normal and inflamed equine skin, and it is likely an important predisposing factor in the development of sarcoids.

Genes coding for virulence determinants of Campylobacter jejuni in human clinical and cattle isolates from Alberta, Canada, and their potential role in colonization of poultry.

Forty nine Campylobacter jejuni isolates from cattle feces collected from Alberta feedlots and 50 clinical C. jejuni isolates from people in Alberta were tested for the presence of 14 genes encoding putative virulence factors by PCR. These included genes implicated in adherence and colonization (flaC, cadF, docC, racR, jlpA, peb1, and dnaJ), invasion (virB11, ciaB, pldA, and iamA) and protection against harsh conditions (htrA, cbrA, and sodB). The genes examined were widely distributed in both the cattle fecal isolates and the human isolates. Of the isolates tested, 67% contained all of the genes except virB11. The cadF gene was found in 100% of the isolates tested. The presence or absence of virulence-associated genes was not associated with the ability of the organism to colonize birds. All of the C. jejuni isolates used to challenge birds were able to colonize the animals regardless of virulence gene profile. While some diversity in the profile of the occurrence of virulence-associated genes in C. jejuni exists, the distribution of these putative virulence-associated genes isolates from feedlot cattle feces and humans in Alberta was similar. In addition it was not possible to predict the ability of the selected isolates to colonize young chicks based on the presence of these genes coding for virulence determinants.

B-cell activating factor (BAFF) promotes CpG ODN-induced B cell activation and proliferation.

It is controversial whether naïve B cells are directly activated in response to TLR9 ligand, CpG ODN. Although bovine blood-derived CD21(+) B cells express TLR9 and proliferate in response to CpG in mixed-cell populations, purified bovine B cells do not proliferate significantly in response to CpG ODN, even when the B cell receptor is engaged. When co-cultured with CD14(+) myeloid cells and/or B-cell activating factor (BAFF), a cytokine produced by activated myeloid cells, there was a significant increase in CpG-specific B cell proliferation, and the number of large B cells in general or positive for CD25, all of which are markers for B cell activation. These data suggest that activated myeloid cells and BAFF prime B cells for significant CpG-specific activation. Understanding the signals required to mediate efficient CpG-induced, antigen-independent and T-cell independent activation of B cells has implications for polyclonal B cell activation and the development of autoimmune diseases.

Subcutaneous, but not intratracheal administration of the TLR9 agonist, CpG DNA transiently reduces parainfluenza-3 virus shedding in newborn lambs.

Synthetic oligodeoxynucleotides (ODN) containing CpG motifs signal through TLR9 and activate innate immunity resulting in protection against a variety of parasitic, bacterial and viral pathogens in mouse models. However, few studies have demonstrated protection in humans and large animals. In the present investigations, we evaluated protection by CpG ODN in a parainfluenza-3 (PI-3) virus infection in neonatal lambs. Subcutaneous (SC) injection of CpG ODN induced high levels of 2'5'-A synthetase and significantly reduced PI-3 virus shedding in newborn lambs. Furthermore, pre-treatment of newborn lambs with SC CpG ODN 2 days, but not 6 days prior to the virus challenge was protective. In contrast, intratracheal (IT) administration of CpG ODN induced 2'5'-A synthetase but had no significant impact on PI-3 virus shedding in nasal secretions. We conclude that a systemic administration of CpG ODN and the timing of the treatment are critical for the protection of neonatal lambs against a respiratory viral infection.

Epidemiology of equine sarcoids in horses in western Canada.

Sarcoids are the most common tumor of the equine skin but only 1 study describing the epidemiology of sarcoids in Canadian horses has been published. The records of 5 veterinary diagnostic laboratories in western Canada were searched to identify submissions of sarcoids from horses. The submission records and diagnostic reports of 802 separate submissions of equine sarcoids were reviewed for age, breed, and gender of the horse and the number, location, and clinical type of sarcoid. From these records, the 307 submissions to laboratories in Saskatchewan were compared to a reference group to test for breed and gender predisposition. Based on clinical history and lesion descriptions, 5 clinical types of sarcoids were identified. Horses of various ages and 23 equine breeds were affected; donkeys were over-represented. Polymerase chain reaction (PCR) for the bovine papillomavirus (BPV) DNA was performed on formalin-fixed paraffin-embedded tissues from a stratified subset of 96 of the different clinical types; BPV2 was present in 60 of 74 (81%) for which a PCR product was obtained. Unlike other areas in the world, in western Canada, equine sarcoids are most commonly associated with BPV type 2.

Immune responses of Asian elephants (Elephas maximus) to commercial tetanus toxoid vaccine.

Although captive elephants are commonly vaccinated annually against tetanus using commercially available tetanus toxoid vaccines marketed for use in horses and livestock, no data exists to prove that tetanus toxoid vaccination produces measurable antibody titers in elephants. An ELISA test was created to measure antibody responses to tetanus toxoid vaccinations in 22 Asian elephants ranging in age from 24 to 56 years (mean age 39 years) over a 7-month period. All animals had been previously vaccinated with tetanus toxoid vaccine, with the last booster administered 4 years before the start of the study. The great majority of elephants had titers prior to booster vaccination, and following revaccination all elephants demonstrated anamnestic increases in titers, indicating that this species does respond to tetanus vaccination. Surprisingly older animals mounted a significantly higher response to revaccination than did younger animals.

Salmonella enterica serovar enteritidis pathogenicity island 1 is not essential for but facilitates rapid systemic spread in chickens.

Salmonella enterica subsp. enterica serovar Enteritidis is a leading cause of human food-borne illness that is mainly associated with the consumption of contaminated poultry meat and eggs. To cause infection, S. Enteritidis is known to use two type III secretion systems, which are encoded on two salmonella pathogenicity islands, SPI-1 and SPI-2, the first of which is thought to play a major role in invasion and bacterial uptake. In order to study the role of SPI-1 in the colonization of chicken, we constructed deletion mutants affecting the complete SPI-1 region (40 kb) and the invG gene. Both DeltaSPI-1 and DeltainvG mutant strains were impaired in the secretion of SipD, a SPI-1 effector protein. In vitro analysis using polarized human intestinal epithelial cells (Caco-2) revealed that both mutant strains were less invasive than the wild-type strain. A similar observation was made when chicken cecal and small intestinal explants were coinfected with the wild-type and DeltaSPI-1 mutant strains. Oral challenge of 1-week-old chicken with the wild-type or DeltaSPI-1 strains demonstrated that there was no difference in chicken cecal colonization. However, systemic infection of the liver and spleen was delayed in birds that were challenged with the DeltaSPI-1 strain. These data demonstrate that SPI-1 facilitates systemic infection but is not essential for invasion and systemic spread of the organism in chickens.

Genomics-based molecular epidemiology of Campylobacter jejuni isolates from feedlot cattle and from people in Alberta, Canada.

Feedlot cattle in Alberta, Canada, have been identified as reservoirs for Campylobacter jejuni, an important human pathogen. Oligonucleotide DNA microarrays were used as a platform to compare C. jejuni isolates from feedlot cattle and human clinical cases from Alberta. Comparative genomic hybridization (CGH) analysis was performed on 87 isolates (46 bovine, 41 human) obtained within the same geographical regions and time frame. Thirteen CGH clusters were obtained based on overall comparative genomic profile similarity. Nine CGH clusters contained human and cattle isolates, three contained only human isolates, and one contained only cattle isolates. The study isolates clustered regardless of temporal or geographical frameworks. In addition, array genes (n = 1,399) were investigated on a gene-by-gene basis to see if any were unequally distributed between human and cattle sources or between clusters dominated by either human or cattle isolates ("human enriched" versus "cattle enriched"). Using Fisher's exact test with the Westfall and Young correction for these comparisons, a small number of differentially distributed genes were identified. Our findings suggest that feedlot cattle and human C. jejuni strains are very similar and may be endemic within Alberta. Further, the common distribution of human clinical and bovine C. jejuni isolates within the same genetically based clusters suggests that dynamic and important transmission routes between cattle and human populations may exist.

Prevalence and risk factor investigation of Campylobacter species in beef cattle feces from seven large commercial feedlots in Alberta, Canada.

This fecal prevalence study targeted cattle from 7 large (10,000 to > 40,000 head) commercial feedlots in Alberta as a means of establishing Campylobacter levels in cattle just prior to animals entering the food chain. Overall, 87% [95% confidence interval (CI) = 86-88] of 2776 fresh pen-floor fecal samples were culture positive for Campylobacter species, with prevalences ranging from 76% to 95% among the 7 feedlots. Campylobacter spp. prevalence was 88% (95% CI = 86-90) in the summer (n = 1376) and 86% (95% CI = 85-88) in the winter (n = 1400). In addition, 69% (95% CI = 66-71) of 1486 Campylobacter spp. positive samples were identified as Campylobacter jejuni using hippurate hydrolysis testing. Of those, 64% (95% CI = 58-70) of 277 and 70% (95% CI = 67-72) of 1209 Campylobacter isolates were identified as C. jejuni in winter and summer, respectively. After accounting for clustering within pen and feedlot, feedlot size and the number of days on feed were associated with Campylobacter spp. isolation rates. The high isolation rates of Campylobacter spp. and C. jejuni in feedlot cattle feces in this study suggest a potential role for feedlot cattle in the complex epidemiology of campylobacters in Alberta.

Seroprevalence and risk factors for infection with West Nile virus in Saskatchewan horses, 2003.

The primary objectives of this study were to determine the seroprevalence of West Nile virus (WNV) infection of horses in Saskatchewan in 2003 and to identify risk factors for the infection. Blood samples were collected in August and October from 212 horses in 20 herds in 5 geographic zones. After accounting for within-herd clustering, the proportion of horses that had been infected with WNV, as determined by IgG and IgM antibody response, was 55.7% (95% confidence interval, 44.9% to 65.8%). The proportion of antibody-positive horses differed among herds (0% to 100%) and across ecoregions (20% to 76%). Horses in southern ecoregions were more likely to have either IgM antibodies or IgG concentrations suggesting infection than were horses in northern ecoregions. The use of mosquito-control measures was associated with decreased risk. After accounting for ecoregion, there was no difference between recipients of an inactivated WNV vaccine and nonrecipients in the occurrence of antibodies reflecting natural infection.

Systemic innate immune responses following intrapulmonary delivery of CpG oligodeoxynucleotides in sheep.

Mucosal delivery of CpG oligodeoxynucleotide (ODN) in mice has been shown to induce potent innate immunostimulatory responses and protection against infection. We evaluated the efficacy of CpG ODN in stimulating systemic innate immune responses in sheep following delivery to the pulmonary mucosa. Intrapulmonary (IPM) administration of B-Class CpG ODN in saline induced transient systemic responses which included increased rectal temperatures, elevated serum 2'5'-A synthetase and haptoglobin concentrations. The ODN dose required to induce detectable systemic responses following IPM delivery could be reduced by approximately 80% if the CpG ODN was administered in 30% emulsigen instead of saline. Intrapulmonary B-Class CpG ODN formulated in 30% emulsigen produced similar effects when compared to those seen following SC injection. These responses were CpG ODN-specific since control GpC ODN did not induce any detectable response. Intrapulmonary administration of both B-Class and the newly described C-Class CpG ODN produced similar effects indicating that both classes of CpG ODN were comparably effective in stimulating innate immune system following mucosal delivery. Administration of CpG ODN directly into the lungs or delivery of CpG ODN via an intratracheal (IT) infusion also produced similar systemic responses. These observations support the conclusion that mucosal delivery of CpG ODN is an effective route for induction of systemic acute phase responses and antiviral effector molecules in large animals, and may be helpful in controlling systemic infections.