Presumptive metastatic leiomyosarcoma in a feedlot steer.

A 14-month-old feedlot steer was depressed and died while being examined. The gross post-mortem examination of the steer conducted at the feedlot identified numerous masses within the abdomen and thorax, including a large mass in the liver that eroded into the vena cava. Many masses in the lungs appeared to be the result of hematogenous distribution. Histologic examination of the masses confirmed the presence of neoplasia. Although the histologic appearance of the neoplasms was not typical of well-differentiated leiomyosarcoma, immunohistochemical staining supported that diagnosis. Leiomyosarcomas are rare among North American cattle. In this case, the primary neoplasm appears to have originated in the wall of the vena cava within the liver. Key clinical message: This report adds to the limited information on leiomyosarcomas in cattle, while highlighting both the challenges faced by veterinarians conducting post-mortem examinations on large animals in below freezing temperatures, as well as the current methods available to arrive at a diagnosis of a rare disease.

Léiomyosarcome métastatique présumé chez un bouvillon de parc d'engraissement. Un bouvillon de parc d'engraissement âgé de 14 mois était abattu et est mort pendant son examen. L'examen macroscopique du bouvillon réalisée au parc d'engraissement a identifié de nombreuses masses dans l'abdomen et le thorax, y compris une grosse masse dans le foie qui s'est étendue dans la veine cave. De nombreuses masses dans les poumons semblaient être le résultat d'une distribution hématogène. L'examen histologique des masses a confirmé la présence d'un néoplasme. Bien que l'aspect histologique du néoplasme ne soit pas typique d'un léiomyosarcome bien différencié, la coloration immunohistochimique a corroboré ce diagnostic. Les léiomyosarcomes sont rares chez les bovins nord-américains. Dans ce cas, le néoplasme primaire semble provenir de la paroi de la veine cave dans le foie.Message clinique clé :Ce rapport s'ajoute aux informations limitées sur les léiomyosarcomes chez les bovins, tout en soulignant à la fois les défis auxquels sont confrontés les vétérinaires effectuant des examens post-mortem sur de grands animaux à des températures inférieures au point de congélation, ainsi que les méthodes actuelles disponibles pour arriver à un diagnostic d'une maladie rare.(Traduit par Dr Serge Messier).

Evaluation of metallothionein and Ki-67 expression in chronic cholangiohepatitis in cats.

Chronic cholangiohepatitis (CCH) is a common pathological condition in cats with a guarded prognosis and unknown etiology. Recently, in human medicine, there has been increased interest in enhancing liver defense mechanisms as an effective treatment strategy to control liver diseases that have a poor prognosis. Metallothionein (MT) is a ubiquitous protein, which has been widely researched for its role in liver defense through heavy metal detoxification, neutralization of reactive oxygen species, and liver regeneration. In this study, immunohistochemistry was used to evaluate the role of MT in CCH and hepatocellular regeneration in 34 cats histologically diagnosed with this condition by assessing the correlation between hepatocellular MT and Ki-67 (marker for cellular proliferation) expression with histological parameters of CCH, such as inflammation, fibrosis, and bile duct proliferation. Statistical analysis was performed using the Spearman-rank correlation test. A significant positive correlation was observed between inflammation and the number of MT-positive hepatocytes (r = 0.36, P = 0.03) and MT labelling intensity (r = 0.37, P = 0.03). In 16 of 34 cases (47%) MT labelling intensity was noted to be pronounced towards the centrilobular zone and very weak or absent towards the portal zone. The results suggest that MT is induced in the liver during chronic inflammatory conditions, which could be speculated as a host defensive mechanism to protect the liver from inflammation-mediated liver injury. Therapeutic interventions utilizing MT, therefore, may have a positive effect on cats with chronic cholangiohepatitis.

La cholangiohépatite chronique (CCH) est une affection pathologique courante chez les chats avec un pronostic réservé et une étiologie inconnue. Récemment, en médecine humaine, il y a eu un intérêt accru pour l'amélioration des mécanismes de défense hépatique en tant que stratégie de traitement efficace pour contrôler les maladies du foie qui ont un mauvais pronostic. La métallothionéine (MT) est une protéine omniprésente, qui a été largement étudiée pour son rôle dans la défense du foie par la détoxification des métaux lourds, la neutralisation des espèces réactives de l'oxygène et la régénération du foie. Dans cette étude, l'immunohistochimie a été utilisée pour évaluer le rôle de la MT dans la CCH et la régénération hépatocellulaire chez 34 chats diagnostiqués histologiquement avec cette condition en évaluant la corrélation entre l'expression hépatocellulaire de la MT et du Ki-67 (marqueur de la prolifération cellulaire) avec les paramètres histologiques de la CCH, comme l'inflammation, la fibrose et la prolifération des voies biliaires. L'analyse statistique a été réalisée à l'aide du test de corrélation de rang de Spearman. Une corrélation positive significative a été observée entre l'inflammation et le nombre d'hépatocytes MT-positifs (r = 0,36, P = 0,03) et l'intensité de marquage MT (r = 0,37, P = 0,03). Dans 16 des 34 cas (47 %), l'intensité du marquage MT était prononcée vers la zone centrolobulaire et très faible ou absente vers la zone porte. Les résultats suggèrent que la MT est induite dans le foie pendant les états inflammatoires chroniques, ce qui pourrait être supposé comme un mécanisme de défense de l'hôte pour protéger le foie contre les lésions hépatiques induites par l'inflammation. Les interventions thérapeutiques utilisant la MT peuvent donc avoir un effet positif sur les chats atteints de cholangiohépatite chronique.(Traduit par Docteur Serge Messier).

Canine eosinophilic pulmonary granulomatosis: case report and literature review.

We describe and illustrate herein a case of eosinophilic pulmonary granulomatosis (EPG) in a 16-mo-old, castrated male, Great Pyrenees crossbred dog. EPG appears to differ from eosinophilic pneumonias and eosinophilic bronchopneumopathy in dogs by the presence of nodules and masses in the lungs composed of eosinophils, macrophages, and various combinations of lymphocytes, plasma cells, neutrophils, and mast cells within fibrous tissue. Specific information from this dog was added to the information from the limited number of other dogs diagnosed with EPG reported in the veterinary literature, and the information analyzed. EPG appears to have no breed or sex predilection and tends to be a disease of younger dogs, often ≤ 3 y of age. Antemortem imaging of nodules and masses in the lungs, combined with cytologic evidence of eosinophils in the lesions, is highly suggestive of EPG, and the diagnosis can be confirmed postmortem. Concurrent eosinophilia and basophilia can be features of EPG, but their diagnostic value requires further investigation, as does the possible causal association with Dirofilaria immitis infection.

Histologic assessment of age-related changes in the temporomandibular joints of horses.

OBJECTIVE: To describe histologic changes in the temporomandibular joints (TMJs) of horses of various ages. SAMPLE: 22 TMJs from cadavers of 11 horses. PROCEDURES: Horses were categorized into 3 age groups (group 1, 2 to 10 years old [n = 3]; group 2, 11 to 20 years old [3]; and group 3, > 20 years old [5]). Each TMJ was sectioned into 5-mm slices, preserved in formalin, decalcified in formic acid, and routinely processed for histologic analysis. Joints were systematically assessed by use of previously described methods. Multilevel mixed-effects models were used to examine the data. RESULTS: The number of changes was significantly fewer and degree of changes was significantly less within the TMJs of group 1 horses, compared with those of group 3 horses. Comparison among groups revealed that the combination of temporal and mandibular scores for group 1 was significantly lower than for groups 2 or 3. Disk score did not differ significantly between groups 1 and 2, but disk scores of groups 1 and 2 were significantly lower than the disk score of group 3. CONCLUSIONS AND CLINICAL RELEVANCE: The assessed lesions were associated with osteoarthritis, and they accumulated in the TMJs as horses aged. In the absence of signs of pain manifested as changes in mastication, behavior, or performance, it would be difficult to determine the point at which accrued pathological changes represented the onset of clinically important osteoarthritis of the TMJs.

Novel technique for prevention of rotation of the distal phalanx relative to the hoof wall in horses with acute laminitis.

OBJECTIVE: To determine the holding capacity of a 5.5-mm-diameter cortical bone screw when placed in the third phalanx (P3) of horses and assess whether screw placement through the dorsal hoof wall into P3 would be tolerated by clinically normal horses and would alleviate signs of pain and prevent P3 rotation in horses with oligofructose-induced laminitis. ANIMALS: 40 limbs from 10 equine cadavers and 19 clinically normal adult horses. PROCEDURES: In part 1 of a 3-part study, a 5.5-mm-diameter cortical bone screw was inserted by use of a lag-screw technique through the dorsal hoof wall midline into P3 of 40 cadaveric limbs and tested to failure to determine screw pullout force. In part 2, 6 horses had 5.5-mm-diameter cortical bone screws placed in both forefeet as described for part 1. Screws were removed 4 days after placement. Horses were monitored for lameness before and for 2 weeks after screw removal. In part 3, 13 horses were randomly assigned to serve as controls (n = 3) or undergo screw placement without (group 2; 6) or with (group 3; 4) a washer. Following the acquisition of baseline data, horses were sedated and administered oligofructose (10 g/kg) via a stomach tube. Twenty-four hours later, screws were placed as previously described in both forefeet of horses in groups 2 and 3. Horses were assessed every 4 hours, and radiographic images of the feet were obtained at 96 and 120 hours after oligofructose administration. Horses were euthanized, and the feet were harvested for histologic examination. RESULTS: The mean ± SD screw pullout force was 3,908.7 ± 1,473.4 N, and it was positively affected by the depth of screw insertion into P3. Horses of part 2 tolerated screw placement and removal well and did not become lame. All horses of part 3 developed signs of acute lameness, and the distance between P3 and the dorsal hoof wall increased slightly over time. The change in the ratio of the dorsal hoof wall width at the extensor process of P3 to that at the tip of P3 over time was the only variable significantly associated with treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Placement of a 5.5-mm-diameter cortical bone screw through the dorsal hoof wall into P3 had sufficient holding power to counteract the pull of the deep digital flexor tendon in approximately 500-kg horses, and placement of such a screw was well tolerated by clinically normal horses but did not alleviate signs of pain in horses with oligofructose-induced laminitis. Further research is necessary before this technique can be recommended for horses with naturally occurring acute laminitis.

Metallothionein Expression in Horses With Chronic Liver Disease and Its Correlation With Ki-67 Immunoreactivity.

Chronic liver disease is an important cause of illness in horses, and treatment is mainly supportive. Research into new treatment modalities for humans has shown promising data regarding metallothionein (MT), which has been shown to possess regenerative, antifibrotic, and anti-inflammatory properties. This study aimed to examine the relationship between hepatic MT expression and the histopathologic markers of hepatic inflammation, fibrosis and bile duct proliferation, as well as cellular regeneration in 77 selected cases of chronic liver disease in horses. We hypothesized that higher MT expression would be associated with increased heptocellular proliferation and decreased fibrosis, inflammation, and bile duct proliferation. Hepatocellular MT expression was evaluated with immunohistochemistry. Additionally, cellular regeneration was evaluated with immunohistochemistry for Ki-67, a protein expressed during all active stages of the cell cycle. The severity of inflammation and fibrosis was scored, and bile duct proliferation was assessed by counting bile duct profiles. MT expression was observed in 73 of 77 (94.8%) cases of chronically diseased livers. Ki-67 expression was seen in resident Kupffer cells ( n = 42, 54.6%), lymphocytes ( n = 39, 50.7%), bile duct epithelium ( n = 10, 13.0%), and hepatocytes ( n = 8, 10.4%). MT expression was significantly associated with Ki-67 staining in bile duct epithelium and Kupffer cells. Additionally, median MT expression was higher in cases containing lymphocytic infiltrates as compared with cases with no lymphocytic infiltrate ( P < .05). These findings are the first known report of MT expression within chronic equine hepatic disease.

Profiles of pro-opiomelanocortin and encoded peptides, and their processing enzymes in equine pituitary pars intermedia dysfunction.

Equine pituitary pars intermedia dysfunction (PPID) is characterized by hyperplasia of the pars intermedia (PI) melanotrophs of the pituitary gland (PG), and increased production of proopiomelanocortin (POMC). POMC is cleaved by prohormone convertase 1 (PC1) to produce adrenocorticotropic hormone (ACTH), and further processing of ACTH by PC2 to produce alpha-melanocyte stimulating hormone (α-MSH) and corticotropin-like intermediate peptide (CLIP). High plasma ACTH concentrations in horses with PPID might be related to reduced conversion of ACTH to α-MSH by PCs. The hypothesis of this study was that PC1 and PC2 expression in the pituitary gland are altered in PPID, resulting in an abnormal relative abundance of POMC derived proteins. The objectives of this study were to identify the partial sequences of equine POMC, PC1, and PC2 mRNAs; and to determine whether the expression of POMC, PC1, and PC2 mRNAs in whole pituitary extracts, and POMC-protein in the cavernous sinus blood of horses are altered in PPID. We confirmed (RT-PCR and sequencing) that the partial sequences obtained match the corresponding regions of predicted equine POMC, PC1 and PC2 sequences. The expression (quantification by RT-qPCR) of POMC, PC1 and PC2 mRNAs were found upregulated in the pituitary of horses with PPID. Plasma (measured using RIA/ELISA) ACTH and α-MSH were elevated in PPID horses. These results indicate distinct differences in gene and protein expression of POMC and its intermediates, and processing enzymes in PPID. It provides evidence to support the notion that local, pituitary-specific inadequacies in prohormone processing likely contribute to equine PPID.

Equine pituitary pars intermedia dysfunction: An international survey of veterinarians' approach to diagnosis, management, and estimated prevalence.

The objectives of the present study were to determine if diagnosis and treatment of equine pituitary pars intermedia dysfunction (PPID) vary by geographic region and to report the prevalence of PPID in horses as observed by veterinarians across locations. An online questionnaire was developed for veterinarians who treat horses. Veterinary associations, especially equine specialty subgroups, were contacted and a survey link was sent to members of each organization. Generalized linear models were used to examine whether the method of diagnosis and treatment of this condition, as well as its reported prevalence, differed by geographic region. Veterinarians from 426 separate clinics in 20 countries returned surveys. Diagnosis of PPID varied by region, but was usually based on clinical signs and an adjunct endocrine test. Horses with PPID were treated medically by 63% of veterinarians and 75% of these used pergolide mesylate as treatment. The median prevalence estimated was 1% and this did not differ by geographic location. Half the veterinarians were caring for 5 or more animals with PPID. Overall, diagnostic approach differed in geographic regions. In general, European veterinarians were more likely than those in North America to diagnose PPID based on clinical signs alone, without using an adjunct laboratory test. Veterinarians reported that cost and management responsibilities were their clients' primary concerns associated with the long-term treatment of this disease, which indicates a need for additional treatment options for PPID.

Les objectifs de la présente étude étaient de déterminer si le diagnostic et le traitement de la dysfonction de l'hypophyse médiale équine (DHME) varient selon la région géographique et signalent la prévalence de la DHME chez les chevaux, comme l'ont observé les vétérinaires dans différentes localisations. Un questionnaire en ligne a été développé pour les vétérinaires qui traitent les chevaux. Les associations vétérinaires, en particulier les sous-groupes de spécialités équines, ont été contactées et un lien pour un sondage a été envoyé aux membres de chaque organisation. Les modèles linéaires généralisés ont été utilisés pour examiner si la méthode de diagnostic et de traitement de cette condition, ainsi que sa prévalence déclarée, différaient selon la région géographique. Les vétérinaires provenant de 426 cliniques distinctes dans 20 pays ont répondu au sondage. Le diagnostic de DHME variait selon la région, mais était généralement basé sur les signes cliniques et un test endocrinien complémentaire. Les chevaux atteints de DHME ont été traités médicalement par 63 % des vétérinaires et 75 % de ceux-ci utilisaient le mésylate de pergolide comme traitement. La prévalence médiane estimée était de 1 % et cela ne différait pas selon la situation géographique. La moitié des vétérinaires prenaient soin de 5 animaux ou plus avec DHME. Dans l'ensemble, l'approche diagnostique différait selon les régions géographiques. En général, les vétérinaires européens étaient plus susceptibles que ceux en Amérique du Nord de diagnostiquer la DHME en se basant uniquement sur les signes cliniques, sans utiliser un test de laboratoire complémentaire. Les vétérinaires ont signalé que les coûts et les responsabilités en matière de gestion étaient les principales préoccupations de leurs clients liées au traitement à long terme de cette maladie, ce qui indique un besoin d'options de traitement supplémentaires pour DHME.(Traduit par Docteur Serge Messier).

Neoplasia in 125 donkeys (Equus asinus): literature review and a survey of five veterinary schools in the United States and Canada.

A diagnosis of neoplasia was noted in 125 of 357 donkeys (35%) in our review of medical records from 5 veterinary schools in the United States and Canada. Equine sarcoid was the most common tumor in our study, accounting for 72% of all tumors and 82% of cutaneous tumors. Soft-tissue sarcomas were the second most common skin tumors. All other types of neoplasia were rare. Important differences in the occurrence of neoplasia in donkeys compared to horses included the rarity or absence of squamous cell carcinoma in any organ system and gray horse melanoma. Lymphosarcoma, the most common malignant tumor in horses, appears to be very rare in donkeys. We report several tumors in donkeys including melanocytoma, peripheral nerve sheath tumor, and gastrointestinal stromal tumor. Our data demonstrate commonalities as well as differences in neoplastic diseases of donkeys and horses. Understanding differences in carcinogenesis among these 2 closely related species can inform researchers pursuing pathogenic mechanisms of equine disease and inform veterinary diagnosticians regarding tumor prevalence.

The lesions of toe tip necrosis in southern Alberta feedlot cattle provide insight into the pathogenesis of the disease.

Gross and histologic postmortem studies were performed on the hind feet of feedlot cattle that had, or were free from, lesions of toe tip necrosis. The hind feet of feedlot cattle were collected by 3 veterinary feedlot practices in southern Alberta, Canada. Three studies of these feet were conducted: i) prediction of disease based on the presence or absence of apical white line separation, ii) gross assessment of the distribution and severity of lesions within affected claws, and iii) microscopic evaluation of the distal phalanx and surrounding soft tissues of affected claws. Prediction of toe tip necrosis based on the presence of apical white line separation was statistically significant (P < 0.0001). This, combined with a pattern of lesions indicative of an ascending infection of the distal phalanx and the absence of other lesions, suggests that the pathogenesis involves bacterial infection originating from the most distal aspect of the toe, at the apical white line.

Les lésions de la nécrose du bout des orteils chez le bétail des parcs d'engraissement du sud de l'Alberta fournissent des renseignements sur la pathogénèse de la maladie. Des études post-mortem macroscopiques et histologiques ont été réalisées sur les pieds arrière du bétail d'engraissement qui avait ou n'avait pas des lésions de nécrose du bout des orteils. Les pieds arrière du bétail d'engraissement ont été recueillis par trois pratiques vétérinaires de parcs d'engraissement du sud de l'Alberta, au Canada. Trois études de ces pieds ont été réalisées : i) prédiction de la maladie en fonction de la présence ou de l'absence d'une séparation de la ligne blanche apicale, ii) une évaluation macroscopique de la répartition et de la gravité des lésions dans les onglons affectés et iii) une évaluation microscopique des phalanges distales et des tissus mous entourant les onglons affectés. La prédiction de la nécrose du bout des orteils basée sur la présence d'une séparation de la ligne blanche apicale était significative du point de vue statistique (P < 0,0001). Ce fait, combiné à une tendance de lésions indiquant une infection ascendante des phalanges distales et l'absence d'autres lésions, suggère que la pathogénèse comporte une infection bactérienne provenant de l'aspect le plus distal de l'orteil, à la ligne blanche apicale.(Traduit par Isabelle Vallières).

Chronic active interstitial pancreatitis as a cause of transverse colonic obstruction and colic in a horse.

A mature Quarter horse was euthanized following colic of 3 days duration. Postmortem, the large intestine, except the descending colon, was diffusely distended and associated with adhesion of the transverse colon to the pancreas, which had changes consistent with chronic active interstitial pancreatitis. Other lesions included hepatic fibrosis, erosive gastritis, and bilateral adrenal cortical hyperplasia.

Pancréatite interstitielle chronique active comme cause d'une obstruction du côlon transversal et de coliques chez un cheval. Un cheval Quarter horse adulte a été euthanasié après des coliques d'une durée de 3 jours. À l'autopsie, il a été observé que le gros intestin, sauf le côlon descendant, présentait une distension diffuse et était associé à l'adhésion du côlon transversal au pancréas qui indiquait des changements conformes à une pancréatite interstitielle chronique active. Les autres lésions incluaient une fibrose hépatique, une gastrite érosive et une hyperplasie corticale bilatérale des surrénales.(Traduit par Isabelle Vallières).

Optic neuropathy in a herd of beef cattle in Alberta associated with consumption of moldy corn.

A group of beef cattle in eastern Alberta was investigated due to sudden onset of blindness after grazing on standing corn in mid-winter. Fumonisin-producing Fusarium spp. were isolated from the corn. Blindness was due to an optic nerve degeneration suspected to be secondary to fumonisin mycotoxin.

Neuropathie optique dans un cheptel de bovins de boucherie en Alberta associée à la consommation de maïs moisi. Un groupe de bovins de boucherie de l'est de l'Alberta a fait l'objet d'une enquête en raison de l'apparition soudaine de cécité après avoir brouté du maïs sur pied vers le milieu de l'hiver. Fusarium spp., qui produit la fumonisine, a été isolé dans le maïs. La cécité a été attribuable à la dégénération du nerf optique ayant pour cause suspectée la mycotoxine fumonisine.(Traduit par Isabelle Vallières).

Species-specificity of equine and porcine Lawsonia intracellularis isolates in laboratory animals.

Lawsonia intracellularis infection causes proliferative enteropathy (PE) in many mammalian species, with porcine and equine proliferative enteropathy (PPE and EPE) known worldwide. Hamsters are a well-published animal model for PPE infection studies in pigs. There is no laboratory animal model for EPE infection studies and it is not known whether there is species-specificity for equine or porcine isolates of L. intracellularis in animal models. The objective of this study was to determine whether it is possible to generate typical EPE lesions in hamsters after inoculation with an equine strain of L. intracellularis (EPE strain) and whether it is comparatively possible to generate PPE lesions in rabbits after inoculation with a porcine strain of L. intracellularis (PPE strain). In 2 separate trials, 4-week-old and 3-week-old weanling golden Syrian hamsters were challenged with EPE strains and compared to uninfected (both trials) and PPE-infected controls (Trial 2 only). Concurrently, 6 female New Zealand white juvenile rabbits were infected with PPE strain and observed concomitantly to 8 similar rabbits infected with EPE strain for a different experiment. Hamsters and rabbits were observed for 21 to 24 days post-infection (DPI), depending on the experiment. Neither infected species developed clinical signs. The presence of disease was assessed with diagnostic techniques classically used for pigs and horses: immune-peroxidase monolayer assay on sera; quantitative polymerase chain reaction (qPCR) detection of molecular DNA in feces; and hematoxylin and eosin (H&E) stain and immunohistochemistry (IHC) on intestinal tissues. Our results showed that EPE-challenged hamsters do not develop infection when compared with PPE controls (IHC, P = 0.009; qPCR, P = 0.0003). Conversely, PPE-challenged rabbits do not develop typical intestinal lesions in comparison to EPE-challenged rabbits, with serological response at 14 DPI being significantly lower (P = 0.0023). In conclusion, PPE and EPE strains appear to have different host-specificities for hamsters and rabbits, respectively.

L'infection par Lawsonia intracellularis provoque une entéropathie proliférative chez de nombreuses espèces de mammifères; celle des porcins (EPP) et des équidés (EEP) sont connues mondialement. Les hamsters sont un modèle animal bien connu pour l'étude de l'EPP. Il n'existe pas de modèle animal de laboratoire pour étudier l'EEP, et on ne sait pas s'il y a spécificité d'espèce pour les isolats équins ou porcins de L. intracellularis dans des modèles animaux. L'objectif de la présente étude était de déterminer s'il est possible de générer des lésions typiques d'EEP chez les hamsters après inoculation d'une souche équine de L. intracellularis (souche EEP) et s'il est également possible de générer des lésions d'EPP chez des lapins après inoculation d'une souche porcine de L. intracellularis (souche EPP). Dans 2 essais séparés, des hamsters dorés syriens sevrés âgés de 4 semaines et de 3 semaines ont été inoculés avec des souches EEP, et ont été comparés à des témoins non infectés (les deux essais) et à des témoins infectés avec EPP (essai 2 seulement). Parallèlement, 6 jeunes lapines Nouvelle-Zélande ont été infectées par la souche EEP et observées de façon concomitante à 8 lapins similaires infectés par la souche EPP pour une expérience différente. Les hamsters et les lapins ont été observés pendant 21 à 24 jours après l'infection (JAI), en fonction de l'expérience. Aucune des espèces infectées n'a développé de signes cliniques. La présence de maladie a été évaluée par des techniques classiques de diagnostic utilisées pour les porcs et les chevaux : l'essai par immuno-peroxydase sur monocouche pour les sérums; la détection par réaction d'amplification en chaîne par la polymérase quantitative (qPCR) de l'ADN moléculaire dans les selles; la coloration hématoxyline-éosine et l'immunohistochimie (IHC) sur des tissus intestinaux. Nos résultats ont montré que les hamsters inoculés avec EEP ne développent pas d'infection comparativement aux EPP témoins (IHC P = 0,009; qPCR P = 0,0003). À l'inverse, les lapins inoculés avec EPP ne développent pas des lésions intestinales typiques comparativement aux lapins inoculés avec EEP, avec une réponse sérologique à 14 JAI significativement plus faible (P = 0,0023). En conclusion, les souches d'EPP et d'EEP semblent avoir des spécificités d'hôte différentes chez les hamsters et les lapins, respectivement.(Traduit par Dr. J.M. Dhillon).

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).

The rabbit as an infection model for equine proliferative enteropathy.

The objective of this study was to demonstrate the susceptibility of rabbits to Lawsonia intracellularis obtained from a case of clinical equine proliferative enteropathy (EPE). This is a preliminary step toward developing a rabbit infection model for studying pathogenesis and therapy of EPE in horses. Nine does were equally assigned to 3 groups. Animals in 2 groups (Group 1 and Group 2) were orally inoculated with different doses of cell-cultured L. intracellularis. Controls (Group 3) were sham-inoculated. Feces and blood were collected before the rabbits were infected and at 7, 14, and 21 days post-infection (DPI). Serum immunoglobulin G (IgG) titers were measured using an immunoperoxidase monolayer assay (IPMA) and fecal samples were analyzed with quantitative polymerase chain reaction (qPCR). A doe from each group was euthanized at 7, 14, and 21 DPI for collection and evaluation of intestinal samples. Tissues were stained by routine hematoxylin and eosin (H&E) method and immunohistochemistry (IHC) with L. intracellularis-specific mouse monoclonal antibody. At 14 DPI, serologic responses were detected in both infected groups, which maintained high titers through to 21 DPI. Lawsonia intracellularis DNA was detected in the feces of Group 2 on 7 DPI and in both infected groups on 14 DPI. Gross lesions were apparent in Group 1 and Group 2 on 14 DPI. Immunohistochemistry confirmed L. intracellularis antigen within cells of rabbits in Group 1 and Group 2 on 7, 14, and 21 DPI. No lesions, serologic response, shedding, or IHC labeling were found in Group 3 rabbits. This study describes an EPE rabbit model that simulates natural infection, as typical lesions, immune response, and fecal shedding were present.

Cette étude visait à démontrer la susceptibilité des lapins à Lawsonia intracellularis obtenu d'un cas clinique d'entéropathie proliférative équine (EPE). Ceci est une étape préliminaire dans le développement d'un modèle d'infection chez le lapin pour étudier la pathogénie et le traitement de l'EPE chez les chevaux. Neuf lapines ont été assignées également à 3 groupes. Les animaux dans deux groupes (Groupe 1 et Groupe 2) ont été inoculés oralement avec différentes doses de L. intracellularis cultivés sur cellules. Les témoins (Groupe 3) étaient faussement inoculés. Des fèces et du sang ont été prélevés avant que les lapins soient infectés et aux jours 7, 14 et 21 post-infection (DPI). Les titres sériques d'immunoglobulines G (IgG) ont été mesurés par une épreuve d'immunoperoxydase en monocouche (IPMA) et les échantillons de fèces ont été analysés par réaction quantitative d'amplification en chaîne par la polymérase (qPCR). Une lapine de chaque groupe a été euthanasiée 7, 14 et 21 DPI pour prélèvement et évaluation d'échantillons intestinaux. Les tissus étaient colorés à l'aide d'hématoxyline et éosine (H&E) et en immunohistochime (IHC) avec un anticorps monoclonal de souris spécifique à L. intracellularis. Au jour 14 post-infection, une réponse sérologique a été détectée chez les animaux des deux groupes infectés, et des titres élevés ont été maintenus jusqu'à 21 DPI. De l'ADN de L. intracellularis fut détecté dans les fèces du Groupe 2 au jour 7 PI et dans les 2 groupes infectés au jour 14 PI. Des lésions macroscopiques étaient apparentes dans le Groupe 1 et le Groupe 2 au jour 14 PI. L'immunohistochime a confirmé la présence d'antigène de L. intracellularis à l'intérieur des cellules de lapins dans les Groupes 1 et 2 aux jours 7, 14 et 21 PI. Aucune lésion, réponse sérologique, excrétion, ou marquage en IHC n'ont été trouvés chez les lapins du Groupe 3. La présente étude décrit un modèle lapin d'EPE qui imite l'infection naturelle, étant donné la présence de lésions typiques, de réponse immunitaire et d'excrétion fécale.(Traduit par Docteur Serge Messier).

A retrospective study of brain lesions in goats submitted to three veterinary diagnostic laboratories.

A retrospective study of brain lesions in goats was conducted to identify the range of lesions and diseases recognized and to make recommendations regarding the best tissues to examine and tests to conduct in order to maximize the likelihood of making a definitive diagnosis in goats that may have had clinical signs referable to the brain. One hundred thirty-nine goats with a brain lesion were identified. The most common lesion, in 52.5% of the goats, was suppurative inflammation. Approximately two-thirds of these goats had encephalitic listeriosis. Other goats were found to have suppurative inflammation in association with septicemia, pituitary abscesses, dehorning injury, and otitis. Thirty goats (21.6%) were diagnosed with polioencephalomalacia. Twenty-one goats (15.1%) were diagnosed with nonsuppurative inflammation. In more than half of these goats, no definitive diagnosis was made, while 8 were infected with Caprine arthritis encephalitis virus and 1 with Rabies virus. However, few goats were tested for rabies. Based on these findings, it is recommended that, in addition to appropriate handling of the brain, the head should be examined with attention paid to the sella turcica and the temporal bones for evidence of a pituitary abscess and otitis, respectively. Histologic examination should include multiple areas of the brain, including the brainstem, for lesions of encephalic listeriosis; the cerebral cortex, for lesions of polioencephalomalacia; and the hippocampus, for Negri bodies associated with Rabies virus infection. Consideration should be given to collecting samples of other tissues including, but not limited to, the spinal cord and liver for ancillary testing if warranted.

A retrospective study of spinal cord lesions in goats submitted to 3 veterinary diagnostic laboratories.

A retrospective study of spinal cord lesions in goats was conducted to identify the range of lesions and diseases recognized and to make recommendations regarding the best tissues to examine and tests to conduct in order to maximize the likelihood of arriving at a definitive etiologic diagnosis in goats with clinical signs referable to the spinal cord. Twenty-seven goats with a spinal cord lesion were identified. The most common lesion recognized, in 13 of 27 goats, was degenerative myelopathy. Eight goats with degenerative myelopathy were diagnosed with copper deficiency. Non-suppurative inflammation due to caprine arthritis encephalitis virus, necrosis due to parasite larvae migration, and neoplasia were each diagnosed 3 times. Based on these findings, it is recommended that, in addition to careful handling and histologic examination of the spinal cord, samples of other tissues, including the brain, liver, and serum, be collected for ancillary testing if warranted.

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.