Fecal Shedding of Clostridioides difficile in Calves in Sao Paulo State, Brazil.

OBJECTIVE: This study aimed to evaluate the fecal shedding of C. difficile in calves on farms in Sao Paulo State, Brazil. MATERIALS AND METHODS: Fecal samples (n=300) were collected from diarrheic (n=78) and nondiarrheic (n=222) calves less than 60 days of age from 20 farms. Fecal samples were inoculated into enrichment broth supplemented with taurocholate and cultured under anaerobic conditions. Colonies suspected to be C. difficile were harvested for DNA extraction and then multiplex PCR for the detection of genes encoding toxins A and B and binary toxins. All toxigenic isolates were ribotyped and tested for antimicrobial susceptibility, and five selected strains were subjected to whole-genome sequencing to determine their sequence type. RESULTS AND DISCUSSION: C. difficile was isolated from 29.3% (88/300) of the samples. All toxigenic isolates (17/88, 19.3%) were classified as ribotypes RT046 (13/17 -79.47%, A+B+ CDT-) and RT126 (4/17=20.53%, A+B+ CDT+). The sequenced strains from RT046 were classified as ST35 (Clade 1), while those from RT126 were classified as ST11 (Clade 5). No associations between the epidemiological factors in any of the groups and C. difficile isolation were observed. Most of the toxigenic isolates (16/17=94.41%) were classified as multidrug-resistant. Calves can be an important source of toxigenic C. difficile strains, including multidrug-resistant isolates from ribotypes commonly observed in humans.

Diagnosis of Potomac horse fever (syn. equine neorickettsiosis) in 2 foals in southwestern Ontario.

Potomac horse fever (PHF) is characterized by fever, depression, anorexia, ileus, diarrhea, and occasionally, laminitis. The disease is caused by infection with Neorickettsia risticii and/or N. findlayensis. Equids of all ages may be affected; however, the condition has not been well-characterized in foals. This report describes clinical signs, laboratory findings, and treatment of 2 foals diagnosed with PHF in southwestern Ontario. Feces submitted for an equine PCR panel tested positive for Neorickettsia spp. and were subsequently confirmed to be N. risticii (Case 1) and N. findlayensis (Case 2). Both foals recovered following hospitalization and intensive care. Key clinical message: The purpose of this report is to make veterinarians aware that foals may develop PHF. During summer (July to September), when encountering foals in endemic areas with clinical signs compatible with PHF, veterinarians should consider PHF as a diagnostic rule-out. For confirmation of the diagnosis, blood and feces should be submitted for PCR testing for Neorickettsia spp.

Diagnostic de la fièvre équine du Potomac (syn. néorickettsiose équine) chez 2 poulains dans le sud-ouest de l'Ontario. La fièvre équine du Potomac (PHF) se caractérise par de la fièvre, une dépression, de l'anorexie, un iléus, de la diarrhée et, occasionnellement, une fourbure. La maladie est causée par une infection par Neorickettsia risticii et/ou N. findlayensis. Les équidés de tous âges peuvent être atteints; cependant, cette pathologie n'a pas été bien caractérisée chez les poulains. Ce rapport décrit les signes cliniques, les résultats de laboratoire et le traitement de 2 poulains diagnostiqués avec PHF dans le sud-ouest de l'Ontario. Les matières fécales soumises à un panel PCR équin se sont révélées positives pour Neorickettsia spp. et ont ensuite été confirmées comme étant positives pour N. risticii (cas 1) et N. findlayensis (cas 2). Les deux poulains se sont rétablis après une hospitalisation et des soins intensifs.Message clinique clé :Le but de ce rapport est de sensibiliser les vétérinaires au fait que les poulains peuvent développer une PHF. Pendant l'été (juillet à septembre), lorsqu'ils rencontrent des poulains dans des zones d'endémie présentant des signes cliniques compatibles avec le PHF, les vétérinaires doivent considérer le PHF comme une exclusion diagnostique. Pour confirmer le diagnostic, du sang et des selles doivent être soumis à un test PCR pour Neorickettsia spp.(Traduit par Dr Serge Messier).

Survival rates and factors associated with survival and laminitis of horses with acute diarrhoea admitted to referral institutions.

BACKGROUND: Clinicopathological findings and their association with the outcome and development of laminitis in horses with acute diarrhoea has not been investigated in a multicentre study across different geographic regions. OBJECTIVES: Describe and compare clinicopathologic findings of diarrhoeic horses between different geographic regions, survival rates and factors associated with non-survival and laminitis. STUDY DESIGN: Multicentre retrospective case series. METHODS: Information from horses with acute diarrhoea presenting to participating institutions between 2016 and 2020 was collected, and clinicopathological data were compared between surviving and non-surviving horses and horses that did and did not develop laminitis. Survival rates and seasonal and geographic differences were also investigated. RESULTS: One thousand four hundred thirty-eight horses from 26 participating institutions from 4 continents were included; 76% survived to discharge with no differences identified between geographic regions. The survival proportion of horses with SIRS and creatinine concentrations > 159 µmol/L was 55% (154/279) compared with 81% (358/437) for those with SIRS and creatinine concentrations < 159 µmol/L (p < 0.001). The survival proportion of horses with SIRS that had an L-lactate concentration > 2.8 mmol/L was 59% (175/298) compared with 81% (240/296) in horses with SIRS and L-lactate concentration < 2.8 mmol/L (p < 0.001). The proportion of horses that developed laminitis was lower in Europe (4%, 19/479) compared with North America (8%, 52/619), Australia (8%, 12/138) and Latin America (11%, 16/146) (p < 0.05). More horses developed laminitis in the summer (46%, 39/85) compared with winter (18%, 15/85), spring (18%, 15/85) and fall (19%, 16/85) (p < 0.01). Horses with laminitis had greater odds of non-survival than those without laminitis (OR: 3.73, 95% CI: 2.47-5.65). MAIN LIMITATIONS: Not all variables were available for all horses due to the retrospective nature. CONCLUSIONS: Clinicopathological findings in horses with acute diarrhoea and their association with survival are similar across geographic regions. However, developing laminitis secondary to diarrhoea is less common in Europe. In addition, factors associated with non-survival were indicative of disease severity and subsequent cardiovascular compromise.

CONTEXTO: Achados clínico-patológicos e suas associações com o sobrevivência e desenvolvimento de laminite em cavalos com diarreia aguda não foram investigados em um estudo multicêntrico envolvendo diferentes regiões geográficas. OBJETIVOS: Descrever e comparar achados clínico-patológicos de cavalos com diarreia em diferentes regiões geográficas, taxa de sobrevivência e fatores associados com mortalidade e laminite. DELINEAMENTO DO ESTUDO: Estudo multicêntrico retrospectivo de série de casos. METODOLOGIA: Informação sobre equinos com diarreia aguda apresentados às instituições participantes entre 2016 e 2020 foram coletados, e dados clínico-patológicos foram comparados entre sobreviventes e não-sobreviventes, e cavalos que desenvolveram ou não laminite. Taxa de sobrevivência, e diferenças sazonais e geográficas também foram investigadas. RESULTADOS: 1438 cavalos de 26 instituições participantes de 4 continentes foram incluídos; 76% sobreviveram e receberam alta e nenhuma diferença foi observada entre as diferentes regiões geográficas. A proporção de cavalos que sobreviveram com SIRS e concentração de creatinina > 1.8 mg/dL foi 55% (154/279) comparado com 81% (358/437) dos cavalos com SIRS e concentração de creatinina < 1.8 mg/dL (p < 0.001). A proporção de cavalos com SIRS que tinham concentração de L-lactato > 2.8 mmol que sobreviveram foi 59% (175/298) comparado com 81% (240/296) dos cavalos com SIRS e concentração de L-lactato < 2.8 mmol/L (p < 0.001). A proporção de cavalos que desenvolveram laminite foi menor na Europa (4%, 19/479) comparado com a América do Norte (8%, 52/619), Austrália (8%, 12/138) e América Latina (11% 16/146) (p < 0.05). Mais cavalos desenvolveram laminite no verão (46%, 39/8) comparado com inverno (18%, 15/85), primavera (18%, 15/85) e outono (19%, 16/85) (p < 0.01). Cavalos com laminite tiveram chances maior de não sobreviver do que aqueles que não desenvolveram laminite (OR: 3.73, 95% CI: 2.47 a 5.65). PRINCIPAIS LIMITAÇÕES: Algumas variáveis não estavam disponíveis para alguns cavalos devido à natureza retrospectiva deste estudo. CONCLUSÕES: Achados clínico-patológicos em equinos com diarreia aguda e sua associação com sobrevivência é similar entre as diferentes regiões geográficas. Contudo, o desenvolvimento de laminite secundário à diarreia é menos comum na Europa. Além disso, fatores associados com não-sobrevivência foram indicativos de severidade da doença e subsequente comprometimento cardiovascular.

Diagnostic approaches, aetiological agents and their associations with short-term survival and laminitis in horses with acute diarrhoea admitted to referral institutions.

BACKGROUND: An international description of the diagnostic approaches used in different institutions to diagnose acute equine diarrhoea and the pathogens detected is lacking. OBJECTIVES: To describe the diagnostic approach, aetiological agents, outcome, and development of laminitis for diarrhoeic horses worldwide. STUDY DESIGN: Multicentre retrospective case series. METHODS: Information from horses with acute diarrhoea presenting to participating institutions between 2016 and 2020, including diagnostic approaches, pathogens detected and their associations with outcomes, were compared between institutions or geographic regions. RESULTS: One thousand four hundred and thirty-eight horses from 26 participating institutions from 4 continents were included. Overall, aetiological testing was limited (44% for Salmonella spp., 42% for Neorickettsia risticii [only North America], 40% for Clostridiodes difficile, and 29% for ECoV); however, 13% (81/633) of horses tested positive for Salmonella, 13% (35/262) for N. risticii, 9% (37/422) for ECoV, and 5% (27/578) for C. difficile. C. difficile positive cases had greater odds of non-survival than horses negative for C. difficile (OR: 2.69, 95%CI: 1.23-5.91). In addition, horses that were positive for N. risticii had greater odds of developing laminitis than negative horses (OR: 2.76, 95%CI: 1.12-6.81; p = 0.029). MAIN LIMITATIONS: Due to the study's retrospective nature, there are missing data. CONCLUSIONS: This study highlighted limited diagnostic investigations in cases of acute equine diarrhoea. Detection rates of pathogens are similar to previous reports. Non-survival and development of laminitis are related to certain detected pathogens.

Prevalence of equine parvovirus-hepatitis in healthy broodmares in Ontario, Canada.

Equine parvovirus-hepatitis (EqPV-H) was first reported from the serum and liver tissue of a horse diagnosed with Theiler's disease in the United States in 2018. Theiler's disease, also known as equine serum hepatitis, is a severe hepatitis with fulminant hepatic necrosis. The disease has most frequently been reported following the administration of equine-origin biological products; however, it has also been reported in in-contact horses with no prior biologic administration. EqPV-H has been detected in clinically healthy horses in North America (USA, Canada), Europe (Germany, Austria, Slovenia), Asia (China, South Korea), and South America (Brazil). Previous prevalence studies conducted worldwide have shown the presence of EqPV-H DNA in serum or plasma ranging from 3.2 to 19.8%. This study investigated the prevalence of EqPV-H DNA in 170 healthy broodmares of various breeds located on 37 farms in southern Ontario, Canada. The occurrence of EqPV-H infection was determined by quantitative PCR for EqPV-H DNA in serum samples. The effects of age, breed, season, pregnancy status, and equine herpesvirus-1 (EHV-1) vaccination history on EqPV-H status were also investigated. There was a prevalence of 15.9% (27/170) with viral loads of EqPV-H ranging from detectable to 2900 copies/mL. Statistical analysis showed that increasing age was a significant factor in the detection of EqPV-H DNA. Neither breed, season, pregnancy status, nor EHV-1 vaccination history was significant in predicting EqPV-H infection status.

L'hépatite à parvovirus équin (EqPV-H) a été signalée pour la première fois à partir du sérum et du tissu hépatique d'un cheval diagnostiqué avec la maladie de Theiler aux États-Unis en 2018. La maladie de Theiler, également connue sous le nom d'hépatite sérique équine, est une hépatite sévère avec nécrose hépatique fulminante. La maladie a été le plus souvent rapportée à la suite de l'administration de produits biologiques d'origine équine; cependant, il a également été signalé chez des chevaux en contact sans administration préalable de produit biologique. EqPV-H a été détecté chez des chevaux cliniquement sains en Amérique du Nord (États-Unis, Canada), en Europe (Allemagne, Autriche, Slovénie), en Asie (Chine, Corée du Sud) et en Amérique du Sud (Brésil). Des études de prévalence antérieures menées dans le monde entier ont montré la présence d'ADN EqPV-H dans le sérum ou le plasma allant de 3,2 à 19,8 %. Cette étude a examiné la prévalence de l'ADN EqPV-H chez 170 poulinières en bonne santé de différentes races situées dans 37 fermes du sud de l'Ontario, au Canada. La survenue d'une infection par EqPV-H a été déterminée par PCR quantitative pour l'ADN d'EqPV-H dans des échantillons de sérum. Les effets de l'âge, de la race, de la saison, de l'état de grossesse et des antécédents de vaccination contre l'herpèsvirus équin-1 (EHV-1) sur le statut EqPV-H ont également été étudiés. Il y avait une prévalence de 15,9 % (27/170) avec des charges virales d'EqPV-H allant de détectable à 2900 copies/mL. L'analyse statistique a montré que l'augmentation de l'âge était un facteur significatif dans la détection de l'ADN EqPV-H. Ni la race, ni la saison, ni l'état de grossesse, ni les antécédents de vaccination contre l'EHV-1 n'étaient significatifs pour prédire l'état de l'infection par l'EqPV-H.(Traduit par Docteur Serge Messier).

Postmortem examination of equids >1-year-old with enterotyphlocolitis in Ontario: a retrospective descriptive study.

Equine enterotyphlocolitis is an inflammatory process of the intestinal tract of horses that is associated with multiple etiologic agents and risk factors. Most clinical cases do not have an etiologic diagnosis. We describe here the pathogens detected and the histologic lesions found in horses with enterotyphlocolitis in Ontario that were submitted for postmortem examination, 2007-2019. We reviewed the medical records of 208 horses that fulfilled inclusion criteria. Cultures were positive in 67 of 208 (32%) equids for Clostridium perfringens, in 16 of 208 (8%) for Clostridioides difficile, and in 14 of 208 (7%) for Salmonella spp.; 6 of 208 (3%) were positive for Neorickettsia risticii by PCR assay. One horse was positive in a Rhodococcus equi PCR assay. All horses tested by PCR assay for equine coronavirus and Lawsonia intracellularis were negative. The histologic lesions were characterized as follows: 6 of 208 (3%) enteritis, 5 of 208 (2%) typhlitis, 104 of 208 (50%) colitis, 37 of 208 (18%) enterocolitis, 45 of 208 (22%) typhlocolitis, and 11 of 208 (5%) enterotyphlocolitis. We strongly recommend standardized testing of diarrheic horses during and/or after postmortem examination, as well as standardized reporting of histologic lesions in enterotyphlocolitis cases.

Direct and culture-enriched 16S rRNA sequencing of cecal content of healthy horses and horses with typhlocolitis.

Next generation sequencing has demonstrated that alpha diversity of the fecal microbiota is significantly altered in horses with typhlocolitis. The objective of this study was to evaluate the bacterial composition of the cecum content of horses with and without typhlocolitis through direct and culture-enriched 16S gene sequencing of six healthy horses and six horses with acute typhlocolitis; a case-control study design. Cecal content was collected after euthanasia. An aliquot was used for direct 16S gene sequencing. Another was serially diluted with brain heart infusion (BHI) and plated onto five different agar media. All culture medias, except for MacConkey, were incubated anaerobically. Bacterial colonies were harvested in bulk and used for DNA extraction, 16S PCR amplification, and sequenced using the Illumina MiSeq platform. Predominant phyla in healthy and diseased horses were Firmicutes, followed by Bacteroidetes in all cultured medias, except for MacConkey agar, in which Proteobacteria was the dominant phylum. Greater bacterial richness was identified in sequenced cecal contents as compared to cultured plates (P < 0.05). Culture-enriched molecular profiling combined with 16S rRNA gene sequencing offer an alternative method for the study of the gut microbiota of horses. For direct cecum content 16S gene amplification, the alpha diversity indices were lower in diarrheic horses compared to healthy horses (P < 0.05). A higher relative abundance of Fusobacteriota was found in 2/6 samples from diarrheic horses. The role of Fusobacteriota in equine colitis deserves investigation.

Effects of concentrated fecal microbiota transplant on the equine fecal microbiota after antibiotic-induced dysbiosis.

Bacterial imbalances are observed in intestinal diseases and fecal microbiota transplantation (FMT) has been used to restore the intestinal microbiota of horses. However, there is evidence that the current methods proposed for FMT in horses have limited efficacy. The objective of this study was to concentrate the bacteria present in the donor stool by centrifugation, and to test the effect in horses with antibiotic-induced dysbiosis. One healthy 11-year-old horse was selected as a fecal donor and 9 horses were given trimethoprim sulfadiazine (TMS) for 5 days to induce dysbiosis. Horses received either a concentrated FMT (cFMT, n = 3), fresh unconcentrated FMT (fFMT, n = 3), or 10% glycerol solution (vehicle, VEH, n = 3) by nasogastric tube for 3 days. Fecal samples were collected on Days 0, 4, 9, 11, and 21 for microbiota analysis (Illumina sequencing). The TMS significantly changed the bacterial composition of horses' feces (D0 versus D4). The composition of the cFMT and fFMT recipient horses was significantly different after transplantation compared to after antibiotic-induced dysbiosis (D4 versus D11), whereas the microbiota of the vehicle recipients was not, indicating that both protocols induced transient changes. However, preparation of FMT solutions markedly changed the original composition present in the donor's feces, with significant enrichment of Escherichia genus in the cFMT. Individual susceptibility to restoration of the microbiota was observed in horses, similar to what is known for other species. Our results suggest that concentrating bacteria should not be recommended in preparation of FMT solutions and that further research is required to improve current methods recommended to perform FMT in horses.

Des déséquilibres bactériens sont observés dans les maladies intestinales et la transplantation de microbiote fécal (FMT) a été utilisée pour la restaurer le microbiote intestinal des chevaux. Cependant, que les méthodes actuelles proposées pour FMT chez les chevaux ont une efficacité limitée. L'objectif de cette étude était de concentrer les bactéries présentes dans les selles du donneur par centrifugation, et de tester leur effet chez des chevaux atteints de dysbiose induite par les antibiotiques. Un cheval sain de 11 ans a été sélectionné comme donneur fécal et 9 chevaux ont reçu du triméthoprime sulfadiazine (TMS) pendant cinq jours pour induire une dysbiose. Les chevaux ont reçu soit une FMT concentrée (cFMT, n = 3), une FMT fraîche non concentrée (fFMT, n = 3) ou une solution de glycérol à 10 % (véhicule, VEH, n = 3) par sonde naso-gastrique pendant 3 jours. Des échantillons fécaux ont été prélevés aux jours 0, 4, 9, 11 et 21 pour analyse du microbiote (séquençage Illumina). Le TMS a significativement modifié la composition bactérienne des matières fécales des chevaux (D0 versus D4). La composition des chevaux receveurs cFMT et fFMT était significativement différente après la transplantation par rapport à la dysbiose induite par les antibiotiques (D4 versus D11), alors que le microbiote des receveurs de véhicules ne l'était pas, indiquant que les deux protocoles induisaient des changements transitoires. Cependant, la préparation des solutions FMT a considérablement modifié la composition originale présente dans les matières fécales du donneur, avec un enrichissement significatif du genre Escherichia dans le cFMT. Une susceptibilité individuelle à la restauration du microbiote a été observée chez les chevaux, à l'instar de ce qui est connu chez d'autres espèces. Nos résultats suggèrent que la concentration des bactéries ne devrait pas être recommandée dans la préparation des solutions FMT et que des recherches supplémentaires sont nécessaires pour améliorer les méthodes actuelles recommandées pour effectuer la FMT chez les chevaux.(Traduit par les auteurs).

Equine alveolar macrophages and monocyte-derived macrophages respond differently to an inflammatory stimulus.

Alveolar macrophages (AMs) are the predominant innate immune cell in the distal respiratory tract. During inflammatory responses, AMs may be supplemented by blood monocytes, which differentiate into monocyte-derived macrophages (MDMs). Macrophages play important roles in a variety of common equine lower airway diseases, including severe equine asthma (SEA). In an experimental model, an inhaled mixture of Aspergillus fumigatus spores, lipopolysaccharide, and silica microspheres (FLS), induced SEA exacerbation in susceptible horses. However, whether equine AMs and MDMs have differing immunophenotypes and cytokine responses to FLS stimulation is unknown. To address these questions, alveolar macrophages/monocytes (AMMs) were isolated from bronchoalveolar lavage fluid and MDMs derived from blood of six healthy horses. Separately, AMMs and MDMs were cultured with and without FLS for six hours after which cell surface marker expression and cytokine production were analyzed by flow cytometry and a bead-based multiplex assay, respectively. Results showed that regardless of exposure conditions, AMMs had significantly higher surface expression of CD163 and CD206 than MDMs. Incubation with FLS induced secretion of IL-1ß, IL-8, TNF-α and IFN-γ in AMMs, and IL-8, IL-10 and TNF-α in MDMs. These results suggest that AMMs have a greater proinflammatory response to in vitro FLS stimulation than MDMs, inferring differing roles in equine lung inflammation. Variability in recruitment and function of monocyte-macrophage populations warrant more detailed in vivo investigation in both homeostatic and diseased states.

Fecal prevalence of Clostridium innocuum DNA in healthy horses and horses with colitis.

This study compared the prevalence of C. innocuum DNA in the feces of healthy horses and horses with acute colitis. C. innocuum was identified in 22% (15/68) of colitis cases and 18% (12/68) of healthy horses (p = 0.416).

Fecal microbiota of horses with colitis and its association with laminitis and survival during hospitalization.

BACKGROUND: The association of microbiota with clinical outcomes and the taxa associated with colitis in horses remains generally unknown. OBJECTIVES: Describe the fecal microbiota of horses with colitis and investigate the association of the fecal microbiota with the development of laminitis and survival. ANIMALS: Thirty-six healthy and 55 colitis horses subdivided into laminitis (n = 15) and non-laminitis (n = 39, 1 horse with chronic laminitis was removed from this comparison) and survivors (n = 27) and nonsurvivors (n = 28). METHODS: Unmatched case-control study. The Illumina MiSeq platform targeting the V4 region of the 16S ribosomal RNA gene was used to assess the microbiota. RESULTS: The community membership (Jaccard index) and structure (Yue and Clayton index) were different (analysis of molecular variance [AMOVA]; P < .001) between healthy and colitis horses. The linear discriminant analysis effect size (LEfSe; linear discriminant analysis [LDA] >3; P < .05) and random forest analyses found Enterobacteriaceae, Lactobacillus, Streptococcus, and Enterococcus enriched in colitis horses, whereas Treponema, Faecalibacterium, Ruminococcaceae, and Lachnospiraceae were enriched in healthy horses. The community membership and structure of colitis horses with or without laminitis was (AMOVA; P > .05). Enterobacteriaceae, Streptococcus, and Lactobacillus were enriched in horses with laminitis (LDA > 3; P < .05). The community membership (AMOVA; P = .008) of surviving and nonsurviving horses was different. Nonsurviving horses had an enrichment of Enterobacteriaceae, Pseudomonas, Streptococcus, and Enterococcus (LDA >3; P < .05). CONCLUSION AND CLINICAL IMPORTANCE: Differences in the microbiota of horses with colitis that survive or do not survive are minor and, similarly, the microbiota differences in horses with colitis that do or do not develop laminitis are minor.

Acute diarrhea in horses: A multicenter Canadian retrospective study (2015 to 2019).

This study describes the clinicopathological findings, diagnostic approach, treatment, and factors associated with non-survival of diarrheic horses admitted to 4 Canadian university teaching hospitals between 2015 and 2019. A total of 300 horses, ≥1-year-old, with acute diarrhea were included and represented 1.6% (300/18 481; range: 0.7 to 3%) of admissions during that period, 70% of the horses survived to discharge. Testing for enteropathogens was limited to a single fecal culture for Salmonella spp. in most cases. An enteropathogen was identified in 14% (42/300) of the horses, but in the hospital with higher testing rates enteropathogens were detected in 29% (16/55) of cases. Neorickettsia risticii was the pathogen most frequently detected (31%, 32/102). Antimicrobial drugs and plasma were administered to 57 and 8% of the cases, respectively. Laminitis occurred in 24/298 (8%) of the horses. A multivariable regression model identified an association between non-survival of diarrheic horses and colic signs, increased heart rate, packed cell volume, creatinine concentration, and decreased total protein concentration. A standardized approach for pathogen detection in diarrheic horses is not consistent among Canadian veterinary teaching hospitals, and testing for known pathogens is limited. Signs of colic, severe dehydration, endotoxemia, and hypoproteinemia are associated with non-survival of diarrheic horses.

Diarrhée aiguë chez le cheval : une étude rétrospective canadienne multicentrique (2015 à 2019). Cette étude décrit les résultats clinicopathologiques, l'approche diagnostique, le traitement et les facteurs associés à la non-survie de chevaux diarrhéiques admis dans quatre hôpitaux universitaires canadiens entre 2015 et 2019. Un total de 300 chevaux, ≥1 an, atteints de diarrhée aiguë ont été inclus et représentaient 1,6 % (300/18 481; intervalle : 0,7 à 3 %) des admissions au cours de cette période. Soixante-dix pourcents des chevaux ont survécu jusqu'à leur congé. La recherche d'agents entéropathogènes était limitée à une seule culture fécale pour Salmonella spp. dans la plupart des cas. Un agent entéropathogène a été identifié chez 14 % (42/300) des chevaux, mais à l'hôpital avec des taux de dépistage plus élevés, des agents entéropathogènes ont été détectés dans 29 % (16/55) des cas. Neorickettsia risticii était l'agent pathogène le plus fréquemment détecté (31 %, 32/102). Des médicaments antimicrobiens et du plasma ont été administrés respectivement à 57 et 8 % des cas. Une fourbure est survenue chez 24/298 (8 %) des chevaux. Un modèle de régression multivarié a identifié une association entre la non-survie des chevaux diarrhéiques et les signes de coliques, l'augmentation de la fréquence cardiaque, l'hématocrite, la concentration de créatinine et la diminution de la concentration totale de protéines. Une approche normalisée pour la détection des agents pathogènes chez les chevaux diarrhéiques n'est pas uniforme dans les hôpitaux d'enseignement vétérinaires canadiens, et les tests pour les agents pathogènes connus sont limités. Des signes de coliques, de déshydratation sévère, d'endotoxémie et d'hypoprotéinémie sont associés à la non-survie des chevaux diarrhéiques.(Traduit par Dr Serge Messier).

Fecal Microbiota Comparison Between Healthy Teaching Horses and Client-Owned Horses.

The objective of this study was to compare the fecal microbiota of two healthy teaching horse herds with that of client-owned horses from the same geographic areas. The fecal microbiota of client-owned horses from Ontario Canada (n = 15) and Florida, USA (n = 11) was compared with that teaching horses from the University of Guelph, Ontario, Canada (n = 10) and the University of Florida, Florida, USA (n = 15). The fecal microbiota was characterized by sequencing of bacterial DNA using the V4 hypervariable region of the 16S rRNA gene. The diversity (inverse Simpson index) of the fecal microbiota was significantly higher in teaching than client owned horses from the same geographical area (P < .05). The community membership (Jaccard Index) and structure (Yue and Clayton index) of teaching horses was also significantly different from that of client owned horses from the same geographical area (AMOVA P < .001). The bacterial membership and structure of the fecal microbiota of Ontario and Florida teaching horses were significantly different, while the bacterial membership, but not the structure of Ontario and Florida client owned horses was significantly different (AMOVA P < .001). In all four groups of healthy horses, Lachnospiraceae, Ruminococcaceae, Bacteroidales, Clostridiales, and Treponema were detected in high relative abundance. The fecal microbiota of healthy horses from teaching herds kept in the same environment with identical management practices differs significantly from that of horses housed in different facilities with dissimilar management practices. Our results suggest an effect of the environment and management practices on the gastrointestinal microbiota. Researchers should attempt to include healthy horses from the same farm with similar management as control groups when comparing with diseased horses.

Infection of young foals with Equine Parvovirus-Hepatitis following a fatal non-biologic case of Theiler's disease.

Theiler's disease (TD) is a (sub-)acute hepatitis in adult horses and one of the most common causes of acute hepatic failure. Recent findings indicate that equine parvovirus hepatitis (EqPV-H) likely causes TD and that its transmission occurs via iatrogenic and/or natural routes. Following the death of an EqPV-H positive mare with TD, close-contact mares and foals in the same paddock were monitored to evaluate if there was any evidence of EqPV-H. For this purpose, the serum of close contact horses was examined 6 and 42 days after the mare's death for the presence of EqPV-H DNA and changes in liver-associated serum biochemical parameters. The foals had higher EqPV-H viral loads than the mares. Apart from the mare that was euthanized, none of the horses included in this study showed signs of severe disease and nor did they have particularly elevated liver enzymes. Nucleotide sequence analysis revealed no major differences between the viral DNA detected in the serum of the dead mare and any of the in-contact horses. In conclusion, our data confirmed previous findings that horizontal transmission of EqPV-H may occur through close contact between horses.

Serum IgM antibody response to Clostridioides difficile polysaccharide PS-II vaccination in pony foals.

OBJECTIVES: Clostridioides difficile (formerly Clostridium difficile) is associated with colitis in foals and mature horses. C. difficile exposes specific phosphorylated polysaccharides (PSs), named PS-I, PS-II and PS-III. These cell-surface PSs are potential vaccine targets, especially the hexasaccharide phosphate PS-II, that has been found in all C. difficile ribotypes examined. Since we previously identified anti-PS-II circulating antibodies in horses, we postulated that vaccinating foals with PS-II may prevent colonization by C. difficile. In this study, we aim to evaluate the IgM antibody responses in foals to PS-II. METHODS: To evaluate the reactogenicity and immunogenicity of C. difficile PS-II in foals, three-to four-month-old foals were vaccinated intramuscularly three times at intervals of three weeks with 100 µg/dose (3 foals) or 500 µg/dose (3 foals) of purified PS-II antigen with aluminum hydroxide adjuvant, or with a placebo preparation (2 foals) containing adjuvant alone. RESULTS: No injection site swelling, pain or fever was observed after vaccination. Two of the three foals receiving 100 µg/dose, and three out of three foals receiving 500 µg/dose of PS-II responded with increases in serum IgM antibodies. No control foals that received the placebo had IgM responses to PS-II. There was a trend towards a higher response rate in foals receiving 500 µg PS-II one week after second vaccination when compared to control foals and towards higher concentrations of serum IgM antibodies in foals receiving 500 µg PS-II. CONCLUSIONS: No adverse reactions were observed following vaccination with PS-II in foals; Serum IgM immune responses were induced by vaccination. A polysaccharide-based vaccine for C. difficile in horses deserves further investigation.

Real-Time PCR Differential Detection of Neorickettsia findlayensis and N. risticii in Cases of Potomac Horse Fever.

Potomac horse fever (PHF) is an acute and potentially fatal enterotyphlocolitis of horses with clinical signs that include anorexia, fever, diarrhea, and laminitis. Its incidence is increasing despite a commercially available vaccine. PHF is caused by Neorickettsia risticii, and the recently rediscovered and classified N. findlayensis. PHF diagnosis is currently accomplished using serology or nested PCR. However, both methods cannot distinguish the two Neorickettsia species that cause PHF. Further, the current N. risticii real-time PCR test fails to detect N. findlayensis. Thus, in this study, two Neorickettsia species-specific real-time PCR assays based on Neorickettsia ssa2 and a Neorickettsia genus-specific real-time PCR assay based on Neorickettsia 16S rRNA gene were developed. The ssa2 real-time PCR tests differentiated N. findlayensis from N. risticii in the field samples for which infection with either species had been verified using multiple other molecular tests and culture isolation, and the 16S rRNA gene real-time PCR detected both Neorickettsia species in the samples. These tests were applied to new field culture isolates from three Canadian provinces (Alberta, Quebec, Ontario) and Ohio as well as archival DNA samples from suspected PHF cases to estimate the prevalence of N. findlayensis in different geographic regions. The results suggest that N. findlayensis frequently causes PHF in horses in Alberta and Quebec. The development of these tests will allow rapid, sensitive, and specific diagnosis of horses presenting with clinical signs of PHF. These tests will also enable rapid and targeted treatment and help develop broad-spectrum vaccines for PHF.

Streptococcus equi culture prevalence, associated risk factors and antimicrobial susceptibility in a horse population from Colombia.

The objectives of this study were to determine the prevalence of S. equi in a horse population in Colombia, to determine the risk factors associated with its detection in the guttural pouches and to report the antimicrobial susceptibility of the isolates. Fifteen farms and 137 horses >6 months of age were enrolled. Sampling was randomly, stratified and proportional to the population size of each farm. The guttural pouch (GP) was swabbed via endoscopic guidance and culture was performed. DNA extraction and conventional PCR were performed in colonies compatibles with S. equi, the PCR products were sequenced and subjected to BLAST analysis. Antimicrobial drug sensitivity was assessed using an antimicrobial disc diffusion assay including penicillin, ceftiofur, trimethoprim-sulfamethoxasole (TMS), enrofloxacin and oxytetracycline. A mixed logistic regression model was constructed to evaluate risk factors associated with the presence of S. equi. The S. equi culture prevalence in the GP was 15%; 13.5 % for S. equi subsp. equi and 1.5% for S. equi subsp. zooepidemicus. History of travel was associated with the presence of S. equi, whereas every 1-year increase in age decreased the risk for S. equi detection in the GP. All isolates were susceptible to TMS, ceftiofur and penicillin, but resistant to enrofloxacin and oxytetracycline. S. equi is present in horses in Colombia, with a high prevalence and appear to be endemic in the tested population. Younger horses and horses with recent history of travelling had higher odds of testing positive for S. equi in swabs of the GP.

Serum haptoglobin concentration and liver enzyme activity as indicators of systemic inflammatory response syndrome and survival of sick calves.

BACKGROUND: Increased concentration of haptoglobin (Hp) in serum is associated with survival of critically ill humans and horses. High serum activity of liver-derived enzyme is associated with sepsis in children and foals. HYPOTHESIS/OBJECTIVES: Investigate whether admission serum Hp and glutamic dehydrogenase (GLDH) are associated with systemic inflammatory response syndrome (SIRS) and survival of sick calves. ANIMALS: One hundred two calves. METHODS: Retrospective cross-sectional study. Electronic medical records from all calves <30 days of age admitted to a teaching hospital for 8 years were reviewed. The signalment, clinicopathological findings, the presence of SIRS, final diagnosis, hospitalization time and outcome were recorded. A Cox proportional hazard ratio (HzR) were calculated to assess the association between clinicopathological variables and survival to discharge. RESULTS: Serum Hp concentrations were similar between SIRS (0.29 g/L; range, 0.05-3.6) and non-SIRS calves (0.22 g/L; range, 0-4.2; P = .62). GLDH activity was similar between SIRS (12 U/L; range, 1-1025) and non-SIRS calves (9 U/L; range, 2-137; P = .2). Absent suckle reflex (HzR: 6.44, 95% CI: 1.44-28.86), heart rate (HR) < 100 beats per minute (bpm; HzR: 12.2; 95% CI: 2.54-58.62), HR > 140 bpm (HzR: 3.59, 95% CI: 1.05-12.33), neutrophil count <1.7 × 109 /L (HzR: 7.36; 95% CI: 2.03-26.66) and increased gamma-glutamyl transferase activity (every 50-unit, HzR: 1.12; 95% CI: 1.03-1.21) were predictive of nonsurvival. CONCLUSIONS AND CLINICAL IMPORTANCE: The use of Hp and GLDH for prediction of survival in sick calves cannot be recommended at this time.