Atrial fibrillatory rate as predictor of recurrence of atrial fibrillation in horses treated medically or with electrical cardioversion.

BACKGROUND: The recurrence rate of atrial fibrillation (AF) in horses after cardioversion to sinus rhythm (SR) is relatively high. Atrial fibrillatory rate (AFR) derived from surface ECG is considered a biomarker for electrical remodelling and could potentially be used for the prediction of successful AF cardioversion and AF recurrence. OBJECTIVES: Evaluate if AFR was associated with successful treatment and could predict AF recurrence in horses. STUDY DESIGN: Retrospective multicentre study. METHODS: Electrocardiograms (ECG) from horses with persistent AF admitted for cardioversion with either medical treatment (quinidine) or transvenous electrical cardioversion (TVEC) were included. Bipolar surface ECG recordings were analysed by spatiotemporal cancellation of QRST complexes and calculation of AFR from the remaining atrial signal. Kaplan-Meier survival curve and Cox regression analyses were performed to assess the relationship between AFR and the risk of AF recurrence. RESULTS: Of the 195 horses included, 74 received quinidine treatment and 121 were treated with TVEC. Ten horses did not cardiovert to SR after quinidine treatment and AFR was higher in these, compared with the horses that successfully cardioverted to SR (median [interquartile range]), (383 [367-422] vs 351 [332-389] fibrillations per minute (fpm), P < .01). Within the first 180 days following AF cardioversion, 12% of the quinidine and 34% of TVEC horses had AF recurrence. For the horses successfully cardioverted with TVEC, AFR above 380 fpm was significantly associated with AF recurrence (hazard ratio = 2.4, 95% confidence interval 1.2-4.8, P = .01). MAIN LIMITATIONS: The treatment groups were different and not randomly allocated, therefore the two treatments cannot be compared. Medical records and the follow-up strategy varied between the centres. CONCLUSIONS: High AFR is associated with failure of quinidine cardioversion and AF recurrence after successful TVEC. As a noninvasive marker that can be retrieved from surface ECG, AFR can be clinically useful in predicting the probability of responding to quinidine treatment as well as maintaining SR after electrical cardioversion.

Disseminated Cryptococcus deuterogattii (AFLP6/VGII) infection in an Arabian horse from Dubai, United Arab Emirates / Infección diseminada por Cryptococcus deuterogattii (AFLP6/VGII) en un caballo árabe en Dubái, Emiratos Árabes Unidos

Background. During the past decades there has been an increase in cryptococcal infections caused by the basidiomycetous yeast species Cryptococcus gattii sensu lato, among humans and animals that live in endemic regions in Australia, Europe and the Americas. Unlike human cryptococcosis, little epidemiological data are available about C. gattii sensu lato infections in horses. Case report. A fatal case of a disseminated C. gattii sensu lato infection in an 11-year-old Arabian gelding imported from South Africa into the United Arab Emitares is reported. Tissue samples were studied by conventional mycology procedures and the obtained cryptococcal isolate was molecularly characterized by mating-type determination, amplified fragment length polymorphism (AFLP) fingerprinting, and multi-locus sequence typing (MLST). Phylogenetic analysis was performed to investigate the geographic origin of the cryptococcal isolate. The isolate was identified as Cryptococcus deuterogattii (AFLP6/VGII), mating-type α. Phylogenetic analysis showed that it was closely related to another C. deuterogattii isolate from the Middle East. Conclusions. A second case of a C. deuterogattii infection in the Middle East is described. It is likely that the horse acquired the infection in the Middle East, as the isolate is closely related to that of a recent human case from that region (AU)

Antecedentes. Durante las dos últimas décadas, las infecciones criptocócicas causadas por el hongo levaduriforme basidiomiceto Cryptococcus gattii sensu lato se han incrementado entre los seres humanos y los animales que viven en regiones endémicas de Australia, Europa y América. A diferencia de la criptococosis humana, existen muy pocos datos epidemiológicos disponibles sobre las infecciones por C. gattii sensu lato en los caballos. Caso clínico. Se expone el caso de una criptococosis diseminada fatal por C. gattii sensu lato en un caballo árabe castrado de 11 años de edad, importado desde Sudáfrica a los Emiratos Árabes Unidos. Las muestras de tejido analizadas por métodos microbiológicos convencionales permitieron el aislamiento de un criptococo que fue posteriormente caracterizado por técnicas moleculares para la determinación del tipo sexual, la obtención del perfil AFLP (amplified fragment length polymorphism) o polimorfismo de tamaño de fragmentos amplificados, y la tipificación por secuenciación multilocus (multi-locus sequence typing [MLST]). Se llevó a cabo un análisis filogenético para investigar el origen geográfico del criptococo aislado. Mediante PCR y AFLP el aislamiento fue identificado como Cryptococcus deuterogattii (AFLP6/VGII) y tipo sexual α. El análisis filogenético mostró que el aislamiento se encuentra muy próximo a otro único aislamiento de C. deuterogattii de Oriente Medio. Conclusiones. Este es el segundo caso descrito de infección por C. deuterogattii en Oriente Medio. Parece que el caballo adquirió la infección en aquella región, ya que el aislamiento muestra una relación muy próxima con otro de un caso reciente en un ser humano de esa región (AU)

Disseminated Cryptococcus deuterogattii (AFLP6/VGII) infection in an Arabian horse from Dubai, United Arab Emirates.

BACKGROUND: During the past decades there has been an increase in cryptococcal infections caused by the basidiomycetous yeast species Cryptococcus gattii sensu lato, among humans and animals that live in endemic regions in Australia, Europe and the Americas. Unlike human cryptococcosis, little epidemiological data are available about C. gattii sensu lato infections in horses. CASE REPORT: A fatal case of a disseminated C. gattii sensu lato infection in an 11-year-old Arabian gelding imported from South Africa into the United Arab Emitares is reported. Tissue samples were studied by conventional mycology procedures and the obtained cryptococcal isolate was molecularly characterized by mating-type determination, amplified fragment length polymorphism (AFLP) fingerprinting, and multi-locus sequence typing (MLST). Phylogenetic analysis was performed to investigate the geographic origin of the cryptococcal isolate. The isolate was identified as Cryptococcus deuterogattii (AFLP6/VGII), mating-type α. Phylogenetic analysis showed that it was closely related to another C. deuterogattii isolate from the Middle East. CONCLUSIONS: A second case of a C. deuterogattii infection in the Middle East is described. It is likely that the horse acquired the infection in the Middle East, as the isolate is closely related to that of a recent human case from that region.

Imaging diagnosis-aortic aneurysm and ureteral obstruction secondary to umbilical artery abscessation in a 5-week-old foal.

A 5-week-old foal was evaluated for fever and hematuria of 3 days duration. Cystoscopy localized the blood to be originating from the left ureter. Abdominal ultrasonography revealed left hydronephrosis, hydroureter, and omphaloarteritis of the left umbilical artery with abscess formation that communicated with an arterial structure. Computed tomography (CT) revealed a large aortic aneurysm within the center of the abscess. An exploratory celiotomy was performed and the infection was nonresectable. The prognosis for life was grave; therefore the colt was euthanized. Necropsy findings confirmed the antemortem diagnosis. Ultrasound and CT imaging in this case provided an accurate antemortem diagnosis.

Evaluation of squeeze-induced somnolence in neonatal foals.

OBJECTIVE: To test the hypothesis that application of a rope restraint device would result in behavioral, electroencephalographic, and humoral changes consistent with sleep and analgesia in neonatal foals. ANIMALS: 8 healthy neonatal foals. PROCEDURES: Following acclimatization to experimental conditions, each foal underwent a series of assessments before and during or at the end of a period of restraint via application of a restraint device (soft linen rope). Assessments included measurements of heart and respiratory rates, rectal temperature, and circulating ß-endorphin and steroid hormone concentrations and evaluations of mentation and body position (behavior), electroencephalographic patterns, and pain tolerance. RESULTS: All foals were lively with apparently normal behavior prior to restraint. During application of the restraint device, foals assumed lateral recumbency with relaxed, somnolent behavior. Heart and respiratory rates and rectal temperature uniformly decreased as a result of the procedure. Electroencephalographic recordings (completed for 3 foals only) revealed patterns consistent with slow wave sleep. Plasma ACTH, dehydroepiandrosterone sulfate, and androstenedione concentrations significantly increased during restraint, compared with prerestraint values. The foals' tolerance to noxious stimuli significantly increased during restraint; however, this was independent of the concentration of circulating ß-endorphin. CONCLUSIONS AND CLINICAL RELEVANCE: In neonatal foals, the evaluated form of restraint resulted in a decrease in heart and respiratory rates and rectal temperature. Squeeze-induced somnolence may resemble the effects of compression of the fetus in the birth canal and lead to inhibition of voluntary activity. Use of this technique to safely restrain neonatal foals during minor procedures warrants further evaluation.

Musculoskeletal Corynebacterium pseudotuberculosis infection in horses: 35 cases (1999-2009).

OBJECTIVE: To describe the clinical course and outcome in horses in which Corynebacterium pseudotuberculosis infections were associated with musculoskeletal disease and lameness. DESIGN: Retrospective case series. ANIMALS: 35 horses. PROCEDURES: Clinical and clinicopathologic data were collected from horses diagnosed with lameness associated with C pseudotuberculosis infection between 1999 and 2009. RESULTS: 32 (91.4%) horses had grade 4/5 lameness. Three (8.6%) horses had grade 5/5 lameness. Abscesses were diagnosed by clinical or ultrasonographic examination. Abscesses were located in the axillary or triceps region in 25 (71.4%) horses, the stifle region in 2 (5.7%), and the popliteal lymph node in 1 (2.9%). Diffuse lymphangitis was seen in 4 (11.4%) horses, osteomyelitis in 2 (5.7%) horses, and septic arthritis in 2 (5.7%) horses. Horses commonly had clinicopathologic abnormalities characterized by neutrophilia (96.4%), anemia (67.8%), hypoalbuminemia (66.6%), or hyperfibrinogenemia (42.8%). Treatment included surgical drainage of the abscess in 21 (60%) horses, performed under ultrasonography in 20 horses; anti-inflammatory medications in 34 (97.1 %) horses; and antimicrobials in 30 (85.7%) horses. CONCLUSIONS AND CLINICAL RELEVANCE: C pseudotuberculosis infection of the limbs in horses typically results in severe lameness but may have a favorable prognosis. The diagnosis may be challenging, and results of blood work consistent with inflammation are nonspecific, but anemia, hyperglobulinemia, and increased synergistic hemolysis inhibition titers are common. Ultrasonography may localize the lesions and facilitate surgical drainage to alleviate lameness. When C pseudotuberculosis musculoskeletal infection results in osteomyelitis or septic arthritis, the prognosis for survival is poor.

Efficacy of an avirulent live vaccine against Lawsonia intracellularis in the prevention of proliferative enteropathy in experimentally infected weanling foals.

OBJECTIVE: To determine the efficacy of an avirulent Lawsonia intracellularis vaccine in preventing proliferative enteropathy in weanling foals. ANIMALS: 12 healthy weanling foals. PROCEDURES: Foals were randomly assigned to a vaccinated, nonvaccinated, or control group. Vaccinated foals received an avirulent porcine L intracellularis frozen-thawed vaccine intrarectally 60 and 30 days prior to experimental challenge. On day 1, vaccinated and nonvaccinated foals were challenged via nasogastric intubation with a virulent heterologous isolate of L intracellularis. Control foals were not challenged. Clinical observation and ultrasonographic evaluation of the small intestine were performed, and body weight, serum concentration of total solids, fecal excretion of L intracellularis, and seroconversion were measured for each foal until day 56. Diseased foals were treated with antimicrobials and supportive care. RESULTS: None of the 4 vaccinated foals developed clinical disease following challenge with virulent L intracellularis. Three of 4 nonvaccinated foals developed moderate to severe clinical signs compatible with proliferative enteropathy, hypoproteinemia, and thickened small intestinal loops. Vaccinated foals had significantly less fecal shedding of L intracellularis than nonvaccinated foals. Serologic responses between vaccinated and nonvaccinated foals after challenge were similar. Control foals remained clinically unaffected with no evidence of fecal shedding and seroconversion. CONCLUSIONS AND CLINICAL RELEVANCE: Intrarectal administration of a commercial avirulent porcine vaccine against L intracellularis resulted in complete protection against proliferative enteropathy in the foals in this study and may also reduce environmental contamination with the organism on endemic farms.

Meningitis and meningoencephalomyelitis in horses: 28 cases (1985-2010).

OBJECTIVE: To describe clinical and clinicopathologic findings and outcome of horses with meningitis and meningoencephalomyelitis. DESIGN: Retrospective case series. ANIMALS: 28 horses. PROCEDURES: Medical records of horses admitted to the hospital during a 25-year period were reviewed. Horses with a definitive diagnosis of meningitis or meningoencephalomyelitis were included in this study. Information extracted from the medical records included signalment, history, reason for admission, clinical signs, results of clinicopathologic testing and diagnostic procedures, treatment, outcome, and necropsy findings. RESULTS: 22 horses had confirmed infectious disease (19 bacterial, 2 parasitic, and 1 fungal), 4 had suspected infectious disease on the basis of CSF cytologic examination findings, and 2 had noninfectious meningitis or meningoencephalomyelitis. Trauma of the head and vertebral column with disruption of the blood-brain barrier and local ascending or hematogenous spread were the most common routes of infection. Common neurologic signs included abnormal mental status, cranial nerve deficits, vestibular dysfunction, ataxia, tetraparesis, and apparent neck pain. Common hematologic abnormalities included leukocytosis, neutrophilia, lymphopenia, and hyperfibrinogenemia. Cytologic examination of CSF samples revealed moderate to marked suppurative inflammation. Mortality rate was 96.4%. Microbial culture of CSF yielded bacterial growth in 15 of 23 horses (before death [2 horses], after death [11], and both [2]). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that meningitis and meningoencephalomyelitis are uncommon disorders in horses. Infectious disease was more common than noninfectious disease. Local trauma, ascending infection, or hematogenous spread of infection were the most common causes of meningitis or meningoencephalomyelitis. Neurologic deficits, neutrophilia, lymphopenia, hyperfibrinogenemia, and CSF with neutrophilic pleocytosis were common findings in affected horses.

Peritonitis in horses: 55 cases (2004-2007).

Factors associated with the outcome of peritonitis in horses are seldom described. The objectives of this study were to determine the common clinical signs and clinicopathologic findings and to reveal prognostic factors associated with the outcome of peritonitis in equine patients. Data were examined in a retrospective manner in 55 horses diagnosed with and treated for peritonitis. The most common clinical and clinicopathologic findings were tachycardia (94%), increased amount of peritoneal fluid on ultrasound (84%), altered mucous membranes (82%), bacteria noted on the direct smear (67%), hyperfibrinogenaemia (58%) and left shift (40%). The most commonly isolated organism was E. coli (37%). Survival rates were as follow: 78% in the whole study, 81% in the abdominal lavage group, 93% in the medically and 46% in the surgically managed groups. Complications were more common in the non-survivor group (P < 0.001). Initial haematocrit and surgical interventions were strongly associated with non-survival in the multivariate logistic regression model (P = 0.049, OR: 1.07 and P = 0.01, OR: 9.87, respectively). Prognosis of peritonitis without gastrointestinal rupture depends on the initial hydration status, surgical interventions and development of secondary complications, while other clinical and clinicopathologic findings do not appear to correlate with survival. Prospective evaluation of hydration and perfusion parameters and abdominal lavage warrants further investigation.