Detection of equine herpesvirus-1 (EHV-1) in urine samples during outbreaks of equine herpesvirus myeloencephalopathy.

BACKGROUND: Real-time PCR is the diagnostic technique of choice for the diagnosis and control of equine herpesvirus-1 (EHV-1) in an outbreak setting. The presence of EHV-1 in nasal swabs (NS), whole blood, brain and spinal cord samples has been extensively described; however, there are no reports on the excretion of EHV-1 in urine, its DNA detection patterns, and the role of urine in viral spread during an outbreak. OBJECTIVES: To determine the presence of EHV-1 DNA in urine during natural infection and to compare the DNA detection patterns of EHV-1 in urine, buffy coat (BC) and NS. STUDY DESIGN: Descriptive study of natural infection. METHODS: Urine and whole blood/NS samples were collected at different time points during the hospitalisation of 21 horses involved in two EHV-1 myeloencephalopathy outbreaks in 2021 and 2023 in Spain. Quantitative real-time PCR was performed to compare the viral DNA load between BC-urine samples in 2021 and NS-urine samples in 2023. Sex, age, breed, presence of neurological signs, EHV-1 vaccination status and treatment data were recorded for all horses. RESULTS: A total of 18 hospitalised horses during the 2021 and 2023 outbreaks were positive for EHV-1, and viral DNA was detected in urine samples from a total of 11 horses in both outbreaks. Compared with BC samples, DNA presence was detected in urine samples for longer duration and with slightly higher concentration; however, compared with NS, detection of EHV-1 in urine was similar in duration with lower DNA concentrations. MAIN LIMITATIONS: Limited sample size, different sampling times and protocols (BC vs. NS) in two natural infection outbreak settings. CONCLUSIONS: EHV-1 was detected in the urine from naturally infected horses. Urine should be considered as complimentary to blood and NS in diagnosis of EHV-1 infection.

HISTORIAL: PCR en tiempo real es la técnica diagnostica de preferencia para el diagnóstico y control del herpes virus equino­1 (EHV­1) en una situación de brote. La presencia de EHV­1 en torulas nasales (TN), muestras de sangre entera, cerebro, y medula espinal ha sido descrita en forma extensa; sin embargo, no hay informes de excreción de EHV­1 en orina, la detección del patrón de ADN, y el rol de la orina en la propagación vírica durante un brote. OBJETIVOS: Determinar la presencia de ADN de EHV­1 en muestras de orina durante un brote infeccioso natural y comparar los patrones de detección de ADN de EHV­1 en orina, capa leucocitaria (CL) y TN. DISEÑO DEL ESTUDIO: Estudio prospectivo en una infección natural en caballos hospitalizados. MÉTODOS: Muestras de orina y sangre entera/TN fueron recolectadas a distintos tiempos durante la hospitalización de veintiún caballos involucrados en dos brotes de mielo encefalopatía por EHV­1 en 2021 y 2023 en España. PCR a tiempo real cuantitativo fue llevado a cabo para comparar la carga de ADN viral entre muestras de CL­orina en 2021 y muestras TN­orina en 2023. Sexo, edad, raza, presencia de síntomas neurológicos, estatus de vacunación y datos de tratamiento fueron anotados para todos los caballos. RESULTADOS: Un total de diez y ocho caballos hospitalizados durante los brotes de 2021 y 2023 resultaron positivos a EHV­1, y ADN viral fue detectado en muestras de orina en un total de 11 caballos de ambos brotes. En comparación a muestras de CL, la presencia de AND fue detectado por mas largo tiempo y con una concentración ligeramente mas alta; sin embargo, en comparación a TN, la detección de EHV­1 en orina fue similar en tiempo pero demostró menor concentración de ADN. LIMITACIONES PRINCIPALES: Tamaño de muestra limitado, tiempos de muestreo diferentes, y de protocolos (CL vs. TN) en dos situaciones de brotes naturales. CONCLUSIONES: Se detecto EHV­1 en orina de caballos infectados naturalmente. La recolección, no invasive, de orina debería considerarse como un complemento a las muestras de sangre y TN en el control de caballos infectados en situaciones de brote.

Demographic, preoperative and anaesthesia-related risk factors for unsatisfactory recovery quality in horses undergoing emergency abdominal surgery.

OBJECTIVE: To determine demographic, preoperative and anaesthesia-related variables that may be associated with unsatisfactory recovery quality in horses undergoing emergency abdominal surgery (colic) in an equine teaching hospital. STUDY DESIGN: Retrospective case series. ANIMALS: A total of 313 horses. METHODS: The anaesthetic records of horses admitted for surgical treatment of colic between 2005 and 2018 were examined. Overall quality of recovery was assessed as dangerous, poor, fair, good or excellent. The following categories were constructed as a dichotomic variable: unsatisfactory recovery (poor and dangerous recoveries) and satisfactory recovery (excellent, good and fair recoveries). Univariable and multivariable analyses were performed to evaluate the association between all studied variables and recovery. RESULTS: All recoveries were unassisted. Unsatisfactory recovery quality totalled 17.2% (3.5% and 13.7% were dangerous and poor recoveries, respectively), whereas satisfactory recoveries totalled 82.8% (26.2%, 40.9% and 15.7% were fair, good and excellent recoveries, respectively). Univariable analysis showed that unsatisfactory recoveries were associated with high preoperative packed cell volume, pain behaviour, poor premedication and induction quality, high intraoperative mean heart rate, low mean arterial blood pressure, dobutamine dose ≥1.5 µg kg-1 minute-1, non-administration of romifidine, long anaesthesia time and prolonged time to stand. The multivariable model showed that factors strongly associated with unsatisfactory recovery quality were dobutamine dose ≥1.5 µg kg-1 minute-1 [adjusted odds ratio (AOR) = 6.60; 95% confidence interval (CI), 2.91-14.96], poor premedication quality (AOR=4.60; 95% CI, 1.73-12.23) and a time to stand > 70 minutes (AOR=2.59; 95% CI, 1.13-5.91). CONCLUSIONS AND CLINICAL RELEVANCE: Our study shows that high dobutamine requirements, poor premedication quality and a prolonged time to stand are risk factors for unsatisfactory recovery quality in horses undergoing anaesthesia for colic surgery. Addressing these factors may enable clinicians to improve the quality of recovery phase.

Cardiorespiratory, Sedative and Antinociceptive Effects of a Medetomidine Constant Rate Infusion with Morphine, Ketamine or Both.

Standing surgery under sedation reduces anesthetic-related mortality in horses. Medetomidine, alone and combined with morphine in a constant rate infusion (CRI), has been described for standing surgery but their cardiorespiratory, sedative and antinociceptive effects have never been compared. The addition of ketamine could improve analgesia in these procedures with minimal cardiorespiratory consequences. The objectives were to compare the cardiorespiratory effects, quality of sedation, antinociception and ataxia produced by administration of a medetomidine-based CRI with morphine, ketamine or both, in standing horses. A prospective, blind, randomized crossover, experimental design with six healthy adult horses was performed, in which four treatments were administered to all horses with at least two weeks of washout period: medetomidine (M); medetomidine and ketamine (MK); medetomidine and morphine (MMo); and medetomidine, morphine and ketamine (MMoK). Dosages were the same in all treatment groups: medetomidine at 5 µg/kg bwt followed by 5 µg/kg bwt/h, ketamine at 0.4 mg/kg/h and morphine at 50 µg/kg bwt, followed by morphine 30 µg/kg bwt/h. Drug infusions were maintained for 120 min. Cardiorespiratory variables, sedation degree and antinociceptive effects were evaluated during the procedure. All combinations produced similar sedation and antinociceptive effects and no clinically relevant alterations in cardiorespiratory variables occurred. Medetomidine CRI combined with morphine, ketamine or both are suitable and safe protocols for standing sedation in horses and the addition of morphine and/or ketamine did not cause any negative effect but no improving effect on sedation and antinociception was detected.

Accelerated Idioventricular Rhythm Associated With Isoflurane Administration in a Foal: A Case Report.

A 2-day-old filly was referred to the hospital with abdominal pain and constipation. The foal presented tachycardia, tachypnea, hypoxemia, hyperlactatemia, and abdominal distension. Meconium impaction was diagnosed, and the filly underwent abdominal surgery. Diazepam and butorphanol were administered for anesthesia premedication, but sedative effects were mild. Xylazine was used to enhance sedation and ketamine was subsequently administered for induction. The foal showed swallow reflex and head movement when intubation was attempted. Consequently, isoflurane on oxygen was provided via an anesthetic face mask. After intubation, the foal was connected to the anesthetic machine and monitored. The electrocardiogram revealed accelerated idioventricular rhythm, characterized by atrioventricular isorhythmic dissociation with monomorphic wide QRS complexes. Lidocaine was administered but the arrhythmia persisted during anesthesia and was spontaneously corrected once the isoflurane was discontinued at the end of the procedure. The foal recovered from anesthesia without complications and no further cardiac events were observed before the patient being discharged. Accelerated idioventricular rhythm likely resulted from administration of isoflurane to a foal presenting hypoxemia, a condition that exacerbates the risk of arrhythmia. Proper management of this abnormal rhythm is crucial as inappropriate treatments may worsen the arrhythmia.