Methicillin-resistant Staphylococcus spp. investigation in hospitalized horses and contacting personnel in a teaching veterinary hospital.

Staphylococci are well-known opportunistic pathogens associated with suppurative diseases in humans and animals. Antimicrobial resistance is an emergent threat to humans and animals worldwide. This study investigated the prevalence of methicillin-resistant Staphylococcus spp. (MRS) in hospitalized horses and contacting personnel (veterinarians and staff), and assessed possible interspecies transmission in a teaching veterinary hospital. Nasal swabs from horses (n = 131) and humans (n = 35) were collected. The microorganisms were identified by traditional biochemical tests and genotypic methods, i.e., PCR, internal transcript spacer PCR (ITS-PCR), and gene sequencing. Staphylococcal species were isolated in 18% (23/131) of the horses, of which 8% (11/131) were S. hyicus, 4 % (5/131) were S. aureus, 4% (5/131) were S. pseudintermedius, and 2% (2/131) were S. schleiferi subsp. coagulans. The mecA gene was detected in an S. pseudintermedius isolate. Staphylococcus spp. was isolated in 40% (14/35) of the human samples, all of which were S. aureus. In four samples of S. aureus, the clonal profile ST398 was identified; among them, a clonal similarity of 98.1% was observed between a horse and a contacting human. This finding supports the need for biosecurity measures to avoid the spread of multidrug-resistant staphylococci in humans and horses.

Flash Visual Evoked Potentials in Conscious Horses: A Preliminary Study.

The visual evoked potential (VEP) has many applications in veterinary neurology, but the test is not routinely used in a clinical setting. The aim of this study was to describe a reliable method for recording flash visual evoked potentials (F-VEPs) in nonsedated horses. F-VEPs were recorded from both eyes in 20 healthy and calm, adult horses. Recordings were accomplished without sedation, anaesthesia, or the use of mydriatic drugs. The mean and standard deviation of the latency of the most evident positive peak was 52.76±2.37 ms (P53). The mean latencies of the preceding and following negative peaks were 38.14±4.62 (N38) and 72.35±5.33 ms (N72), respectively. There were 2 mean peak-to-peak amplitudes (N38 - P53 and P53 - N72), and they were 11.85±6.21 and 22.81±11.50 µV, respectively. F-VEP was also recorded from 3 horses (6 eyes) before and during sedation with 2 doses each of xylazine (0.4 and 1.1 mg/kg) or detomidine (0.005 and 0.014 mg/kg). It was possible to obtain a reliable F-VEP with a P53 latency in horses without sedation that was similar to the P2 peak described in previous studies, and these data can be used in the future as a normal reference for comparisons in horses with different diseases using a similar methodology. Sedation affected the results by depressing peak amplitudes and increasing latencies or by completely obscuring any response. The exact impact of sedation on VEPs must be evaluated with much caution due to the small sample size.

Frequency of Equus caballus papillomavirus in equine aural plaques.

Despite the reported association between aural plaques and the presence of Equus caballus papillomavirus (EcPV), there are few data regarding the distribution of viral types in different geographic regions or possible correlations for different papillomaviruses and lesion characteristics. We detected the presence and frequency of EcPV (1-7) DNA in aural plaque biopsies of horses from different regions of Brazil and identified the patterns of these infections or coinfections and their possible association with lesion severity. A total of 108 aural plaque biopsies from horses in the 5 geopolitical regions of Brazil were examined. We performed PCR to detect EcPV DNA in the biopsies. At least 1 type of EcPV was detected in 97% of the samples. EcPV coinfection was observed in 59% of the samples. Compared to the other viruses, EcPV-4 was found at the highest frequency in coinfection (84%) or individually identified (32%). EcPV-2 and -7 were not detected. No significant association was found between lesion characteristics (type and distribution) and either the viral type detected or the presence of coinfection. EcPV is widely distributed in Brazil, both isolated and in coinfection; the viral type does not appear to influence the clinical characteristics of equine aural plaques.

Factors associated with equine aural plaque in Brazil.

BACKGROUND: Aural plaques can be found on the inner surfaces of one or both ears of horses. Despite their low malignancy, these lesions can sometimes cause discomfort and sensitivity in horses, and a loss in commercial value due to their aesthetic effect. There has been a study describing the epidemiological features and the clinical prevalence of equine aural plaques in Brazil. HYPOTHESIS/OBJECTIVES: To determine the clinical prevalence and selected associated factors of aural plaques. ANIMALS: In the study, 891 horses were assessed for aural plaques. The sample group had a median age of 5 years and comprised both sexes and various breeds from different regions of Brazil. METHODS: Horses were evaluated by a general observation of the body and a detailed observation of both ears. Data on the management system, characteristics of the lesions, the presence of ticks and ear grooming were collected for 109 clinically affected horses. An assessment of the frequency distribution of the disease and its characteristics was performed. Association tests were conducted to establish the relationships between the variables studied. RESULTS: In 85% (40 of 47) of farms assessed, at least one horse presented with aural plaques. In 14.8% (132 of 891) of the horses, lesions characteristic of aural plaque were detected. Significant associations between the prevalence of "coalescing" lesions and a "semi-intensive" management system and ear grooming were detected. CONCLUSIONS: The findings confirm the extensive distribution of this disease in Brazil and its association with several management factors.

Imiquimod treatment for Equus caballus papillomavirus infection in equine aural plaques.

BACKGROUND: Aural plaques are a dermatopathy associated with Equus caballus papillomavirus (EcPV). This disease affects horses of all ages, genders and breeds, and causes sensitivity of the ears. HYPOTHESIS/OBJECTIVES: The aim of this study was to evaluate the clinical efficacy of 5% imiquimod cream for the treatment of aural plaques and to compare the PCR detection of EcPV 3, 4, 5 and 6 before and after treatment. ANIMALS: Eight horses diagnosed with aural plaques (14 ears) were used. Three mares with unilateral aural plaques were used as untreated controls. METHODS: Imiquimod cream was applied every 48 h until complete resolution of the aural plaques was observed. Animals were evaluated clinically for 180 days after the end of treatment. PCR for detecting EcPV 3, 4, 5 and 6 was performed using aural plaque biopsies collected before and at 90 days after the end of treatment. RESULTS: Clinical resolution was observed in 93% of the treated ears. Imiquimod treatment promoted the clearance of EcPV in 71.4% of the treated ears. Clinical remission of the aural plaques and changes in EcPV DNA positivity between the first and second biopsies were not observed in the control group. In 75% of horses, sedation was required in order to carry out pretreatment cleaning. CONCLUSIONS: The results of this study support the hypothesis that 5% imiquimod cream may be used as an effective treatment for aural plaques in horses.

Brainstem auditory evoked potentials in horses / Potencial evocado auditivo de tronco encefálico em equinos

ABSTRACT: The brainstem auditory evoked potential (BAEP) evaluates the integrity of the auditory pathways to the brainstem. The aim of this study was to evoke BAEPs in 21 clinically normal horses. The animals were sedated with detomidine hydrochloride (0.013mg.kg-1 BW). Earphones were inserted and rarefaction clicks at 90 dB and noise masking at 40 dB were used. After performing the test, the latencies of waves (I, II, III, IV, and V) and interpeaks(I-III, III-V, and I-V) were identified. The mean latencies of the waves were as follows: wave I, 2.4 ms; wave II, 2.24 ms; wave III, 3.61ms; wave IV, 4.61ms; and wave V, 5.49ms. The mean latencies of the interpeaks were as follows: I-III, 1.37ms; III-V, 1.88ms; and I-V, 3.26ms. This is the first study using BAEPs in horses in Brazil, and the observed latencies will be used as normative data for the interpretation of tests performed on horses with changes related to auditory system or neurologic abnormalities.

RESUMO: O Potencial Evocado Auditivo de Tronco Encefálico (BAEP-Brainstem Auditory Evoked Potential) avalia a integridade das vias auditivas até o tronco encefálico. O objetivo da pesquisa foi padronizar o uso do BAEP em 21 equinos, sem aparente anormalidade auditiva. Os animais foram sedados com cloridrato de detomidina (0,013mg.kg-1 de PV). Foram utilizados fones de inserção,cliques de rarefação a 90 dB e um ruído de mascaramento de 40 dB. Foram identificadas as latências das ondas I, II, III, IV e V e dos interpicos I-III, III-V e I-V. As médias das latências das ondas foram: onda I 2,24ms; onda II 2,74ms; onda III 3,61ms; onda IV 4,61ms; e onda V 5,49ms. As médias das latências dos interpicos foram: I-III 1,37ms; III-V 1,88ms; e I-V 3,26ms. Este é o primeiro estudo utilizando o BAEP em equinos no Brasil e as latências observadas serão utilizadas como dados normativos para interpretação de exames de cavalos com anormalidades auditivas ou neurológicas.

Enteric Pathogens and Coinfections in Foals with and without Diarrhea.

Diarrhea is a major clinical problem affecting foals up to 3 months of age. The aim of this study was to identify enteric microorganisms involved in monoinfections and coinfections and the associated virulence factors in healthy and diarrheic foals. Diarrheic (D) (n = 56) and nondiarrheic (ND) foals (n = 60) up to three months of age were studied. Fecal samples were analyzed for identification of infectious agents (microbiological culturing, molecular techniques, and microscopic analyses). Escherichia coli fimH (30% versus 25%), Salmonella spp. (25% versus 7%), Strongyloides westeri (25% versus 25%), Clostridium perfringens type A (21% versus 10%), E. coli ag43 (20% versus 35%), Strongylus (11% versus 18%), and vapA-positive Rhodococcus equi (5% versus 2%) were the most frequent enteric pathogens detected in D and ND foals, respectively. The frequency of toxin A-positive C. perfringens was significantly increased in the D (p = 0.033) compared with the ND animals. R. equi strains harboring virulent plasmids were also identified (VapA 85-kb type I and VapA 87-kb type I) in D and ND foals. Coinfections were observed in 46% of the D and 33% of the ND foals. Our results demonstrate the great diversity of enteric pathogens, virulence factors, and coinfections involved in enteric infections of foals.