真菌性乳房炎病原菌的分离鉴定及其致病性研究

本研究针对天津地区使用多种常规药物治疗均无效的乳房炎患牛,无菌采集奶样进行真菌病原分离鉴定及致病性试验, 经鉴定其病原菌为白色念珠菌和新型隐球菌,其对试验动物具有较强的致病力。本研究结果为更好地了解天津市及周边地区奶牛感染真菌的情况,进而采取有效的防治措施提供了一定的理论依据。     

新生隐球菌病研究进展

隐球菌是条件致病性深部真菌,易发于细胞免疫功能受损的人群.新生隐球菌是隐球菌属的重要致病菌,属环境腐生菌,可从土壤和鸽粪中分离到,并被认为是人和动物最主要的传染源.医学方面,近年来由新生隐球菌引起的感染有逐渐增多的趋势,主要引起人的脑膜炎和肺炎.动物医学方面,可引起马的呼吸道病、牛羊的乳腺炎.鸽是隐球菌的自然宿主,但并不引起发病.该文从隐球菌病的病原特征、分类、毒力因子、致病性等生物学特性进行了概述,并对人和动物新生隐球菌病的传染和流行的基本环节、发病机制、临床表现、防治等方面的研究进展进行了综述.     

Cerebral infarction and meningoencephalitis following hot-iron disbudding of goat kids

CASE HISTORY: Twelve of 150 goat kids, 4–10 days old, died 3 days after disbudding with a hot iron. Another 18 kids had been ill the previous day but survived following antibiotic therapy. Five of the dead kids were necropsied.

PATHOLOGICAL FINDINGS: There was necrosis and haemorrhage of the skin, subcutaneous tissues and frontal bone at disbudding sites in all five kids examined post mortem. Beneath disbudding sites in 4/5 kids there were bilateral, dark red, often cavitated areas of necrosis extending deep into the frontal cortex of the brain. Histologically, these areas consisted of coagulation necrosis, haemorrhage, vascular thrombosis and suppurative inflammation. Numerous bacteria, predominantly large Grampositive rods, were present in the necrotic brain tissue. In the remaining kid, bilateral areas of yellow discolouration and flattening of gyri in frontal lobes corresponded histologically to extensive polioencephalomalacia. A mixed growth of aerobes and anaerobes was cultured from the brain of one kid with suppurative lesions.

CLINICAL RELEVANCE: Thermal disbudding of neonatal kids is widely practised in dairy goat herds and is considered the method of choice for disbudding in New Zealand. However, the skull of goat kids is much thinner than that of calves and the safety margin for thermal injury to the brain is markedly reduced. This report highlights the risks associated with the technique and its potential as a welfare issue.     

Effect of injection site on the bioavailability of an oxytetracycline formulation in ruminant calves

The oxytetracycline (OTC) disposition was studied in a group of six calves following the administration of an oxytetracycline‐10 per cent formulation (i) intravenously (i.v.), (ii) subcutaneously (s. c.) in the lateral neck, and intramuscularly (i. m.) in (iii) the lateral neck, (iv) the shoulder (M. triceps brachii), and (v) the buttock (M. semitendineus). The dose levels used for the intravenous route and other routes were respectively 17.0 ± 2.3 and 18.3 ± 1.25 mg OTC/kg. The peak OTC concentrations (Cmax) were achieved with the s. c. and i. m. routes between 4 and 8 hours after injection, the highest being found after application in the shoulder (Cmax:6.9 ± 0.82 μg/ml plasma). The Cmax for the s.c. and other i.m. routes of application was similar to each other, ranging from 5.0 to 5.5 μg/ml plasma. For different points in time after injection the partial bioavailability was calculated. At 52 h post injection (p.i.) maximal bioavailability was observed for the i.m. shoulder route, viz. 98.1 ± 7.0 per cent of the administered dose, while at 76 h p.i. similar bioavailabilities were achieved for the i.m. neck and shoulder route, namely 93.3 ± 8.9 and 99.4 ± 4.2 per cent, respectively. The lowest bioavailability (83.1 ± 13.4 per cent) was obtained following the i.m. buttock route at 76 p.i.

An obvious irritating effect was observed after s.c. application in the neck an di.m. injection in the buttock, which had disappeared at 5 days p.i. It is assumed that the longer persistence of OTC in plasma resulting with the latter two routes of administration was due to this irritation effect.     

A multiplex quantitative real-time polymerase chain reaction panel for detecting neurologic pathogens in dogs with meningoencephalitis

Meningoencephalitis (ME) is a common inflammatory disorder of the central nervous system in dogs. Clinically, ME has both infectious and non-infectious causes. In the present study, a multiplex quantitative real-time polymerase chain reaction (mqPCR) panel was optimized for the detection of eight canine neurologic pathogens (Blastomyces dermatitidis, Cryptococcus spp., Neospora caninum, Borrelia burgdorferi, Bartonella spp., Toxoplasma gondii, Ehrlichia canis, and canine distemper virus [CDV]). The mqPCR panel was subsequently applied to 53 cerebrospinal fluid (CSF) samples collected from dogs with ME. The analytic sensitivity (i.e., limit of detection, expressed as molecules per 1 µL of recombinant vector) was 3.8 for CDV, 3.7 for Ehrlichia canis, 3.7 for Bartonella spp., 3.8 for Borrelia burgdorferi, 3.7 for Blastomyces dermatitidis, 3.7 for Cryptococcus spp., 38 for Neospora caninum, and 3.7 for Toxoplasma gondii. Among the tested CSF samples, seven (15%) were positive for the following pathogens in decreasing order of frequency: Cryptococcus spp. (3/7), Blastomyces dermatitidis (2/7), and Borrelia burgdorferi (2/7). In summary, use of an mqPCR panel with high analytic sensitivity as an initial screen for infectious agents in dogs with ME could facilitate the selection of early treatment strategies and improve outcomes.     

Detection of blood‐brain barrier dysfunction using advanced imaging methods to predict seizures in dogs with meningoencephalitis of unknown origin

BackgroundThe blood‐brain barrier (BBB), which separates the intravascular and neuropil compartments, characterizes the vascular bed of the brain and is essential for its proper function. Recent advances in imaging techniques have driven the development of methods for quantitative assessment of BBB permeability.Hypothesis/ObjectivesPermeability of the BBB can be assessed quantitatively in dogs with meningoencephalitis of unknown origin (MUO) and its status is associated with the occurrence of seizures.AnimalsForty dogs with MUO and 12 dogs without MUO.MethodsRetrospective, prospective cohort study. Both dynamic contrast enhancement (DCE) and subtraction enhancement analysis (SEA) methods were used to evaluate of BBB permeability in affected (DCE, n = 8; SEA, n = 32) and control dogs (DCE, n = 6; SEA, n = 6). Association between BBB dysfunction (BBBD) score and clinical characteristics was examined. In brain regions where BBBD was identified by DCE or SEA magnetic resonance imaging (MRI) analysis, immunofluorescent staining for albumin, glial fibrillary acidic protein, ionized calcium binding adaptor molecule, and phosphorylated mothers against decapentaplegic homolog 2 were performed to detect albumin extravasation, reactive astrocytes, activated microglia, and transforming growth factor beta signaling, respectively.ResultsDogs with BBBD had significantly higher seizure prevalence (72% vs 19%; P = .01) when compared to MUO dogs with no BBBD. The addition of SEA to routine MRI evaluation increased the identification rate of brain pathology in dogs with MUO from 50% to 72%.Conclusions and Clinical ImportanceImaging‐based assessment of BBB integrity has the potential to predict risk of seizures in dogs with MUO.     

Adipsia and hypernatraemia in a dog with focal hypothalamic granulomatous meningoencephalitis

A 7-year-old Doberman was presented with a history of progressive neurological disease of 4 weeks duration. Initially there were episodes of aimless wandering and uncharacteristic aggression, however, the dog was obtunded at presentation. Serum biochemical analysis revealed profound hypernatraemia and moderate hyperproteinaemia. Despite correction of the hypernatraemia by the infusion of hypotonic fluids, the dog continued to periodically exhibit pacing and head pressing. A patchy, ill-defined contrast-enhancing area was evident in the ventral midbrain on computed tomography of the brain. Analysis of the cerebrospinal fluid revealed a mild increase in protein concentration, positive Pandy's test and mild pleocytosis. Because of the poor prognosis, euthanasia and necropsy were performed. Histopathological analysis of the brain revealed a severe focal meningoencephalitis affecting hypothalamic nuclei and mammillothalamic tracts. Destruction of osmoreceptors in the hypothalamus responsible for recognition of thirst is believed to have resulted in adipsia and subsequent hypernatraemia.