Assessment of the inter-rater agreement of corneal cytology and culture findings in canine ulcerative keratitis.

OBJECTIVES: To assess the inter-rater agreement of corneal cytology findings in canine ulcerative keratitis by veterinary surgeons of different training levels and the agreement of corneal cytology with culture. MATERIALS AND METHODS: Dogs with progressive ulcerative keratitis were prospectively recruited for corneal cytology and culture. Corneal cytology slides were reviewed by veterinary surgeons of different training levels (three general practitioners, three ophthalmologists and three pathologists). The inter-rater agreement of cytology findings and agreement of cytology with culture was assessed using the kappa measure of agreement. RESULTS: The study included 145 corneal cytology samples from 143 dogs (145 eyes) with progressive ulcerative keratitis. Positive cultures were obtained from 81 of 145 (56%) eyes. The most commonly isolated pathogens were Streptococcus canis, Pseudomonas aeruginosa and Staphylococcus pseudintermedius. The results demonstrated increased inter-rater agreement of corneal cytology and increased agreement with culture with increased ocular pathology expertise (pathologists > ophthalmologists > general practitioners). CLINICAL SIGNIFICANCE: This study provides important information about the diagnostic value of corneal cytology in canine ulcerative keratitis and the most common pathogens involved in such cases in the UK. Based on the results of this study, cytology findings should be interpreted in conjunction with the expertise of the observer. For maximal pathogen identification, both cytology and culture should be considered.

Spinal Cord Compression in a Horse due to a Granular Cell Variant of Neurofibroma.

A neurofibroma of granular cell subtype is described in a 7-year-old horse. The horse had a 3-month history of ataxia affecting the forelimbs and hindlimbs, suggesting a C1-C6 neuroanatomical localization. Post-mortem examination revealed an intradural mass arising from the right sixth cervical spinal nerve and compressing the spinal cord. Histologically, the mass was composed largely of wavy spindle cells (a mixture of Schwann cells, perineurial cells and fibroblasts) intimately associated with ropy collagen fibres. Approximately 25% of the spindle cells were swollen and contained densely-packed, eosinophilic and periodic acid-Schiff-positive cytoplasmic granules. Immunohistochemistry for S100 and glial fibrillary acidic protein antigens labelled a proportion of neoplastic cells, while the cytoplasmic granules were positive for S100 and neuron specific enolase. This is the first report of a neurofibroma with granular cell differentiation in an animal. Granular cell differentiation in other peripheral nerve sheath tumours of animals is briefly discussed.

High prevalence of Seoul hantavirus in a breeding colony of pet rats.

As part of further investigations into three linked haemorrhagic fever with renal syndrome (HFRS) cases in Wales and England, 21 rats from a breeding colony in Cherwell, and three rats from a household in Cheltenham were screened for hantavirus. Hantavirus RNA was detected in either the lungs and/or kidney of 17/21 (81%) of the Cherwell rats tested, higher than previously detected by blood testing alone (7/21, 33%), and in the kidneys of all three Cheltenham rats. The partial L gene sequences obtained from 10 of the Cherwell rats and the three Cheltenham rats were identical to each other and the previously reported UK Cherwell strain. Seoul hantavirus (SEOV) RNA was detected in the heart, kidney, lung, salivary gland and spleen (but not in the liver) of an individual rat from the Cherwell colony suspected of being the source of SEOV. Serum from 20/20 of the Cherwell rats and two associated HFRS cases had high levels of SEOV-specific antibodies (by virus neutralisation). The high prevalence of SEOV in both sites and the moderately severe disease in the pet rat owners suggest that SEOV in pet rats poses a greater public health risk than previously considered.