Christina McCowan

A 9-year-old, spayed, female Golden Retriever presented with an 18-month history of small spots of opacification on the left cornea, a 3-4-month history of a raised spot on the left cornea, and a watery left eye. As a puppy, the dog had sustained an injury to the left cornea. Self-limiting, presumed papillomaviral warts were diagnosed on the face when the dog was 8 months old. A full ophthalmic examination revealed a well-circumscribed, pigmented, raised mass immediately adjacent to three smaller pink masses on the left cornea. The corneal tumour was resected by superficial keratectomy. The cornea was treated with topical peginterferon alfa-2a drops post-operatively. The mass was histologically diagnosed as an incompletely excised corneal pigmented squamous cell carcinoma (pSCC) displaying both exophytic growth and superficial stromal invasive characteristics and fine granular brown melanin pigment within the cytoplasm of neoplastic cells. Superficial cells showed evidence of papillomavirus-induced cell changes including enlarged cells with blue-grey cytoplasm and darkly basophilic keratohyalin granules. Canine papillomavirus type 17 (CPV17) DNA sequences were amplified from the carcinoma by PCR using consensus papillomavirus primers. Primary corneal pigmented squamous cell carcinoma with concurrent canine papillomavirus type 17 infection. Tumour recurrence was observed 2 years 9 months after surgery. Topical peginterferon alfa-2a drops were recommenced and superficial keratectomy surgery was repeated with concurrent adjunctive strontium 90 plesiotherapy. At the time of writing, the left cornea has healed well with mild fibrosis and vascularisation continuing to reduce. This is the first report of a pSCC of the cornea in any veterinary species. Prominent papillomaviral cytopathology was visible in the corneal pSCC, and PCR confirmed the presence of CPV17.This report expands the differential diagnoses for pigmented corneal masses in dogs. It highlights the importance of obtaining a histopathological diagnosis for pigmented corneal lesions, as the clinical disease course, prognosis and treatment options vary between lesions of different aetiologies. Corneal SCC is locally invasive and can recur without complete excision. Early surgical intervention with clean margins can be curative and restore corneal clarity, vision and patient comfort.

Objective: To evaluate the retina and optic nerve head (ONH) in canine eyes predisposed to glaucoma using optical coherence tomography (OCT).Animals: Twenty‐five eyes (24 dogs).Methods: Measures of peripapillary retinal, retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) thickness and ONH parameters were obtained in vivo by OCT of the unaffected eye in dogs diagnosed with unilateral primary glaucoma (predisposed; n = 12) and compared with measures of healthy control eyes (normal; n = 13). Repeatability and intrarater reliability were explored using intraclass correlation coefficients (ICC).Results: Compared to normal eyes, predisposed eyes had a thinner retina in the temporal (P = 0.005), inferior quadrants (P = 0.003), and decreased inner retinal thickness (superior: P = 0.003, temporal: P = 0.001, inferior: P < 0.001, nasal: P = 0.001). Predisposed eyes had a thinner RNFL compared to normal eyes (P = 0.005), and when analyzed in quadrants, it was thinner in the superior (P < 0.001), temporal (P = 0.034), and nasal quadrants (P = 0.001). Repeatability (ICC 0.763‐0.835) and intrarater reliability (ICC 0.824‐0.942) were good to excellent for measures of retinal thickness and adequate for RNFL measurements (ICC 0.701‐0.798). Reliable measurements of optic disk area were obtained and were similar between groups (P = 0.597). Measurements of parameters relying on automated software detection (GCC, optic cup, optic rim) had inadequate repeatability and reliability.Conclusion: Statistically significant differences in retinal and RNFL thicknesses were identified in normal and predisposed eyes. Reliable and consistent measurements of variables with manual adjustment of software detected parameters were obtained. Validation of OCT as a diagnostic tool for clinical assessment in canine glaucoma is warranted.

Aims: The objectives of this study were to estimate the prevalence of digital dermatitis (DD) in Victoria, Australia, and to investigate which organisms are consistent with typical DD lesions. The prevalence and causative pathogens of DD are not clear yet in Australia and this paper is one of the first to explore these questions in this country.Methods: Examination and sampling of limbs was undertaken at three knackeries in Victoria, Australia. Limbs were classified as normal (N), active DD‐lesion (A), dried or chronic DD‐lesion (D) or suspected case of DD (S). A total of 823 cows were examined. Six skin biopsies were taken at each knackery, from which DNA was extracted for diversity profiling. Histochemical staining of samples was performed on eight of the skin biopsies.Results: DD was detected in 29.8% of all cows. The prevalence of DD was significantly higher in dairy cows (32.2%) than in beef cows (10.8%). The differential abundance of Treponema‐species was significantly increased in dried lesions, compared with the normal skin biopsies. Actinobacteria, Proteobacteria, Firmicutes and Tenericutes were found to be significantly different in abundance in the DD lesions compared with normal skin biopsies. Silver staining of samples showed only mild inflammation and in two samples organisms with morphology consistent with Spirochaetes were detected.Conclusions: The calculated prevalence indicates that DD is present in Victoria, Australia. The results of diversity profiling showed that the presence of Treponema‐species was significantly different between the samples of DD lesions and normal skin.

A novel Group A rotavirus, first identified clinically in racing, feral and fancy pigeons in Western Australia, had spread throughout Australia by March 2017. In December 2016, the putative index case of rotavirus in racing pigeons in the state of Victoria was confirmed at a regional bird sale, with rapid spread to peri‐urban Melbourne, the capital city. A survey sent to approximately 400 Victorian pigeon fanciers identified eight (of 85 respondents) with a confirmed rotavirus infection in their loft(s). If a fancier had purchased live birds, either from the regional sale or from another source, there was a 13% to 38% increased likelihood of the loft subsequently being confirmed rotavirus‐positive. An increased loft‐level risk of rotavirus was also positively associated with the number of neighboring lofts within a five‐kilometre radius of a home loft. It was concluded that rotavirus was primarily transmitted beyond the Victorian index case through the movement of live birds into a loft, either deliberately through bird purchase and/or inadvertently through the entry of pigeons from neighboring lofts. As pigeon racing inherently requires consistent contact between birds from different lofts, vaccination is recommended as a primary method of rotavirus control in this unique industry.

Aim: To describe the development and initial validation of a questionnaire measuring functional vision in dogs.Methods: A 17‐item survey was designed to quantify functional vision in dogs. The Vision Impairment Score (VIS) was determined by summing responses to each question. Questions were assigned to one of five subcategories: overall vision, daily activities, peripheral vision, near vision, and distance vision. Content validity was established during development phases, and construct validity via comparing results of known groups (blind vs sighted; normal vs impaired vision; surgery to improve vision vs nonrestorative surgery), and through factor analysis. Concurrent criterion validity was determined with use of a validated health‐related quality‐of‐life (HRQL) assessment tool. Reliability and responsiveness assessments were investigated using intraclass correlation coefficient (ICC) and effect size (ES), respectively.Results: Responses (221) from 201 dog owners were included. Compared to sighted dogs (n = 153), blind dogs (n = 48) had a higher VIS and greater impairment in all subcategories. Among sighted dogs, a higher VIS was obtained in dogs with low vision compared to those with normal vision (P < 0.001). A higher VIS was associated with poorer HRQL (P < 0.001). Perfect reliability was obtained for 6/17 questions, and excellent reliability for 11/17 questions (intraclass correlation 1.0 and >0.9, respectively), and the VIS was highly responsive to therapeutic intervention (effect size 1.46).Conclusion: Results suggest the VIS may be clinically useful in assessing and obtaining a quantifiable measure of functional vision in dogs. Ongoing validation of the tool for clinical use is needed.

Objectives To describe preliminary use of a forced‐choice preferential looking task for the clinical assessment of vision in dogs. Materials and Methods The vision of 18 pet dogs was investigated in two separate studies using a forced‐choice preferential looking task: multiple observers watched eye, head and body movements on video recordings to identify cues suggesting when a dog had seen the feature of interest. Human observer reliability was determined using eight dogs and computer‐generated stimuli. Visual acuity was assessed using computer‐generated grating stimuli: in real‐time, an observer watched each dog's eye movement patterns and behaviour to decide whether each grating was seen. Stimuli were presented in a step‐wise manner and were controlled by the observer. Acuity was estimated as the highest spatial frequency the dog was determined to have seen. Results Median estimated visual acuity was better at 1 m compared to that at 3 m. Average test time was longer at a 3‐m distance than at 1 m. Inter‐ and intra‐observer reliability was better from 1 m than from 3 m. Clinical Significance Preliminary use of a forced‐choice preferential looking task for measurement of visual acuity in dogs has potential use as a clinical tool for the assessment of vision in dogs.

Rotaviruses are well‐known causative agents of enteric disorders in humans and other mammals, but little is known about their virulence and pathogenic role in pigeons and other birds. Starting in summer 2017, a series of outbreaks of an acute disease with high mortalities was reported in domestic pigeons in Germany, Belgium and Denmark. The clinical picture was characterized by diarrhea, vomiting, hepatic necrosis, and sudden fatalities. From these severe outbreaks, we discovered several previously unknown group A rotavirus (RVA) lineages of genotype G18P[17]‐I4‐R4‐C4‐M4‐A4‐T4‐N4‐E19‐H4, which were closely related but not identical to an RVA variant identified in cases of fatal hepatic necrosis in Australian pigeon lofts in 2016. Retrospective analysis demonstrated that the predecessors of the highly virulent variants have circulated in Europe since at least 2010. Our data indicate that reassortment and intercontinental spread has led to the emergence of novel RVA variants, which may constitute a major threat to animal welfare and health of domestic pigeon populations worldwide.

Cases of vomiting and diarrhoea were reported in racing pigeons in Western Australia in May, 2016. Morbidity and mortality rates were high. Similar clinical disease was seen in Victoria in December and by early 2017 had been reported in all states except the Northern Territory, in different classes of domestic pigeon–racing, fancy and meat bird–and in a flock of feral pigeons. Autopsy findings were frequently unremarkable; histological examination demonstrated significant hepatic necrosis as the major and consistent lesion, often with minimal inflammatory infiltration. Negative contrast tissue suspension and thin section transmission electron microscopy of liver demonstrated virus particles consistent with a member of the Reoviridae. Inoculation of trypsin-treated Vero, MDBK and MA-104 cell lines resulted in cytopathic changes at two days after infection. Next generation sequencing was undertaken using fresh liver samples and a previously undescribed group A rotavirus (genotype G18P[17]) of avian origin was identified and the virus was isolated in several cell lines. A q-RT-PCR assay was developed and used to screen a wider range of samples, including recovered birds. Episodes of disease have continued to occur and to reoccur in previously recovered lofts, with variable virulence reported. This is the first report of a rotavirus associated with hepatic necrosis in any avian species.

Canids are definitive hosts of the apicomplexan parasite Neospora caninum, the leading cause of abortion in cattle worldwide. For horizontal transmission from canids to occur, oocysts of N. caninum must be shed by the definitive host into the environment of susceptible intermediate hosts such as cattle. The purpose of this study was to determine the prevalence of N. caninum in canids in Victoria, Australia’s leading dairy producing state. Neospora-like oocysts were observed in 8% (18/234) of faecal samples from wild dogs, domestic dogs and red foxes from Victoria, Australia. However, none tested positive for N. caninum DNA using a quantitative PCR. In a separate sample population, blood sera from 483 domestic dogs were tested for anti-N. caninum antibodies using competitive ELISA. A subset of cELISA samples were re-tested using indirect fluorescence antibody test (IFAT). A seroprevalence of 29.8% (144/483; 95% CI: 11.7–47.8%) was calculated when using cELISA; whereas it was 32.9% (27/80; 95% CI: 15.8–51.8%) using IFAT. Potential risk factors were evaluated using univariable analyses and then assessed in separate multivariable models. Using ‘aged’ dogs as a reference, the seroprevalence of ‘adolescent’ and ‘adult’ dogs was 88% (P = 0.05) and 91% (P = 0.08), respectively, indicating seroprevalence increases with age. There was a 19% higher likelihood of infection in rural locations (P = 0.10) relative to urban areas. Jack Russell Terriers had a 22% higher risk of a cELISA-positive result (P = 0.05) regardless of geographical location, age or sex. These results demonstrate that exposure to N. caninum in domestic dogs is widespread in Victoria, although faecal oocyst shedding is infrequent. Our results indicate increased N. caninum seroprevalance status in dogs over the past two decades. The results imply that dogs get either exposed to the infected meat more frequently or that vertical dam to foetus transmission is more frequent than previously thought. Our study calls for re-evaluation of historical N. caninum seroprevalance studies, because the attitude to dog diet changes.