Retrospective evaluation of pre-surgical electroretinography results in a mixed-breed canine population presented for cataract removal surgery.

OBJECTIVE: Electroretinography (ERG) is used prior to cataract removal surgery to assess retinal function. We aimed to replicate and improve upon previous studies by performing a full ECVO protocol and by examining the retina post-surgery in all patients. ANIMALS STUDIED: One hundred twenty-seven eyes from 67 dogs were included in the study. PROCEDURES: A full ECVO protocol electroretinography, which includes extensive rod and cone analysis, was performed on all dogs presenting for cataract surgery. RESULTS: Our main findings were that amplitudes, but not implicit times of rod responses decreased with advanced cataracts. Amplitudes of the single flash rod and rod flicker responses were significantly lower in eyes with mature cataracts, and the former also decreased in hypermature cataracts. Cone flicker amplitude responses were also significantly lower in eyes with mature and hypermature cataracts. However, mixed single flash rod-cone and cone responses, with the exception of the mixed rod-cone a-wave amplitude in eyes with hypermature cataracts, were unaffected by cataract stage. The b-wave amplitude of the scotopic, mixed rod-cone, and photopic cone responses were affected by age and decreased by an average of 2.9, 7.5, and 1.5 µV/year, retrospectively (p < 0.01). CONCLUSIONS: Lower ERG amplitudes in canine cataract patients may result from aging or the presence of advanced cataracts and may not indicate the presence of retinal disease.

Canine idiopathic orbital inflammation: A case series of four affected dogs (five orbits).

PURPOSE: In humans, idiopathic orbital inflammation (IOI) is a diagnosis attributed to benign, inflammatory orbital conditions without identifiable local or systemic cause. We describe the clinical signs, imaging and histopathological findings, management and outcome of four dogs diagnosed with IOI. METHODS: Multicentric retrospective study. RESULTS: A total of four dogs (five orbits) of three different breeds (three cases were English Springer Spaniels [ESS] or ESS-cross) and ages ranging from 3 to 12 years were included. Initial presenting signs were unilateral and included exophthalmos, enophthalmos, globe deviation, thickening and protrusion of the third eyelid and conjunctival hyperemia. Computed tomography and magnetic resonance imaging identified heterogeneous space-occupying, contrast-enhancing orbital lesions in all cases. Sparing of the retrobulbar space was detected in four of five orbits. Histopathology revealed mixed inflammatory infiltrates of lymphocytes, plasma cells, and histiocytes. Immunohistochemistry was performed in two cases highlighting the presence of histiocytes and lymphocytes, predominantly T cells. Resolution of clinical signs was achieved in two cases managed with oral immunosuppressant medication (corticosteroids alone or combined with cyclosporine or azathioprine), one went into spontaneous remission, one resolved with topical corticosteroids, and one underwent exenteration. Recurrence occurred in two cases within 15 months of initial diagnosis and required further immunosuppressant medication. One case developed signs in the contralateral orbit within 8 months of presentation. CONCLUSIONS: IOI is an uncommon condition in dogs. Its diagnosis relies on the combination of advanced imaging and histology. As in humans, it appears that spontaneous remission and recurrence may occur requiring long-term immunosuppressant medication.

Comparison of the prevalence of Domestic Cat Hepadnavirus in a population of cats with uveitis and in a healthy blood donor cat population in the United Kingdom.

OBJECTIVE: Domestic Cat Hepadnavirus (DCH) is a novel virus recently identified in the domestic cat. Currently, little is known regarding its clinical significance. The hepadnaviridae family includes the Hepatitis B Virus (HBV). Co-infection of HBV and Hepatitis C in humans increases the risk of uveitis. We aimed to determine whether DCH is present in the United Kingdom (UK) and whether DCH warrants investigation as a potential cause of uveitis in cats. PROCEDURES: Clinical records from the Royal Veterinary College (RVC) and the Animal Health Trust (AHT) were reviewed for feline cases diagnosed with endogenous uveitis. A healthy control group was identified from cats presented to the RVC as blood donors. DNA was extracted from stored blood samples using commercially available kits. Polymerase chain reaction assays were performed to confirm the presence of feline DNA and to detect the presence of DCH DNA using previously described protocols. RESULTS: Blood samples were available from 65 cats with endogenous uveitis and 43 healthy control cats. Two blood samples from cats with endogenous uveitis tested positive for the presence of DCH DNA. DCH DNA was not detected in the control group. There was no statistically significant difference between the prevalence of DCH between the groups. CONCLUSIONS: Domestic Cat Hepadnavirus is present in the UK. This study failed to demonstrate a conclusive link between DCH and uveitis in cats, although further studies to investigate an association with other feline diseases are warranted.

A multicenter retrospective study into endogenous causes of uveitis in cats in the United Kingdom: Ninety two cases.

PURPOSE: The purpose of this study was to investigate the most common causes of endogenous feline uveitis in a UK referral population and to investigate associations based on signalment. METHODS: Retrospective multicenter cross-sectional study from 2010 to 2019 including cats presented to the Animal Health Trust and the Royal Veterinary College with clinical signs consistent with uveitis. Cats were included in analyzes if they had a full physical examination including an ophthalmic examination, complete blood count, serum biochemistry, and infectious disease testing for at least two diseases unless the diagnosis was found on clinical examination (eg, neoplasia). RESULTS: A total of 92 cats were included in the study. The majority of cats presenting with uveitis were male (66.3%). The most common causes of endogenous uveitis were idiopathic uveitis (42/92 45.7%), feline infectious peritonitis (FIP) 15/92 16.3%), and lymphoma (10/92 10.9%). Fisher's exact test showed differences in breed across diagnosis groups (p = .002) with purebred cats being overrepresented in the lymphoma and FIP groups. Kruskal-Wallis test showed differences in median age across diagnosis groups (p < .001) with cats in the FIP group having the youngest age (median 1.4 years, interquartile range (IQR) 0.4-1.8 years) and cats in the neoplasia (primary or paraneoplastic) group having the oldest age (median 12.8 IQR 10.8-13.8). Idiopathic uveitis was unilateral in 56.1% of cases, and infectious causes were unilateral in 47.8% of cases. CONCLUSIONS: The most common cause of endogenous uveitis in a population of cats in the UK was idiopathic uveitis, followed by FIP and lymphoma.

Feline tuberculosis caused by Mycobacterium bovis infection of domestic UK cats associated with feeding a commercial raw food diet.

Mycobacterium (M.) bovis can infect cats and is a demonstrated zoonosis. We describe an outbreak of M. bovis in pet cats across England and Scotland associated with feeding a commercial raw food diet. Forty-seven cats presented with (pyo)granulomatous lesions, lymphadenopathy, pulmonary and/or alimentary disease over a one-year period where M. bovis infection was suspected or definitively diagnosed, and the cats all consumed the same specific brand of commercial raw venison pet food. Infection with M. bovis genotype 10:a was confirmed by culture and DNA typing of isolates in a small number of cases (n = 5); PCR was used in combination with or as an alternative to culture (n = 12) and/or infection with a Mycobacterium tuberculosis complex group organism was strongly suggested by positive responses to an interferon-gamma release assay (IGRA; n = 34). Asymptomatic at-risk cats were screened by IGRA, identifying a further 83 infected cats. The five culture-positive cases were distributed across areas of England and Scotland at low risk of endemic bovine tuberculosis. Investigations revealed affected cats were mainly indoor-only, and had been fed the same commercial raw food as at least part of their diet. This diet was recalled by the manufacturer due to failure of statutory meat inspection of the component venison. As far as possible, other sources of infection were explored and excluded, including wildlife contact, access to raw milk and living with people with active M. bovis infection. Four owners and one veterinary surgeon were found to have high likelihood of latent tuberculosis infection. One owner required treatment. Although it was not possible to conclusively demonstrate a zoonotic origin for these infections, neither was it possible to eliminate the possibility. Our results provide compelling evidence that the commercial raw diet of these cats was the likely route of M. bovis infection in this outbreak of cases.

A retrospective evaluation of systemic and/or topical pilocarpine treatment for canine neurogenic dry eye: 11 cases.

OBJECTIVE: To assess the response to topical and/or systemic pilocarpine in dogs with neurogenic dry eye. METHOD: Medical records of dogs diagnosed with dry eye between 2015 and 2018 were reviewed. Cases were excluded if STT values were decreased bilaterally, if dogs were lost to follow-up, or if surgical measures (parotid duct transposition) were undertaken within thirty days of presentation. Dogs were on treatment with topical pilocarpine (0.1%, every 6 hours) and/or oral pilocarpine (starting dose 2%, one drop per 10 kg every twelve hours). RESULTS: Eleven cases were included in the study, seven females and four males with mean age of 10 years. Seven cases had xeromycteria, two cases had facial nerve paralysis, and one case had Horner's syndrome. Seven cases (63.6%) had successful outcome following pilocarpine treatment, return to normal STT (15-25mm/minute), in an average of 24 ± 5.1 days. Of these cases, five had both systemic and topical treatment, one had just topical treatment, and one had just systemic treatment. The average time to normal tear production on treatment with topical pilocarpine ± systemic was 23 days (range 9-48 days). The number of systemic drops until a positive response varied between individuals from 0.8drops/10kg to 7drops/10kg. CONCLUSION: Pilocarpine treatment (topical ± systemic) is an effective therapy for unilateral dry eye disease in cases suspected to be neurogenic in origin. Most cases responded within 30 days. Side effects included topical irritation to the ophthalmic solution and systemic effects from oral pilocarpine, such as diarrhea and regurgitation.