Demodicosis in a Kunekune pig and molecular characterisation of porcine demodectic mites involved: a case report.

BACKGROUND: In January 2021, a female 1-year-old Kunekune was presented at the University Clinic for Swine with severe reduction of the field of vision resulting in prolonged reaction time when targeting barriers, due to moderate to severe thickening of the skin around both orbits also affecting the eyelids. METHODS: Clinical examination revealed skin hyperplasia, nodular enlargement of the skin pores of the axillar and inguinal region. Ophthalmologists decided to remove parts of the thickened periocular skin, followed by histopathological examination. RESULTS: Once large amounts of demodectic mites were detected by histopathology, demodicosis could be diagnosed and treatment of the pig was started using sarolaner. Morphological and molecular analyses were performed. Histopathological and parasitological exams led to the aetiological diagnosis of demodicosis in the affected Kunekune pig. Severe skin lesions were revealed to be the consequence of an infestation with Demodex sp. Morphological analyses confirmed the involvement of D. phylloides. Molecular characterization indicated a Demodex species closely related to mites documented in wild boar - most probably D. phylloides for which no explicit sequences are available in GenBank yet. Treatment with sarolaner (2.6 mg/kg) resulted in a substantial regression of skin lesions, already detectable 1 month after first treatment. CONCLUSIONS: Demodicosis is a very rare disease in pigs that is most probably related to an impaired immune response to the mites. Demodectic mange should be included in the list of differential diagnoses in cases of periocular alterations of the skin of pigs.

Immunohistochemical staining of immunoglobulin G in healthy equine, canine, and feline corneas.

OBJECTIVE: Establishing an immunohistochemical approach for semi-quantitative assessment of the presence of immunoglobulin G (IgG) in equine, canine, and feline corneas. PROCEDURES: Healthy corneas of horses, dogs, and cats, euthanized because of a fatal disease or an unrecoverable trauma unrelated to and without a history of ophthalmic disease were formalin-fixed, paraffin-embedded, and determined to be pathomorphologically healthy by light microscopy. Automated immunohistochemistry was performed using primary antibodies against IgG, biotin-conjugated secondary antibodies, and streptavidin-peroxidase, as well as diaminobenzidine for visualization. After counterstaining with hematoxylin, epithelium, stroma, Descemet´s membrane (DM), and endothelium were semi-quantitatively scored for the presence of IgG on a 4-grade scale (0 = no, 1 = faint, 2 = medium, 3 = strong staining) by light microscopy. RESULTS: Corneal specimens of 20 horses (40 eyes) with a median age of 15.5 years (range 2-31 years), 12 dogs (21 eyes) with a median age of 10.0 years (range 4-16), and 13 cats (24 eyes) with a median age of 10.0 years (range 2-18) were included in the study. Different sexes and breeds were represented. In all corneas (100%), significant medium signal intensity in the stroma was observed. Variable immunosignal was obtained in epithelium, DM, and endothelium. CONCLUSION: This method reproducibly allows for the detection of IgG in healthy equine, canine, and feline corneas, particularly stroma. Semi-quantitative results evidence medium presence of IgG in the corneal stroma. Further research is needed to evaluate IgG presence in diseased corneas.

Multiple Congenital Ocular Anomalies in a silver coat Missouri Fox Trotter stallion.

This is the first description of Multiple Congenital Ocular Anomalies (MCOA) in a silver coat Missouri Fox Trotter determined to be heterozygous for the Silver PMEL17 missense mutation associated with MCOA and a silver coat in other breeds. The stallion was treated for meningoencephalitis and bilateral uveitis of unknown origin. A complete ophthalmic examination and ocular ultrasonography were performed. As an incidental finding, the patient exhibited bilateral cystic lesions restricted to the temporal anterior uvea consistent with the Cyst phenotype and was genotyped heterozygous for the Silver mutation. Additionally, 4 other non-silver colored Missouri Fox Trotters were genotyped homozygous for the wild-type allele. Screening for PMEL17 mutation in Missouri Fox Trotters accompanied by ophthalmic phenotype characterization is recommended to determine the allelic frequency and facilitate informed breeding decisions since the silver coat color is particularly popular.