Dermatitis caused by autochthonous Cercopithifilaria bainae from a dog in Florida, USA: clinical, histological and parasitological diagnosis and treatment

Abstract

Background: Cercopithifilaria bainae is a tick-vectored filarioid nematode associated with erythematous dermatitis in dogs. It has not been reported previously in the United States. Hypothesis/Objective: To describe clinical, histological and parasitological diagnosis and treatment of C. bainae in a dog. Animals: An 11-month-old golden retriever/standard poodle mixed breed dog from Florida (USA). Methods and materials: The dog had no travel history within or outside the United States, was presented with a one month history of annular erythematous plaques on the head and ulcers on the medial canthi. Lesions were unresponsive to antibiotic treatment. Results: Histopathological evaluation of skin biopsies revealed an eosinophilic to lymphohistiocytic perivascular dermatitis with multiple microgranulomas and rare 5–10 μm diameter microfilariae within microgranulomas. Microfilarial morphology was consistent with C. bainae. PCR and sequencing of 18S rRNA and mitochondrial cytochrome oxidase subunit I genes confirmed the nematodes as C. bainae. The dog was treated with a commercial spot-on containing imidacloprid and moxidectin, and clinical resolution occurred. Conclusions and clinical importance: To the best of the authors’ knowledge, this is the first report of C. bainae in a dog in the United States and the first description of dermatological lesions caused primarily by C. bainae.