Autochthonous feline leprosy caused by Mycobacterium sp. strain Tarwin affecting a cat from the Central Coast of New South Wales

Case report: A 5-year-old Domestic Shorthair-cross was presented with a raised, alopecic skin nodule affecting the external surface of the right upper lip with an adjacent second smaller satellite lesion. Fine needle aspiration cytology revealed numerous intracellular and extracellular negatively stained bacilli. Histopathology confirmed granulomatous inflammation with multinucleate giant cell formation and abundant intracellular acid-fast bacilli, consistent with a mycobacterial aetiology. PCR testing of the fresh tissue from the satellite lesion and subsequent sequence analysis identified Mycobacterium sp. strain Tarwin. The skin lesion was surgically excised and clarithromycin 62.5?mg twice daily was administered to the cat for 25 days. Conclusion: There was no recurrence of the lesion at the time of writing, 16 months after the surgery. This is the second autochthonous case of feline leprosy caused by M. sp. strain Tarwin originating in New South Wales, Australia.