Two outbreaks of myxomatosis in domestic rabbits ( <i>Oryctolagus cuniculus</i> ) in Minas Gerais, Brazil

Abstract Myxomatosis is a highly contagious viral disease caused by the Myxoma virus, affecting domestic and wild rabbits and resulting in severe skin lesions and high mortality. This study reports the first outbreaks of myxomatosis in domestic rabbits in Minas Gerais, Brazil, detailing clinical, pathological, epidemiological and molecular aspects. Two unrelated outbreaks occurred, with morbidity rates of 17.2% (15/87) in a research facility and 92.3% (12/13) on a small breeding farm. Clinically, affected animals exhibited lethargy, crusted and nodular skin lesions, particularly on the snout and ears, along with marked eyelid and genital oedema and hyperaemia. Histopathology revealed epidermal hyperplasia, keratinocyte degeneration, intracytoplasmic inclusion bodies and extensive myxomatous matrix deposition in the dermis. Diagnosis was confirmed by polymerase chain reaction and sequencing, showing phylogenetic similarity between Brazilian and European virus strains. These findings highlight the importance of improved surveillance and biosecurity to control the disease.