Ectopic migration of Dirofilaria immitis in a Eurasian otter (Lutra lutra) in Korea

An 8-year-old female Eurasian otter (Lutra lutra) reared in a wetland center, died 2 h after sudden onset of astasia and dyspnea despite medical treatment. Gross examination of internal organs revealed 10 adult filarioid nematodes in the right ventricle of the heart and three between the left and right cerebral hemispheres. All nematodes were identified as Dirofilaria immitis by direct microscopy and polymerase chain reaction assay. Histopathological observation revealed multifocal hemorrhage in the cerebral subarachnoid space and focal necrosis with hemorrhage in the cerebellar parenchyma. Although rare, veterinarians should consider cerebral dirofilariasis as a differential diagnosis in unexplained neurological cases.