Focal myositis associated with Leishmania spp. infection in a dog – diagnostic approach

Abstract

Canine visceral leishmaniasis is a systemic, zoonotic disease widely spread in several countries. The disease is caused by Leishmania spp., and the dog is the main reservoir of this parasite. Clinical signs in the muscle skeletal system consist of muscle atrophy, weakness, lameness, abnormal locomotion, osteitis, polyarthritis, heat and swelling of the joints, enlarged local lymph nodes and pain. In this note, a case of canine myositis of the lumbar region associated with Leishmania spp. infection is reported. Clinical signs included weakness, fever, mild dehydration, enlarged mandibular, pre-scapular and popliteal lymph nodes and a large palpable soft mass in the lumbar region, semi-adhered and not painful. Serologic diagnosis resulted reagent by indirect immunofluorescence reaction method. Findings of ultrasonography of the lower back are described, revealing the misalignment of muscle fibers, interspersed with anechoic areas compatible with edema. Local fine needle aspiration cytology was crucial for a definitive diagnosis, revealing amastigote forms. In endemic areas of leishmaniasis, clinicians should consider this disease as a differential diagnosis in the presence of musculoskeletal injuries with no apparent cause.