First case of canine proliferative pleural, peritoneal, and scrotal cestodosis in algeria caused by mesocestoides sp. metacestodes: anatomical and histopathological findings.

Canine peritoneal larval cestodosis (CPLC) is an uncommon and underdiagnosed infection, with limited knowledge regarding its diagnosis, treatment, and the biological characteristics of Mesocestoides spp. A case of disseminated proliferative mesocestoidosis in a two-year-old intact male Spanish Galgo dog is described. The dog presented with a 10-day history of severe respiratory distress, lethargy, inappetence, progressive weight loss, abdominal distension with marked pain on palpation, and paraphimosis. Supportive treatment attempts were unsuccessful, and given the severity of the clinical signs and the animal’s poor condition, euthanasia was required. At necropsy, numerous parasitic structures were observed, mainly free in the thoracic cavity and forming cysts on the surfaces of organs such as the lungs, the liver, and the kidneys. These cysts were especially abundant in the mediastinal lymph nodes. Histopathological examination of affected organs revealed cystic formations containing one or more larvae, surrounded by a thin fibrous capsule. This case provides valuable insights into the occurrence and pathological features of Mesocestoides sp. infection in dogs from Algeria, underlining the need for greater clinical awareness of this parasitic disease.