Aberrant peritoneal localization of Dirofilaria repens in a dog

Subcutaneous dirofilariosis is a widely spread vector-borne zoonotic disease caused by Dirofilaria repens. In the last years, a rise of human and animal cases of infection by D. repens has been reported in different European countries. The disease may be subclinical or characterized by different skin conditions. This report describes an unusual ectopic localization of D. repens in a naturally infected dog. The six-year old Pit Bull mixed breed dog presented dysorexia, exercise intolerance, orchialgia and moderate abdominal effusion. The abdominal ultrasound examination revealed multiple linear tubular structures with writhing and undulating movements within the peritoneal effusion. The microscopic examination of the peritoneal effusion revealed many larvae microscopically and molecularly identified as D. repens. This is the first case of peritoneal localization of D. repens in a dog. Epidemiological implications are discussed.