Dirofilaria immitis and Dirofilaria repens co-infection in a microfilaremic dog from Negotin, Eastern Serbia: Unusual localization of adult Dirofilaia repens in an abdominal hernia sac.

Cardiopulmonary and subcutaneous dirofilariosis, caused by the nematodes Dirofilaria immitis and Dirofilaria repens, are vector-borne diseases of growing concern in both veterinary and human medicine. While typically found in predilection sites, atypical localizations have been documented for both species. The first case of adult D. repens found in a dog's abdominal hernia sac in Eastern Serbia is reported in this study. A 7-year-old dog was brought to a veterinary clinic in Negotin, Serbia with lateral abdominal swelling. During hernia repair surgery, three filiform nematodes were discovered on the peritoneal serosa of the hernial sac, later identified as D. repens. Modified Knott's test reveals the presence of both D. immitis/D. repens microfilariae. After surgical procedure and recovery, the dog was treated with monthly combination of imidacloprid and moxidectin (Advocate, Bayer AG), along with one-month course of doxycycline. This case highlights the need for awareness of zoonotic D. repens atypical presentations in endemic regions.