Introduction: Dirofilariasis is a zoonosis usually found in dogs and cats. It is rare in humans, who are dead-end hosts for the parasite.
Cases: We report 3 cases of subcutaneous dirofilariasis due to Dirofilaria repens, contracted in the south of France (Alpes-Maritimes and Corsica). In the first two cases, the dirofilariasis manifested as lymph node enlargement; in the third case, lung disease suggested a systemic diffusion of microfilariae.
Discussion: Dirofilaria repens dirofilariasis is due to the transmission of microfilariae by some mosquito bites (Aedes, Culex, Anopheles, Mansonia, Psorophora and Taeniorhynchus). Usually only one larva develops, producing an immature adult worm inside a node. Ultrasound examination may suggest the parasitic origin of the lesion. It is treated surgically, by excision, without chemotherapy. Very rarely, an adult worm may mature and produce systemic diffusion of microfilariae. The nodule in the third case contained a gravid adult female worm but we found no microfilariae. Dirofilariosis can present problems in diagnosis and treatment. It must be considered in patients with an isolated nodule.