Human subcutaneous dirofilariasis. 1. Two new cases in Venice. Identification of the causal agent as Dirofilaria repens Raillet and Henry, 1911.

Two human cases of subcutaneous dirofilariasis are described in a 41 year-old woman and in a 14 year-old boy living in Venice Lido. In the first case, the development of a nodule at the left forearm had been preceded by generalized symptoms such as pruriginous urticarioid patches in various regions of the body, transitory swellings and 8% eosinophilia. From the nodule, an adult female of Dirofilaria repens was recovered with embryos visible in the uterus. In the second case, the parasite was localized in the scrotum, where it had caused an extensive oedema with the formation of a nodule having the size of a nut. An immature female specimen of D. repens was found. In both cases, the serological tests (Indirect Haemoagglutination and Bentonite Flocculation) gave significant titres specific for filariasis (1:256 and 1:20 in the first case, 1:128 and 1:5 in the second, respectively). A parasitological survey of blood samples from 145 stray dogs captured in the territory of the Venice municipality revealed the presence of D. repens in 8.3% of cases, D. immitis in 4.8% and Dipetalonema reconditum in 0.7%. This is the first time that the aetiological agent of human subcutaneous dirofilariasis was identified as D. repens in Italy.