Dirofilariasis due to Dirofilaria repens in Italy, an emergent zoonosis: report of 60 new cases

Aims: Sixty new cases of human dirofilariasis due to Dirofilaria repens, oc curring in Italy between 1990 and 1999, are presented. This is the most ext ensive case study of this zoonosis reported worldwide by a single study gro up. The aim is to utilize this large experience to characterize the differe nt histopathological findings in the parasitic lesions in man. Methods and results: Diagnosis was performed on histological sections of th e nematode enclosed in the nodules excised at biopsy or surgery. The nemato de was located in the subcutaneous tissue (49 cases), the epididymis (two c ases), the spermatic cord (two cases), the lung (two cases), the breast (tw o cases), the omentum (two cases) and under the conjunctival tissue tone ca se). The majority of cases (46) were from Piedmont; the remainder were from Emilia-Romagna, Sardinia, Sicily, Tuscany, Apulia and Lombardy The histopa thological features of the lesions are described and the clinical and epide miological aspects of the zoonosis are discussed, The prevalence in Italy i n general and in the area of Piedmont in particular comprising the province s of Alessandria, Asti, Novara and Vercelli, which is one of the most sever ely affected areas of the world, is emphasized. The evident increase in the number of cases in the last few years is a clear indication that it is an emergent zoonosis. Conclusions: We recommend that each and every case observed be recorded, to enable the true extent of human dirofilariasis in Italy to be assessed, an d that a reference centre be set up in the area to collate the data. The im portance of the histopathologist's role in the diagnosis is stressed.