An outbreak of cutaneous leishmaniasis in Modena province (Northern Italy): report of 35 cases

Canine Leishmaniasis is a disease endemic in many parts of Europe, carried by insects of phlebotomous species. Humans are occasional hosts of the parasites. Cases of human leishmaniasis have been registered in Italy, particularly in the southern and coastal regions. In the period 1997-2016, we collected a series of 35 patients affected by cutaneous leishmaniasis, uncovered by skin biopsy and histological examination, 21 of them found in last 3 years. The patients, 28 males and 7 female, aged between 19 and 91, resided in a restricted area of Northern Italy, and none, but two, had travelled abroad. Lesions presented clinically mostly as single nodule or plaque, often ulcerated, and involved predominantly head-neck and upper extremities. Histology showed a diffuse, granulomatous inflammation including numerous plasma cells. Variable numbers of amastigotes were visible, usually in the superficial part of the dermis, in all cases but two. In these two cases, highly suspicious by clinico-pathologic features, PCR analysis allowed to achieve the correct diagnosis. Our attention was then focused on the geographical residence of the patients, that turned out to be mostly in the piedmont area, whereas only one lived in the alluvial area corresponding to Padana plain. These data underline the diffusion of phlebotomus in northern areas of Italy, and particularly on the hills, characterized by a type of soil more favorable to vector survival; also, they indicate the adaptation of leishmania to hosts other than dogs, such as foxes and small rodents. Histology alone resulted sufficient to make diagnosis in most cases, but PCR analysis is recommended in those cases showing a suspicious background, in absence of amastigotes.