First Description of Nodular Onchocercosis (Onchocerca jakutensis) in Free-ranging Italian Red Deer (Cervus elaphus)

Onchocercosis is a vector-transmitted parasitic disease involving wild and domestic ungulates, humans, and dogs. Red deer (Cervus elaphus) host numerous Onchocerca spp. which have precise anatomic sites in the host and two species, Onchocerca flexuosa Wedl, 1856 and Onchocerca jakutensis Gubanow, 1964, are found inside subcutaneous nodules. Between September and November 2007, subcutaneous nodules were observed on both thighs in shot red deer of a Tuscany population. We observed cystic structures, surrounded by a fibrous capsule, containing nematodes. Filamentous worms were male and female; microfilariae were also described. Although morphologically we could not distinguish between O. flexuosa and O. jakutensis, genetic studies implicated O. jakutensis. This is the first report of this parasite in Italy.