Molecular characterization of Echinococcus granulosus Horse strain (G4) in Continental Ital

Echinococcus granulosus (Eg) shows a great intraspecific variation.. This variability led to the identification of 10 different genotypes and genetic variants of the parasite (G1–G10). In horses, cystic echinococcosis (CE) has a quite low diffusion and seems to be strictly correlated to species-specific infection with horse own subspecific variant of Eg, named, after biomolecular characterization, G4 or horse strain. In Italy, this strain was identified by molecular tools for the first time in 2006 in Sardinia. Aim of the present paper is to report the first identification of G4 strain in Continental Italy. Liver and lungs from 7,500 horses, slaughtered in the province of Reggio Emilia (Emilia-Romagna Region, Northern Italy) during the period from March 2006 to February 2007, were examined for CE. DNA was extracted from germinal layer and protoscoleces of a fertile cyst and PCR reactions were performed in order to strain typing DNA isolates. PCR products were then purified and sequenced in forward and reverse. Liver cysts were found in two horses. A horse harboured one calcified cyst; the other presented two fertile cysts and hydatid material obtained from one cyst (10 cm) was identified as G4 strain of Eg for ND1 and CO1 partial genes. The animal, a 10-year-old female, came from the province of Grosseto (Tuscany Region, Central Italy) and was permanently maintained on pasture together with sheep, cattle and other horses. This is the first molecular identification of the Eg horse strain or G4 in Continental Italy.