Spatial Distribution and Epidemiology of Echinococcus Granulosus Infection in Sheep and Goats Slaughtered in a Hyperendemic European Mediterranean Area

Background: Cystic echinococcosis (CE) is a parasitic zoonosis caused by the larval stage of Echinococcus granulosus, highly widespread in livestock, particularly sheep and goats. This study aimed to evaluate the spatial distribution of CE in sheep and goats slaughtered in a hyperendemic Mediterranean area.Methods: A survey was conducted in Basilicata region (southern Italy) from 2014 to 2019. A total of 1454 animals (1265 sheep and 189 goats) from 824 farms were examined for hydatid cysts detection by visual inspection, palpation and incision of target organs. All the CE cysts were counted and classified into five morphostructural types (unilocular, multisepted, calcified, caseous and hyperlaminated). The molecular analysis was performed on 50 cysts. For spatial analysis, kriging interpolation method was used to create risk maps, while the clustering was assessed by Moran’s I test.Results: CE prevalence of 72.2% (595/824) and 58.4% (849/1454) were observed at the farm and animal level, respectively, with higher values in sheep (62.9%) than goats (28.0%). The liver and lungs were the most frequently infected organs both in sheep and goats. Most of recovered cysts belonged to the calcified and multisepted morphotypes. All the isolates were identified as E. granulosus sensu stricto (genotypes G1-G3). Spatial distribution showed a moderate clustering of positive animals.Conclusions: The findings of this study can be used to better understand the eco-epidemiology of echinococcosis and to improve the CE surveillance and prevention programs in regions highly endemic for CE.