Geo-referencing livestock farms as tool for studying cystic echinococcosis epidemiology in cattle and water buffaloes from southern Italy

Cystic echinococcosis (CE), caused by the larval stages of the tapeworm Echinococcus granulosus, is known to be one of the most important parasitic infection in livestock worldwide and one of the most widespread zoonoses known. In the present study, we used a geographical information system (GIS) to study the spatial structure of livestock (cattle, water buffaloes and sheep) populations to gain a better understanding of the role of sheep as reservoir for the transmission of CE to cattle and water buffaloes. To this end, a survey on CE in cattle and water buffaloes from the Campania region of southern Italy was conducted and the geo-referenced results linked to the regional farm geo-referenced data within a GIS. The results showed a noteworthy prevalence of CE in cattle and water buffalo farms (overall prevalence = 18.6%). The elaboration of the data with a GIS approach showed a close proximity of the bovine and/or water buffalo CE positive farms with the ovine farms present in the study area, thus giving important information on the significance of sheep and free-ranging canids in the transmission cycles of CE in relation to cattle and water buffaloes. The significantly higher prevalence found in cattle as compared to water buffalo farms (20.0% versus 12.4%) supports the key role of sheep in the CE transmission; indeed, within the 5 km radius buffer zones constructed around the cattle farms positive for CE, a higher number of (potentially infected) sheep farms were found compared to those found within the buffer zones around the water buffalo farms. Furthermore, the average distances between the sheep and cattle farms falling in the same buffer zones were significantly lower than those between the sheep and water buffalo farms. We emphasize that the use of GIS is a novel approach to further our understanding of the epidemiology and control of CE and we encourage other groups to make use of it.