This survey showed a noteworthy distribution of helminths on sheep farms of the Basilicata region. The most prevalent helminths were GI strongyles, detected on most of the farms (91.8 %), and comprised the genera Haemonchus (76.9 %), Trichostrongylus (91.8 %), Teladorsagia (88.8 %), Cooperia (77.6 %), and Oesophagostomum (72.5 %). Lungworms were also widely distributed (50 %) and Muellerius was most commonly detected genus (37.8 %). These findings are consistent with similar studies performed in other Apenninic areas of southern Italy (Cringoli et al. 2002; Biggeri et al. 2007). The prevalence values for Trichuris (39.8 %), Nematodirus (24.5 %), Strongyloides (4.1 %), and Skrjabinema (2 %) are also consistent with those recently reported on sheep farms in other Italian regions (Bosco et al. 2011 ). D. dendriticum was the most prevalent liver fluke (61.2 %), whereas F. hepatica was reported on only 1 % of the farms. Paramphistomes (C. daubneyi) were reported on 10.2 % of farms.

Spatial analysis detected an interesting cluster distribution of D. dendriticum and C. daubneyi in the study area, likely due to soil and environmental characteristics on the biology of the intermediate hosts. Further studies are needed to clarify this finding.

In conclusion, considering that the health status of livestock is fundamental for the productive and reproductive performances of these animals, the economic impact of this parasitological situation is likely very significant, although not quantified in this study (Cringoli et al. 2004, 2007, 2008). Local knowledge about the presence and distribution of parasitic infections in sheep is a basic requirement to better plan and implement appropriate control protocols and targeted strategies.