Seroprevalence of Coxiella burnetii infection (Q fever) in sheep farms located in Sicily (Southern Italy) and related risk factors

•First study on Q fever prevalence in Sicilian flocks: 18% in animals, 73% in farms.•Flock size and farm altitude were actual risk factors for the infection.•Sheep overcrowd plus dust and winds seem to increase C. burnetii spreading.•Useful information for increasing preventive measures (no vaccine available).