Prevalence of Coxiella burnetii antibodies in Portuguese dairy cattle herds.

Q fever is an important zoonotic disease which has been recently diagnosed, mainly in sheep and goats, in Portugal. The aim of the present study was to determine the prevalence of bovine Coxiella burnetii antibodies in dairy farms from the northwest of Portugal. Bulk tank milk samples were randomly obtained, on November 2013, from 90 dairy farms and assayed using an ELISA kit. The apparent prevalence was 61.1% (95% C.I. from 50.8 to 70.5%). The proportion of negative and intermediate (inconclusive) herds was 34.5% (25.5 to 44.7%) and 4.4% (1.7 to 10.9%), respectively. In conclusion, a high level of exposure to Coxiella burnetii was observed in Portuguese dairy cattle herds, highlighting the needs to better understand the epidemiology of Q fever in Portugal by the implementation of a monitoring program based on harmonized serologic and molecular methodologies and elucidation of the infection status of the herds.