Serological evidence of exposure to Coxiella burnetii in sheep and goats in central Portugal

The recent outbreak of Q fever in The Netherlands warned European health authorities of the need of studying Coxiella burnetii. In Portugal, little is known about C burnetii infection in animals. A cross-sectional study was designed to investigate the exposure to C. burnetii in sheep and goats in the Central region of Portugal, estimating the herd and individual prevalence. A serosurvey was conducted in a two levels random sampling of 89 herds and 460 animals. Individual blood samples were collected from animals older than 6 months, and specific antibodies anti-C. burnetii were detected by ELISA testing. Results showed a global herd prevalence of 32.6% (95% CI: 23.1-42.1%). Herd prevalence was higher in mixed herds (38.5%; 95% CI: 12-65%) and in sheep herds (37.5%; 95% Cl: 21-54%) than in goat herds (28.8%; 95% CI: 17-41%). Global individual prevalence was estimated at 9.6% (95% CI: 6.9-12.2%), and it was higher in goats (10.4%; 95% CI: 7.8-13%) than in sheep (8.6%; 95% CI: 5.8-11.4%). Sample positive percentages (S/P) ranged from 41.5% to 185.9%. S/P percent higher than 100 was found in 18.2% (8/44) of sera from distinct herds. Positive results were significantly associated with goats, older animals and larger herds. These results revealed the presence of C burnetii in small ruminants evidencing their potential role in the infection cycle. (C) 2013 Elsevier B.V. All rights reserved.