The sample size for detecting C. burnetii antibodies within each herd was also calculated with WinEpiscope2.0,
given a within-herd prevalence of 25% (based onpreliminary studies),
a herd size of 1000 (greater than the largest herd in Ecuador) and a significance level of95%,
yielding a minimum sample size of 11 animals perherd. When the number of animals of the farm waslower than 12, all animals older than 6 months were sampled