Screening of various foodstuffs for occurrence of Coxiella burnetii in Switzerland

The epidemiology of Q-fever in Switzerland is largely unknown. For this reason, a screening programme for the presence of Coxiella burnetii in bulk milk samples from cows, sheep and goats and in shell eggs produced in and imported into Switzerland was conducted. In total, 17 of 359 (4.7%) of analysed bovine milk samples from two randomly selected cheese dairies were tested positive for C. burnetii by nested PCR. Furthermore, the findings with samples from one dairy showed that the agent seemed to persist over time in the herds of cattle of certain farms. Although no extensive prevalence study was undertaken, our results indicate that C. burnetii appears to be quite frequent in cattle. As for 81 ovine and 39 caprine bulk milk samples, they were all tested negative for C. burnetii. Finally, 504 shell eggs were also found to be negative for C. burnetii with PCR testing. The results of the study are discussed under inclusion of epidemiological data for human and animal coxiellosis and the current Swiss legal regulations for the control of C. burnetii in cattle.