Herd-level seroprevalence, molecular prevalence, and trends of Coxiella burnetii (Q fever) in cattle worldwide: A systematic review and meta-analysis.

BACKGROUND AND AIM: Cattle are the reservoir host of Coxiella burnetii, a causative agent of Q fever. Pooling herd-level prevalence data from individual studies would help determine the global prevalence of C. burnetii in cattle herds. This study aimed to estimate the global herd-level seroprevalence and molecular prevalence of C. burnetii in cattle, explore sources of heterogeneity, and determine trends and cumulative evidence of the pooled prevalence over time.

MATERIALS AND

METHODS

Relevant studies were retrieved from PubMed, Scopus, and Web of Science and then screened for possible inclusion. A random-effects model was used for all meta-analyses. Subgroup meta-analysis and meta-regression were used to explore some sources of heterogeneity associated with the pooled prevalence and to determine the trends of C. burnetii in cattle herds over the study years (1961-2020). A cumulative meta-analysis was used to determine the cumulative evidence of the pooled prevalence over the publication years.

RESULTS

Of the 1541 citations, 86 studies with 38,057 cattle herds from 42 countries on six continents were included in the meta-analysis. The global herd-level seroprevalence of C. burnetii in cattle was estimated to be 44.4% (95% confidence interval [CI], 37.9%-51.1%), with high heterogeneity among the included studies. The herd-level seroprevalence was significantly higher in dairy than in beef cattle herds (49.0% [95% CI: 41.9%-56.2%] vs. 14.5% [95% CI: 5.8%-32.1%], respectively). The global herd-level molecular prevalence of C. burnetii in cattle was estimated to be 32.3% (95% CI: 25.3%-40.01%), with high heterogeneity among the included studies. Herd-level molecular prevalence was significantly different among continents. The herd-level molecular prevalence ranged from 12.8% (95% CI: 7.1%-21.9%) in Asia to 70.0% (95% CI: 36.3%-90.5%) in North America. Regarding trends, the herd-level seroprevalence of C. burnetii in cattle did not change significantlyover the study years.

CONCLUSION

The global herd-level seroprevalence and herd-level molecular prevalence of C. burnetii in cattle were high, estimated at 44% and 32%, respectively. The herd-level seroprevalence trend did not significantly change over time. This result indicates that cattle remain a major reservoir host for C. burnetii and pose a potential risk to human health.