Surveillance of Q Fever in Dairy Cattle in Latvia: Molecular and Serological Findings and Association with Farm and Woodland Density.

Q fever, caused by the obligate intracellular bacterium Coxiella burnetii, is a widespread zoonotic disease and a notifiable condition in 25 European Union countries. Dairy cattle are important reservoirs, and infection can pose a risk to both animal and human health. The aim of this study was to assess the temporal and spatial prevalence of C. burnetii in dairy farms in Latvia. In the period of January 2016-December 2018, seroprevalence was estimated. Between January 2022 and September 2023, bulk tank milk and pooled milk samples were collected from 5.81% of Latvian dairy farms and analyzed for the presence of C. burnetii DNA using PCR. Overall, 15.46% of milk samples and 10.05% of farms tested positive. These two periods were retrospectively compared with previously published Q-fever prevalence data within Latvian territory. To identify potential risk factors, statistical analyses were performed, including correlation assessments with farm-level and environmental variables. These new surveillance data and historical temporal spatial changes in disease distribution confirm the continued circulation of C. burnetii in Latvian dairy herds and highlight environmental and herd-level associated factors that may influence its spread. Results indicated that C. burnetii prevalence was positively associated with a high cattle density and overflowing plains, while the presence of surrounding woodlands was negatively correlated, suggesting a potential natural barrier effect.