The seroprevalence of Coxiella burnetii in Erzincan, Turkey: Identification of the risk factors and their relationship with geographical features

Background & objectives: Coxiella burnetii (C. burnetii) bacterium, the causative agent of Q fever has regained importance due to the increasing cases of infections and outbreaks. A cross-sectional descriptive study was conducted to investigate the seroprevalence of C. burnetii in human populations of Erzincan province located in the eastern Turkey, identify the risk factors, and to explore the relationship between geographical features. Methods: A total of 368 people residing in the rural (306) and urban (62) areas of the province were included in the study. Serum samples were analyzed for the presence of C. burnetii phase II IgG antibody using ELISA (Virion/Serion, Wurzburg, Germany). Spatial analyses were performed to evaluate correlations between seroprevalence and geographical features. Results: The overall seroprevalence of C. burnetii was found to be 8.7% (32/368). In rural residents it was 8.5% (26/306), while in urban population it was 9.7% (6/62). Cattle breeding and contact with animal afterbirth waste were found to be major risk factors, and were significantly correlated with seropositive cases (p < 0.05). The seropositive cases were only observed in the areas between 1067 and 1923 masl. Of the total seropositive cases, 65.6% were within 1000 m and 87.5% within 4000 m of rivers and their main tributaries. Around 59.4% cases were observed in areas with a slope of 0 to 5 degrees. Interpretation & conclusion: The results of the study showed that C. burnetii seroprevalence was higher than expected, and significantly differs according to geographical features of a region. Significant risk factors include raising cattle and exposure to infected animals or their birth products/secretions. It is also more frequent in areas with higher number of rivers and streams, higher altitude and lower slope.