Clinical presentation of acute Q fever in Spain: seasonal and geographical differences

The aims of this study were to improve our understanding of the clinical forms of presentation of acute Q fever in Spain and to determine any possible relationships with geographical and seasonal factors.

This was a retrospective study of 183 cases of acute Q fever from three Spanish regions, Catalonia, Canary Islands, and La Rioja.

The main clinical form of presentation was hepatitis (49.2%), followed by isolate febrile syndrome (31.7%) and pneumonia (19.1%). The proportion of cases presenting as pneumonia was significantly higher in La Rioja (40.7%) than in Catalonia (18.3%) or the Canary Islands (12.9%) (p=0.001). In Catalonia and the Canary Islands, most cases (52.1% and 57.6%, respectively) were diagnosed between March and June, whereas in La Rioja, most cases (51.8%) occurred between November and February. Overall, the proportion of cases presenting as pneumonia was significantly higher in the period from November to February (32.6%) than in the periods March-June (16.0%) and July-October (13.0%) (p=0.01).

Our results suggest the existence of seasonal differences in the presentation of acute Q fever in Spain, with a higher proportion of pneumonic forms in the colder months. Furthermore, we confirmed the existence of geographical differences, with a higher proportion of pneumonic forms in the region of La Rioja, in the north of the country.