Spatial and temporal trends of Mediterranean spotted fever in Spain, 2005-2015

Background: Mediterranean spotted fever (MSF) is a zoonotic disease caused by Rickettsia conorii and transmitted by Rhipicephalus sanguineus sensu lato. The aim of this study is to understand the epidemiology and trends regarding the disease in Spain, based on notifications to the Spanish National Epidemiology Surveillance Network (RENAVE) and the National Hospital Discharge Database (CMBD) between 2005 and 2015. Methods: We carried out a retrospective cross-sectional study of the cases and the outbreaks reported to the RENAVE and of those found in the CMBD between January 1st, 2005 and December 31st, 2015. We studied the characteristics of the cases and analyzed their spatio-temporal distribution. Results: 1603 cases notified to the RENAVE and 1789 cases registered in the CMBD were analyzed. The most affected group were men between 45 and 64. There were 8 MSF outbreaks during the study period. RENAVE registered lower rates until 2012, when it was decided that MSF in Spain would become a notifiable disease. Across the temporal series we saw that there was seasonality with an increase in cases in summer, and an overall upward trend according to the RENAVE data and descending according to the CMBD. The geographic distribution was heterogeneous throughout the territory, with maximum rates in La Rioja at 1.87 cases and 2.01 cases per 100,000 inhabitants according to the RENAVE and the CMBD, respectively. Conclusions: It is of great importance to continue monitoring the disease since it appears to be endemic throughout Spain. There is a need for a common strategy on monitoring and reporting, which would facilitate a more accurate picture on the MSF epidemiological scenario. Entomological information will be of added value.