Human Brucellosis - New Public Health Problem in Bulgaria

The aim of this study was to describe trends over time of human brucellosis (HB) based on national surveillance data from 1992 to 2016 in Bulgaria and to assess the factors of its re-emergence after 50 years elimination. Retrospective analytical study was applied and performed descriptive, spatial and time series analyses using national aggregated data for HB incidence from National Center of Infectious and Parasitic Diseases (NCIPD)-Sofia. During the 25-year period, 190 confirmed cases were reported, resulting in annual incidence of 0.10 cases per 100,000 populations. Dynamic model of the epidemic process and risk factor were analyzed. The fitted Autoregressive integrated moving average (ARIMA) model of HB incidence also was selected. There were differentiated two cycles of infection spreading out lasting 12-13 years with two epidemic waves (1996 and 2002). Greater incidence of HB was recorded during the peaks of epidemic waves in the second epidemic cycle – 0.52-0.76/100,000 population. Re-emergence of brucellosis in Bulgaria started from areas bordering endemic countries and gradually extended inland. The geographic location of Bulgaria as external border of European Union (EU) and transit crossroad among Asia, Africa and Europe increases the risk of HB re-emergence to the country. Involvement of all responsible institutions for public healthcare is required.