Tracking the footsteps of Francisella tularensis: Bacteriological and serological monitoring in epidemic areas in Ankara

The study aimed to detect Francisella tularensis (F. tularensis) in water samples and to investigate the seroreactivity of sheep to tularemia in endemic areas where human tularemia cases have been reported in Ankara, Turkey. For the isolation of F. tularensis, 50 water samples were collected from rural areas of 5 regions of Ankara (Turkey) and selectively cultured on Francis medium supplemented with 8–9 % sheep blood and antibiotics (100 IU/ml penicillin G, 100 mg/L cycloheximide, 80,000 U/L polymixin B). No F. tularensis isolate was cultivated from the water samples. To determine the seroreactivity of sheep to tularemia, 1006 sheep blood samples were collected from the regions, where human tularemia is endemic. A microagglutination test (MAT) identified significant antibody titers, ranging from 1/20–1/640 in 181 (17.99 %) of the investigated sheep sera. Further investigation is required in order to evaluate and confirm a possible epidemiologic relationship between human outbreaks and probable role of sheep or other sources.