Background and objectives: The aim of this paper was determine the prevalence of antibodies against Francisella tularensis in the representative sample of people from Castilla-León (Spain) before epidemic outbreak of end 1997.
Subjects and method: We obtain 4,825 sera (between april-1996 and april-1997) of people from Castilla-León. All sera were tested by a microagglutination technique to detect antibodies against Francisella tularensis. The positive sera were tested to determine cross-reaction with Brucella, Yersinia enterocolitica and Proteus in the tube agglutination tests.
Results: We detected antibodies against Francisella tularensis in 9 (0,19%) of the 4,825 sera. Only one serum from the 9 seropositive was positive in the tube agglutination against Brucella. None of the 9 sera were positive against the remaining bacterial antigen tested.
Conclusions: In the people of Castilla-León before 1997 the prevalence of antibodies against Francisella tularensis was 0,19%.