Clinically Mild Tularemia Associated with Tick-Borne Francisella tularensis
G. P. Schmid, A. N. Kornblatt*, C. A. Connors†, C. Patton, J. Camey‡, J. Hobbs and A. F.
Kaufmann
The Journal of Infectious Diseases Volume 148, Issue 1Pp. 63-67
This article mentions about the possibility of a mild infection. Possibly you are carrying the antibodies to an earlier infection. Only a raising titre of antibodies would be diagnostic of present infection.