TLR2 and infection: Experimental infections are needed to further confirm whether the TLR2 polymorphism in this species influences variation in susceptibility to infection with B. afzelii. The two aims of this study were to determine whether the TLR2 polymorphism in wild bank voles influences variation in the probability of infection with B. afzelii (hereafter referred to as host susceptibility) and variation in B. afzelii spirochete abundance in host tissues (hereafter referred to as host spirochete load).