TLR4 and Lyme disease: In addition, we used our established laboratory models of Lyme borreliosis [4,23,24] to test whether stimulation or blocking of the tick Toll pathway affects the (i) acquisition of Borrelia spirochetes by I. ricinus nymphs immediately after feeding and one and two weeks after feeding on infected mice or (ii) transmission of spirochetes from Borrelia-infected nymphs to the naïve mouse.