Effect of salivary gland extract from Ixodes ricinus ticks on the proliferation of Borrelia burgdorferi sensu stricto in vivo

Saliva-activated transmission (SAT) of Borrelia burgdorferi sensu stricto was demonstrated using real-time PCR and salivary gland extract (SGE) from partially fed Ixodes ricinus tick's. C3H/HeN mice were injected intradermally with 1.5 x 10(3) spirochetes mixed with 40 mu g of SGE per mouse. The control group was inoculated with the same dose of spirochetes without SGE. The accelerating effect of SGE on spirochete proliferation was demonstrated on day 1 post infection, when a 4.2-fold increase in spirochetes was found in the skin and a 10-fold increase :in the blood, compared with control mice. The data represent the first direct evidence of a SAT effect of 1. ricinus SGE on infection with the Lyme disease agent B. burgdorferi.