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 ticks. C3H/HeN mice were injected intradermally with 1.5 x 10(3) spirochetes mixed with 40 microg 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 I. ricinus SGE on infection with the Lyme disease agent B. burgdorferi.

Faculty of Biological Sciences University of South Bohemia and Institute of Parasitology Academy of Sciences of the Czech Republic Branisovská 31 370 05 Cesk6é Budejovice Czech Republic

The crystal structures of two salivary cystatins from the tick Ixodes scapularis and the effect of these inhibitors on the establishment of Borrelia burgdorferi infection in a murine model