INTERRELATIONSHIPS BETWEEN DIFFERENT BORRELIA GENOSPECIES AND THEIR PRINCIPAL VECTORS

Under conditions of similar prevalence of Borrelia infection in tick p opulations, a generalized infection with the presence of spirochetes i n the salivary glands develops much more frequently in the unfed adult Ixodes persulcatus ticks, infected by Borrelia afzelii and Borrelia g arinii in Russian natural foci, than in I. scapularis ticks from the n ortheastern United States, infected with Borrelia burgdorferi sensu st ricto. During the first two to three days after infected I. persulcatu s begin to engorge, the proportion of ticks with spirochetes in the sa livary glands did not increase. In I. persulcatus, therefore, Borrelia migration from the gut into the salivary glands at the beginning of t he brood-sucking phase is not a necessary or even important condition for Borrelia transmission wi th saliva. These data provide evidence fo r different interrelationships between particular Borrelia genospecies and their principal tick vectors.