RAPID DISSEMINATION BY THE AGENT OF LYME-DISEASE IN HOSTS THAT PERMITFULMINATING INFECTION

We determined whether the agent of Lyme disease (Borrelia burgdorferi) disseminates more rapidly following deposition in hosts that permit f ulminating infection than in hosts in which infection is relatively be nign. Thus, individual infected nymphal deer ticks (Ixodes dammini) we re permitted to engorge on the ears of C3H mice, and the site of attac hment was excised at intervals thereafter. Infection in each mouse was determined by serology and by examining previously noninfected ticks that had engorged on these mice. These results were compared with data obtained similarly by using the CD-1 strain of mice in which the agen t is relatively nonpathogenic. When the site of inoculation was ablate d within 2 days after the infected tick became replete, dissemination was aborted. Spirochetemia could not be demonstrated in any of these m ice. We conclude that Lyme disease spirochetes disseminate from the fe eding lesion of an infecting tick more rapidly in certain highly spiro chete-susceptible mice than in others in which pathogenesis is less se vere.