title: Accelerated transmission of Lyme disease spirochetes by partially fed vector ticks.
abstract: To determine how rapidly Lyme disease spirochetes (Borrelia burgdorferi) can be transmitted by partially fed vector ticks (Ixodes dammini), attached nymphs were removed from their hosts at various intervals post-attachment and subsequently permitted to re-feed to repletion on noninfected mice. We confirm previous reports that ticks deposit Lyme disease spirochetes in the skin of their hosts mainly after 2 days of attachment. Those that have been removed from a host within this interval can reattach and commence feeding. Spirochete-infected nymphs that have previously been attached to a host for 1 day become infectious to other hosts within another day. Noninfected nymphs acquire infection from spirochete-infected hosts within a day of attachment and become infectious to other hosts 3 to 5 days later. Virtually all ticks transmitted infection when reattaching after first feeding for 2 days. We conclude that partially fed nymphal ticks transmit spirochetal infection more rapidly than do ticks that have never been attached to a host and that infected ticks become infectious before they molt.
authors.affiliation: Department of Tropical Public Health, Harvard School of Public Health, Boston, Massachusetts 02115.
authors.forename: C M
authors.initials: CM
authors.lastname: Shih
authors.forename: A
authors.initials: A
authors.lastname: Spielman
mesh_terms: D000818:Animals; D007303:Insect Vectors; D008193:Lyme Disease / Q000635:transmission*; D051379:Mice; D013987:Ticks / Q000382:microbiology*