title: Vector interactions and molecular adaptations of lyme disease and relapsing fever spirochetes associated with transmission by ticks.
abstract: Pathogenic spirochetes in the genus Borrelia are transmitted primarily by two families of ticks. The Lyme disease spirochete, Borrelia burgdorferi, is transmitted by the slow-feeding ixodid tick Ixodes scapularis, whereas the relapsing fever spirochete, B. hermsii, is transmitted by Ornithodoros hermsi, a fast-feeding argasid tick. Lyme disease spirochetes are generally restricted to the midgut in unfed I. scapularis. When nymphal ticks feed, the bacteria pass through the hemocoel to the salivary glands and are transmitted to a new host in the saliva after 2 days. Relapsing fever spirochetes infect the midgut in unfed O. hermsi but persist in other sites including the salivary glands. Thus, relapsing fever spirochetes are efficiently transmitted in saliva by these fast-feeding ticks within minutes of their attachment to a mammalian host. We describe how B. burgdorferi and B. hermsii change their outer surface during their alternating infections in ticks and mammals, which in turn suggests biological functions for a few surface-exposed lipoproteins.
authors.affiliation: Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA. tom_schwan@nih.gov
authors.forename: Tom G
authors.initials: TG
authors.lastname: Schwan
authors.forename: Joseph
authors.initials: J
authors.lastname: Piesman
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial; D000954:Antigens, Surface / Q000378:metabolism; D001096:Arachnid Vectors / Q000378:metabolism* / Q000382:microbiology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology / Q000378:metabolism*; D001428:Bacterial Vaccines; D001898:Borrelia / Q000254:growth & development* / Q000472:pathogenicity*; D025065:Borrelia burgdorferi / Q000254:growth & development / Q000472:pathogenicity; D006801:Humans; D018884:Ixodes / Q000378:metabolism / Q000382:microbiology; D008074:Lipoproteins; D008193:Lyme Disease / Q000276:immunology / Q000378:metabolism* / Q000517:prevention & control / Q000635:transmission*; D008322:Mammals; D026861:Ornithodoros / Q000378:metabolism / Q000382:microbiology; D012061:Relapsing Fever / Q000276:immunology / Q000378:metabolism* / Q000517:prevention & control / Q000635:transmission*
chemical_list: D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D008074:Lipoproteins; C072045:OspA protein; C079616:OspC protein; C077030:OspB protein, Borrelia burgdorferi