title: Differential infectivity of the Lyme disease spirochete Borrelia burgdorferi derived from Ixodes scapularis salivary glands and midgut.
abstract: Blood fed nymphal Ixodes scapularis Say infected with Borrelia burgdorferi were dissected to obtain salivary gland and midgut extracts. Extracts were inoculated into C3H/HeJ mice, and ear, heart, and bladder were cultured to determine comparative infectivity. Aliquots of extracts were then analyzed by quantitative polymerase chain reaction to determine the number of spirochetes inoculated into mice. A comparative median infectious dose (ID50) was determined for both salivary gland and midgut extract inoculations. Our data demonstrated a statistically significant difference (P < 0.002) in the ID50 derived from salivary gland (average = 18) versus midgut (average = 251) extracts needed to infect susceptible mice. A rationale for the differential infectivity of salivary and midgut derived spirochetes is discussed.
authors.affiliation: Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80522, USA.
authors.forename: C M R
authors.initials: CM
authors.lastname: Lima
authors.forename: N S
authors.initials: NS
authors.lastname: Zeidner
authors.forename: C B
authors.initials: CB
authors.lastname: Beard
authors.forename: C A G
authors.initials: CA
authors.lastname: Soares
authors.forename: M C
authors.initials: MC
authors.lastname: Dolan
authors.forename: G
authors.initials: G
authors.lastname: Dietrich
authors.forename: J
authors.initials: J
authors.lastname: Piesman
mesh_terms: D000818:Animals; D025065:Borrelia burgdorferi / Q000302:isolation & purification* / Q000472:pathogenicity*; D007422:Intestines / Q000382:microbiology; D018884:Ixodes / Q000382:microbiology*; D051379:Mice; D008809:Mice, Inbred C3H; D012469:Salivary Glands / Q000382:microbiology