title: Characterization of spotted fever group rickettsiae in flea and tick specimens from northern Peru.
abstract: Evidence of spotted fever group (SFG) rickettsiae was obtained from flea pools and individual ticks collected at three sites in northwestern Peru within the focus of an outbreak of febrile disease in humans attributed, in part, to SFG rickettsia infections. Molecular identification of the etiologic agents from these samples was determined after partial sequencing of the 17-kDa common antigen gene (htrA) as well as pairwise nucleotide sequence homology with one or more of the following genes: gltA, ompA, and ompB. Amplification and sequencing of portions of the htrA and ompA genes in pooled samples (2 of 59) taken from fleas identified the pathogen Rickettsia felis. Four tick samples yielded molecular evidence of SFG rickettsiae. Fragments of the ompA (540-bp) and ompB (2,484-bp) genes were amplified from a single Amblyomma maculatum tick (tick 124) and an Ixodes boliviensis tick (tick 163). The phylogenetic relationships between the rickettsiae in these samples and other rickettsiae were determined after comparison of their ompB sequences by the neighbor-joining method. The dendrograms generated showed that the isolates exhibited close homology (97%) to R. aeschlimannii and R. rhipicephali. Significant bootstrap values supported clustering adjacent to this nodule of the SFG rickettsiae. While the agents identified in the flea and tick samples have not been linked to human cases in the area, these results demonstrate for the first time that at least two SFG rickettsia agents were circulating in northern Peru at the time of the outbreak. Furthermore, molecular analysis of sequences derived from the two separate species of hard ticks identified a possibly novel member of the SFG rickettsiae.
authors.affiliation: U.S. Naval Medical Research Center Detachment, Lima, Peru. blair@namru2.med.NAVY.mil
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Blair
authors.forename: Ju
authors.initials: J
authors.lastname: Jiang
authors.forename: George B
authors.initials: GB
authors.lastname: Schoeler
authors.forename: Cecilia
authors.initials: C
authors.lastname: Moron
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Anaya
authors.forename: Manuel
authors.initials: M
authors.lastname: Cespedes
authors.forename: Christopher
authors.initials: C
authors.lastname: Cruz
authors.forename: Vidal
authors.initials: V
authors.lastname: Felices
authors.forename: Carolina
authors.initials: C
authors.lastname: Guevara
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mendoza
authors.forename: Pablo
authors.initials: P
authors.lastname: Villaseca
authors.forename: John W
authors.initials: JW
authors.lastname: Sumner
authors.forename: Allen L
authors.initials: AL
authors.lastname: Richards
authors.forename: James G
authors.initials: JG
authors.lastname: Olson
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis; D008969:Molecular Sequence Data; D010568:Peru; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012281:Rickettsia / Q000145:classification* / Q000235:genetics; D012373:Rocky Mountain Spotted Fever / Q000382:microbiology* / Q000635:transmission; D005423:Siphonaptera / Q000145:classification / Q000382:microbiology*; D013987:Ticks / Q000145:classification / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial