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Ultrastructural and Genetic Evidence of a Reptilian Tick, Aponomma hydrosauri , as a Host of Rickettsia honei in Australia
Author(s) -
WHITWORTH TED,
POPOV VSEVOLOD,
HAN VIOLET,
BOUYER DONALD,
STENOS JOHN,
GRAVES STEPHEN,
NDIP LUCY,
WALKER DAVID
Publication year - 2003
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2003.tb07339.x
Subject(s) - rickettsia , spotted fever , biology , midgut , transovarial transmission , tick , virology , rocky mountain spotted fever , rickettsiosis , zoology , vector (molecular biology) , malpighian tubule system , microbiology and biotechnology , gene , genetics , ecology , virus , larva , recombinant dna
A bstract : In 1993, a novel rickettsia was isolated from the blood of inhabitants of Flinders Island, Australia, with acute febrile illnesses. This rickettsia was found to be a new species of spotted fever group (SFG) rickettsia, eventually named Rickettsia honei . The suspected ectoparasite vector of this rickettsia has yet to be identified. The purpose of this study was to evaluate the presence of this rickettsial species in a suspected tick vector, Aponomma hydrosauri , by DNA sequencing and electron microscopy (EM). Ticks collected from an Australian blue‐tongued lizard on Flinders Island and a copperhead snake in Tasmania were demonstrated to be infected with R. honei by PCR, DNA sequencing, and EM. Rickettsiae were found in ultrathin sections of salivary glands, malpighian tubules, and midgut epithelial cells. In a previous study with a R. honei ‐infected tick from Flinders Island, rickettsiae were found in the nuclei of midgut epithelial cells, and EM also revealed the presence of rickettsiae in the cytosol of oocytes and immature eggs, suggesting transovarial transmission. These results implicate A. hydrosauri as a possible host of R. honei on Flinders Island and Tasmania and also provide evidence favoring transovarial maintenance of R. honei .