title: Occurrence of high ratio of males after introduction of minocycline in a colony of Leptotrombidium fletcheri infected with Orientia tsutsugamushi.
abstract: In colonies of Leptotrombidium fletcheri mites infected with Orientia tsutsugamushi (Ot), the agent of scrub typhus, males rarely appear. In the present study, the development of a high ratio of males was observed after introduction of minocycline (MC). A high dose of MC was injected subcutaneously into a mouse, and by feeding unfed larvae from an infected mite colony on this mouse, the Ot in the mites were successfully killed. Of a total of 130 unfed larvae attached to the mouse, 29 developed into females; of these, 9 laid an average of 112.4 eggs/female. Unfed larvae in the succeeding generations were attached to untreated mice. All adults in the P and F1 generation were females, and males started to appear at the F2 generation. The ratio of males to females was 332:7, 108:13, 263:61 and 71:9 at the F2, F3, F4 and F5 generations, respectively. These data suggest that Ot in the ovary or gonad may suppress the development of males.
authors.affiliation: Kawagoe Agricultural Senior High School, Saitama, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Urakami
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Y
authors.initials: Y
authors.lastname: Furuya
authors.forename: H
authors.initials: H
authors.lastname: Misumi
authors.forename: E
authors.initials: E
authors.lastname: Hori
authors.forename: A
authors.initials: A
authors.lastname: Kawamura
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004199:Disease Vectors; D005260:Female; D007814:Larva; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D008911:Minocycline / Q000494:pharmacology*; D012285:Orientia tsutsugamushi / Q000187:drug effects / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012744:Sex Ratio; D014324:Trombiculidae / Q000187:drug effects / Q000254:growth & development / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D008911:Minocycline