Article

European Journal of Epidemiology

, Volume 13, Issue 1, pp 19-23

First online:

Occurrence of high ratio of males after introduction of minocycline in a colony of leptotrombidium fletcheri infected with orientia tsutsugamushi

  • Mamoru TakahashiAffiliated withKawagoe Agricultural Senior High SchoolDepartment of Medical Zoology, Saitama Medical School
  • , Hiroshi UrakamiAffiliated withDepartment of Microbiology, Niigata College of Pharmacy
  • , Yoshiya YoshidaAffiliated withDivision of Virology, Kanagawa Prefectural Public Health Laboratory
  • , Yumiko FuruyaAffiliated withDivision of Virology, Kanagawa Prefectural Public Health Laboratory
  • , Hitoko MisumiAffiliated withLaboratory of Chemistry, Kagawa Nutrition University, Komagome, Toshima-Ku, Tokyo
  • , Eitaro HoriAffiliated withDepartment of Medical Zoology, Saitama Medical School
  • , Akiyoshi KawamuraAffiliated withInstitute of Medical Science, The University of Tokyo
  • , Hiroshi TanakaAffiliated withInstitute of Medical Science, The University of Tokyo

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

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 generations 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.

Infected colony Leptotrombidium fletcheri Minocycline Orientia tsutsugamushi Sex ratio