Electron Microscopic Observations of the Embryo <i>Leptotrombidium (Leptotrombidium) pallidum</i> Naturally Infected with <i>Rickettsia tsutsugamushi</i>

Urakami, Hiroshi; Takahashi, M.; Tamura, Akira; Hori, Eitaro

doi:10.1111/j.1348-0421.1988.tb01459.x

Cited by 10 publications

(1 citation statement)

References 6 publications

(3 reference statements)

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“…tsutsugamushi are vertically transmitted in the ovary of female mites to germ cells of progeny (27,30). In the following development, the multiplication of O. tsutsugamushi seems to be promoted particularly in the salivary gland cells, resulting in filling the cytoplasm with a number of O. tsutsugamushi by the time of feeding.…”

Section: Discussionmentioning

confidence: 99%

Electron Microscopic Observations of Orientia tsutsugamushi in Salivary Gland Cells of Naturally Infected Leptotrombidium pallidum Larvae during Feeding

Kadosaka

Kimura

2003

Microbiology and Immunology

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We performed a detailed electron microscopic observation on the escaping process of Orientia tsutsugamushi from the salivary gland cells of naturally infected trombiculid larvae into the acinar lumen of the gland during feeding on mice. In unfed larvae, many O. tsutsugamushi were intermingled with secretory granules in the cytoplasm of the salivary gland cell. O. tsutsugamushi was neither found in the acinar lumen nor observed escaping from the apical surface of the gland cell. In contrast, in the larvae fed on mice, many O. tsutsugamushi were observable in the acinar lumen. They were enveloped with the host glandular cell membrane. In salivary gland cells, secretory granules changed the distribution and accumulated in the apical region. In such cells, the majority of O. tsutsugamushi were found at the base of the cell. Some O. tsutsugamushi were pushing the glandular cell membrane outward in various degrees, showing different stages of escape. These findings suggest that larval feeding induced O. tsutsugamushi escape from salivary gland cells, that the escape was by budding, during which O. tsutsugamushi were enveloped in the host cell membrane, and that O. tsutsugamushi would be injected into the mouse skin as a mixture with mite saliva. The study also revealed the presence of many small vesicles that had the same cell wall structure as O. tsutsugamushi in the cytoplasm of the salivary gland cell. Most of them seemed to be products from degenerated Orientia.

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Section: Discussionmentioning

confidence: 99%

Electron Microscopic Observations of Orientia tsutsugamushi in Salivary Gland Cells of Naturally Infected Leptotrombidium pallidum Larvae during Feeding

Kadosaka

Kimura

2003

Microbiology and Immunology

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A comparative view of Rickettsia tsutsugamushi and the other groups of rickettsiae

1991

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Recent researches on the rickettsial group microorganisms are summarized in their comparative aspects of morphology, cultivation and multiplication, susceptibility to chemotherapeutics, chemical structure of envelopes, nucleic acid, protein constitution, and gene structures. From this overview, Rickettsia tsutsugamushi seems to have different properties from the others and should be reclassified into a new genus, and a new species name as Orientia tsutsugamushi is proposed.

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Takahashi

Urakami

Yoshida

et al. 1997

European Journal of Epidemiology

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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.

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Electron Microscopic Observations of the Embryo Leptotrombidium (Leptotrombidium) pallidum Naturally Infected with Rickettsia tsutsugamushi

Cited by 10 publications

References 6 publications

Electron Microscopic Observations of Orientia tsutsugamushi in Salivary Gland Cells of Naturally Infected Leptotrombidium pallidum Larvae during Feeding

Electron Microscopic Observations of Orientia tsutsugamushi in Salivary Gland Cells of Naturally Infected Leptotrombidium pallidum Larvae during Feeding

A comparative view of Rickettsia tsutsugamushi and the other groups of rickettsiae

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