The Life Cycle of the Scrub Typhus Chigger Mite, Trombicula akamushi1

Neal, Talmadge J.; Barnett, Herbert C.

doi:10.1093/aesa/54.2.196

Cited by 12 publications

(7 citation statements)

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“…2 A,C) similar to what was earlier observed in the trombiculid mite Ascoschoengastia indica (Wharton 1946). This prelarva has been termed traditionally as`deutovum' by earlier authors on trombiculids (Ewing 1944;Michener 1946;Wharton 1946;Neal and Barnett 1961), although it has been known for a long time that this organism represents the first but strongly regressed larval instar (Grandjean 1938b). The observations made with a dissecting microscope show a smooth and shiny prelarva, while its colour changes from light yellow to deep orange as the development progressed.…”

Section: Resultssupporting

confidence: 75%

“…The life cycle of mites from the order Acariformes is comprised of an egg and six active instars, or stages of post-embryonic development ± two hexapod larvae, three octopod nymphs and adult mites (see Grandjean 1938b;Lange 1960;Hammen 1964;Trave Â 1976;Bo È ttger 1977;Kethley 1990b). In some groups of trombidiform mites (suborder Actinedida), such as Nanorchestidae (Kethley 1991), Ereynetidae (Fain 1972;Baker 1973;Andre and Fain 1991;Andre 1992), Pterygosomatidae (Newell 1973;Kethley 1991), Trombidiidae (Singer 1971;Robaux 1974), Trombiculidae (Ewing 1944;Michener 1946;Wharton 1946;Neal and Barnett 1961;Johnston and Wacker 1967) and water mites belonging to the phalanx Hydrachnidia (Bottger 1977) there is a regression, or`calyptostatic inhibition' (Coineau 1974), not only the first larval instar (pre-larva), but also the first (protonymph) and the third (tritonymph) nymphal instars. Such inhibition results in the alternation of active and quiescent (inactive, regressive) instars and has been thought to perform the progressive phylogenetic compression and reduction of development (Reuter 1909;Knu È lle 1961).…”

Section: Introductionmentioning

confidence: 99%

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External morphology of the quiescent instars of trombiculid mites (Acariformes: Trombiculidae) with notes on their moulting processes

1999

Acta Zoologica

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Section: Resultssupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

External morphology of the quiescent instars of trombiculid mites (Acariformes: Trombiculidae) with notes on their moulting processes

1999

Acta Zoologica

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“…Many aspects of the life-cycle of chiggers are well understood from laboratory colony studies, although how this may vary in nature is not. Neal & Barnett [48] provided a detailed account of the life-cycle of Trombicula akamushi in laboratory conditions. Males produce stalked spermatophores that are deposited in the environment and taken up by females to fertilise their eggs.…”

Section: Resultsmentioning

confidence: 99%

“…Culex mosquito eggs), or recently deceased or quiescent soft-bodied insects such as Collembola [49, 50]. Two weeks later the nymph develops into the tritonymph (teleiophane), lasting about 2 weeks from which the adult finally emerges [9, 48, 51–56] (Fig. 15).…”

Section: Resultsmentioning

confidence: 99%

Scrub typhus ecology: a systematic review of Orientia in vectors and hosts

et al. 2019

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Scrub typhus, caused by Orientia tsutsugamushi, is an important and neglected vector-borne zoonotic disease with an expanding known distribution. The ecology of the disease is complex and poorly understood, impairing discussion of public health interventions. To highlight what we know and the themes of our ignorance, we conducted a systematic review of all studies investigating the pathogen in vectors and non-human hosts. A total of 276 articles in 7 languages were included, with 793 study sites across 30 countries. There was no time restriction for article inclusion, with the oldest published in 1924. Seventy-six potential vector species and 234 vertebrate host species were tested, accounting for over one million trombiculid mites (‘chiggers’) and 83,000 vertebrates. The proportion of O. tsutsugamushi positivity was recorded for different categories of laboratory test and host species. Vector and host collection sites were geocoded and mapped. Ecological data associated with these sites were summarised. A further 145 articles encompassing general themes of scrub typhus ecology were reviewed. These topics range from the life-cycle to transmission, habitats, seasonality and human risks. Important gaps in our understanding are highlighted together with possible tools to begin to unravel these. Many of the data reported are highly variable and inconsistent and minimum data reporting standards are proposed. With more recent reports of human Orientia sp. infection in the Middle East and South America and enormous advances in research technology over recent decades, this comprehensive review provides a detailed summary of work investigating this pathogen in vectors and non-human hosts and updates current understanding of the complex ecology of scrub typhus. A better understanding of scrub typhus ecology has important relevance to ongoing research into improving diagnostics, developing vaccines and identifying useful public health interventions to reduce the burden of the disease.

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“…In the case of the species E. alfreddugesi and E. splendens, both prefer to feed of Collembola eggs, as well as Culex and Aedes. Neal and Barnett (1961) worked with the species Trombicula akamushi Brumpt, 1910, reporting the importance for controlling the humidity and lighting. In Brazil, Jacinavicius et al, 2017 2 obtained nymphs Quadraseta brasiliensis Goff and Gettinger, 1989 in laboratory conditions from engorged larvae.…”

Section: Biologymentioning

confidence: 99%

<b>Chigger mites (Trombidiformes: Trombiculidae) of birds from Brazilian southeastern</b>: morphological studies and investigation of the presence of <i>Rickettsia</i> spp.

Bassini‐Silva¹

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RESUMO BASSINI-SILVA, R. Ácaros trombiculideos (Trombidiformes: Trombiculidae) de aves do sudeste brasileiro: estudos morfológicos e investigação da presença de Rickettsia spp. [Chigger mites (Trombidiformes: Trombiculidae) of birds from Brazilian southeastern: morphological studies and investigation of the presence of Rickettsia spp.]. 2017. 298 f. Dissertação (Mestrado em Ciências) -Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, 2017. O Brasil possui 58 espécies de ácaros trombiculídeos parasitando diferentes grupos animais. E destas, somente 6 espécies foram reportadas para aves, sendo 1 de Apolonia, 2 de Eutrombicula, 1 de Neoschoengastia e 2 de Parasecia. As larvas de trombiculídeos provocam lesões profundas e reações cutâneas no hospedeiro, sendo por muitas vezes citados como vetores de agentes patogênicos. Nos Estados Unidos, os departamentos de saúde pública se depararam com a necessidade de catalogação e conhecimento da biologia desses ácaros por serem considerados potenciais vetores de Rickettsia spp. No Brasil, os primeiros casos de Febre Maculosa Brasileira (FMB) diagnosticados em São Paulo, foram associados a esses ácaros porque terem sido encontrados em focos da doença. No entanto, o seu papel na epidemiologia da riquetsiose não foi confirmado. Outra preocupação é a dermatite causada pela mordida desses ácaros, popularmente conhecida como trombiculíase. Como é bem conhecido, trombiculídeos não são específicos e vários casos de mordidas em humanos já foram relatados. Dessa forma, a proposta do presente estudo é conhecer a situação atual dos trombiculídeos de aves, esclarecer os aspectos de sua complexidade taxonômica, bem como fornecer informações sobre sua participação na epidemiologia de riquétsias em algumas localidades da região sudeste do país. Do material examinado no presente estudo foram identificadas 8 espécies: Blankaartia shatrovi sp. n., Blankaartia sinnamaryi, Microtrombicula sp. n., Eutrombicula tinami, Eutrombicula goeldii, Parasecia sp. n.1, Parasecia sp. n.2, Parasecia sp. n.3. Os ácaros mantidos em álcool absoluto foram submetidos à extração de DNA e investigação da presença de Rickettsia. Uma das amostras aprentou 100% para Rickettsia felis. Portanto, para o Brazil agora, temos 13 espécies descritas para todo o território nacional, com excessão da região Centro-Oeste, e, além disso, o primeiro registro da presença de Rickettsia em ácaros trombiculídeos da América do Sul. ABSTRACT BASSINI-SILVA, R. Chigger mites (Trombidiformes: Trombiculidae) of birds from Brazilian southeastern: morphological studies and investigation of the presence of Rickettsia spp. [Ácaros trombiculideos (Trombidiformes: Trombiculidae) de aves do sudeste brasileiro: estudos morfológicos e investigação da presença de Rickettsia spp.]. 2017. 298 f. Dissertação (Mestrado em Ciências) -Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, 2017.Brazil has 58 species of chigger mites parasitizing different animal groups. Of these, only 6 species we...

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The Life Cycle of the Scrub Typhus Chigger Mite, Trombicula akamushi1

Cited by 12 publications

References 0 publications

External morphology of the quiescent instars of trombiculid mites (Acariformes: Trombiculidae) with notes on their moulting processes

External morphology of the quiescent instars of trombiculid mites (Acariformes: Trombiculidae) with notes on their moulting processes

Scrub typhus ecology: a systematic review of Orientia in vectors and hosts

<b>Chigger mites (Trombidiformes: Trombiculidae) of birds from Brazilian southeastern</b>: morphological studies and investigation of the presence of <i>Rickettsia</i> spp.

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