Serologic Evidence of Scrub Typhus in the Peruvian Amazon

Kocher, Claudine; Jiang, Ju; Morrison, Amy C.; Oré, Roger M. Castillo; Leguía, Mariana; Loyola, Steev; Ampuero, Julia S.; Céspedes, Manuel; Halsey, Eric S.; Bausch, Daniel G.; Richards, Allen L.

doi:10.3201/eid2308.170050

Cited by 43 publications

(39 citation statements)

References 16 publications

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“…Since then, serological and molecular evidence of scrub typhus in Africa has been accumulating (7-9, 19, 20). More recent studies have revealed existence of endemic scrub typhus in South America (21)(22)(23). Our study attests to these claims and provides molecular evidence for the existence of Orientia in Kenya that is more similar to O. chuto than to O. tsutsugamushi.…”

Section: Discussionsupporting

confidence: 85%

Identification and Characterization of Orientia chuto in Trombiculid Chigger Mites Collected from Wild Rodents in Kenya

et al. 2018

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We present data that concurs with the reported geographical expansion of scrub typhus outside the “Tsutsugamushi Triangle” and addition ofOrientia chutoas a second species in theOrientiagenus. Wild rodents were caught in Marigat, Baringo County, Kenya, and ectoparasites, including chiggers, were recovered. Rodent and chigger species were identified by taxonomic features. DNA was extracted from the chiggers and used to amplify and/or sequence the 47-kDa high temperature transmembrane protein (TSA47), the 56-kDa type-specific antigen (TSA56), and the 16S rRNA (rrs)Orientiagenes. The main rodent hosts identified wereAcomys wilsoni,Crocidurasp., andMastomys natalensis, which accounted for 59.2% of the total collection. Of these,A. wilsoniandM. natalensisharbored most of the chiggers that belonged to theNeotrombiculaandMicrotrombiculagenera. A pool of chiggers from one ofM. natalensiswas positive forOrientiaby TSA47 PCR, butOrientiadid not amplify with the TSA56 primers. On sequencing the 850 bp of the TSA47 gene, the closest phylogenetic relative wasO. chuto, with 97.65% sequence homology compared to 84.63 to 84.76% forO. tsutsugamushi. 16S rRNA deep sequencing also revealedO. chutoas the closest phylogenetic relative, with 99.75% sequence homology. These results and the existing immunological and molecular reports are strongly suggestive of the existence ofOrientiaspecies in Kenya.

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Section: Discussionsupporting

confidence: 85%

Identification and Characterization of Orientia chuto in Trombiculid Chigger Mites Collected from Wild Rodents in Kenya

et al. 2018

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“…More than 1 million new cases are diagnosed annually. The disease occurs primarily in the Asia-Pacific, but also in the Middle East, Africa, and South America, threatening one-third of the world's population (9)(10)(11). Scrub typhus presents as an acute febrile illness accompanied by several nonspecific clinical manifestations and often a maculopapular rash.…”

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confidence: 99%

The Obligate Intracellular Bacterium Orientia tsutsugamushi Targets NLRC5 To Modulate the Major Histocompatibility Complex Class I Pathway

et al. 2019

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Orientia tsutsugamushiis an obligate intracellular bacterium that infects mononuclear and endothelial cells to cause the emerging global health threat scrub typhus. The ability ofO. tsutsugamushito survive in monocytes facilitates bacterial dissemination to endothelial cells, which can subsequently lead to several potentially fatal sequelae. As a strict intracellular pathogen that lives in the cytoplasm of host cells,O. tsutsugamushihas evolved to counter adaptive immunity. How the pathogen does so and the outcome of this strategy in monocytes versus endothelial cells are poorly understood. This report demonstrates thatO. tsutsugamushireduces cellular levels of NOD-, LRR-, and CARD-containing 5 (NLRC5), a recently identified specific transactivator of major histocompatibility complex class I (MHC-I) component gene expression, to inhibit MHC-I biosynthesis. Importantly, the efficacy of this approach varies with the host cell type infected. In nonprofessional antigen-presenting HeLa and primary human aortic endothelial cells, theO. tsutsugamushi-mediated reduction of NLRC5 results in lowered MHC-I component transcription and, consequently, lower total and/or surface MHC-I levels throughout 72 h of infection. However, in infected THP-1 monocytes, which are professional antigen-presenting cells, the reductions in NLRC5 and MHC-I observed during the first 24 h reverse thereafter.O. tsutsugamushiis the first example of a microbe that targets NLRC5 to modulate the MHC-I pathway. The differential ability ofO. tsutsugamushito modulate this pathway in nonprofessional versus professional antigen-presenting cells could influence morbidity and mortality from scrub typhus.

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“…Scrub typhus is an acute, potentially lethal febrile disease transmitted by chigger mites (Trombiculidae) infected with the rickettsia Orientia tsutsugamushi (OT) and has long been thought confined to Asia and northern Australia [16]. However, this disease has recently been identified in South America (Chile and Peru [17][18][19]) and Africa (Kenya and Djibouti [20][21][22]), and is also emerging in some endemic regions, such as China and Korea [23][24][25][26][27]. The life cycle of chigger mites include the egg, larva, nymph, and adult; only the larval stage (chiggers thereafter) is parasitic.…”

Section: Introductionmentioning

confidence: 99%

Invasive plants facilitated by socioeconomic change harbor vectors of scrub typhus and spotted fever

et al. 2020

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Background Ecological determinants of most emerging vector-borne diseases are understudied, particularly for neglected tropical disease. Moreover, although socioeconomic impacts can have significant downstream effects on human risks to vector-borne diseases via a change in land cover, particularly facilitating the invasion of exotic plants, related studies remains very scarce. Scrub typhus and spotted fever are neglected diseases emerging around the globe and are transmitted by chigger mites and ticks infective of Orientia tsutsugamushi and Rickettsia spp., respectively, with small mammals as the primary hosts of both vectors.

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Serologic Evidence of Scrub Typhus in the Peruvian Amazon

Cited by 43 publications

References 16 publications

Identification and Characterization of Orientia chuto in Trombiculid Chigger Mites Collected from Wild Rodents in Kenya

Identification and Characterization of Orientia chuto in Trombiculid Chigger Mites Collected from Wild Rodents in Kenya

The Obligate Intracellular Bacterium Orientia tsutsugamushi Targets NLRC5 To Modulate the Major Histocompatibility Complex Class I Pathway

Invasive plants facilitated by socioeconomic change harbor vectors of scrub typhus and spotted fever

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