Universidad del Desarrollo

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Surveillance of vector-borne infections: Dogs as sentinel animals for Orientia and Rickettsia exposure in five regions in Chile
(Elsevier BV, 2026-06)
Paulina López-Silva
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Constanza Martínez-Valdebenito
;
Ju Jiang
;
Katia Abarca
;
Javier López
1
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Hosts and vectors of scrub typhus in Chile: epidemiological study and molecular analyses of Orientia infection in rodents and rodent-associated mites
(Springer Science and Business Media LLC, 2024-12-18)
Constanza Martínez-Valdebenito
;
Gerardo Acosta-Jamett
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Rayitray Abello
;
Ju Jiang
;
Allen L. Richards
<jats:title>Abstract</jats:title><jats:p><jats:italic>Candidatus</jats:italic> Orientia chiloensis causes scrub typhus over a wide geographical range in southern Chile. The life cycle, including vectors and reservoirs of this novel rickettsial pathogen, is incompletely understood. We analyzed rodent tissue and rodent-associated mite samples collected during a field study in six localities on Chiloé Island, where human scrub typhus cases have occurred. Using molecular methods, we detected <jats:italic>Orientia</jats:italic> DNA in 24.8% of rodents, belonging to five of seven captured species. <jats:italic>Orientia</jats:italic>-infection rates showed geographical variations, but were not influenced by rodent species, sex, age, and mite infestation. Phylogenetic analysis showed that <jats:italic>Orientia</jats:italic> sequences from trombiculid mites (<jats:italic>Proschoengastia eloisae</jats:italic>) were identical to those from scrub typhus patients from the same region. The results suggest that these rodent-associated mites serve as vectors and play an important role in the ecology of scrub typhus in southern Chile. Further studies are required to determine whether <jats:italic>Orientia</jats:italic>-infected rodents can also serve as reservoir of <jats:italic>Orientia</jats:italic> in Chile.</jats:p> <jats:p><jats:bold>Graphical Abstract</jats:bold></jats:p>
1Scopus© Citations 8
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Marginalized mites: Neglected vectors of neglected diseases
(2020)
WEITZEL, THOMAS
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Benjamin L. Makepeace
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Ivo Elliott
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Kittipong Chaisiri
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Allen L. Richards
1Scopus© Citations 15 2
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Identification of trombiculid mites (Acari: Trombiculidae) on rodents from Chiloé Island and molecular evidence of infection with Orientia species
(2020)
Gerardo Acosta-Jamett
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Constanza Martínez-Valdebenito
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Esperanza Beltrami
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María Carolina Silva-de La Fuente
;
Ju Jiang
23 1Scopus© Citations 42
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Molecular Description of a Novel <i>Orientia</i> Species Causing Scrub Typhus in Chile
(2020)
Katia Abarca
;
Constanza Martínez-Valdebenito
;
Jenniffer Angulo
;
Ju Jiang
;
Christina M. Farris
1Scopus© Citations 78 1
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Development of a New Genus-Specific Quantitative Real-Time PCR Assay for the Diagnosis of Scrub Typhus in South America
(2022)
Ju Jiang
;
Constanza Martínez-Valdebenito
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WEITZEL, THOMAS
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Christina M. Farris
;
Gerardo Acosta-Jamett
<jats:p>Scrub typhus is a potentially severe rickettsiosis, caused by <jats:italic>Orientia tsutsugamushi</jats:italic> in the Asia-Pacific region. Recently, however, two distinct pathogens, “<jats:italic>Candidatus</jats:italic> Orientia chuto” and “<jats:italic>Candidatus</jats:italic> Orientia chiloensis”, have been discovered in the Middle East and South America, respectively. Since the novel pathogens differ significantly from <jats:italic>O. tsutsugamushi</jats:italic>, many established diagnostic methods are unreliable. This work describes the development and validation of a new quantitative real-time PCR (qPCR) assay (Orien16S) for the detection of all known <jats:italic>Orientia</jats:italic> species. Based on a 94 bp sequence of the 16S rRNA gene (<jats:italic>rrs</jats:italic>), Orien16S recognized DNA samples from <jats:italic>O. tsutsugamushi</jats:italic> (<jats:italic>n</jats:italic> = 41), <jats:italic>Ca.</jats:italic> O. chiloensis (<jats:italic>n</jats:italic> = 5), and <jats:italic>Ca.</jats:italic> O. chuto (<jats:italic>n</jats:italic> = 1), but was negative for DNA preparations from closely related rickettsiae and other members of the order Rickettsiales (<jats:italic>n</jats:italic> = 22) as well as unrelated bacterial species (<jats:italic>n</jats:italic> = 11). After its implementation in Chile, the assay was verified, correctly identifying all tested eschar and buffy coat samples (<jats:italic>n</jats:italic> = 28) of clinical suspected cases. Furthermore, Orien16S detected <jats:italic>Orientia</jats:italic> DNA in trombiculid mites collected in endemic regions in southern Chile. The presented novel qPCR assay provides a useful tool for detecting <jats:italic>Orientia</jats:italic> and diagnosing scrub typhus from all geographical regions.</jats:p>
1Scopus© Citations 14 1
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Human seroepidemiology of Rickettsia and Orientia species in Chile – A cross-sectional study in five regions
(2020)
WEITZEL, THOMAS
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Gerardo Acosta-Jamett
;
Ju Jiang
;
Constanza Martínez-Valdebenito
;
Christina M. Farris
11 1Scopus© Citations 11

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