WEITZEL, THOMAS
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WEITZEL, THOMAS
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thomas.weitzel@gmail.com
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Scopus Author ID
14007561700

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2023 2023 2022 2022 2021 2021 2020 2020 2019 2019 2018 2018 2017 2017 2016 2016 2015 2015 2014 2014 0.0 0.0 1.0 1.0 2.0 2.0 3.0 3.0 4.0 4.0 5.0 5.0

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Eco-epidemiology of rodent-associated trombiculid mites and infection with Orientia spp. in Southern Chile

2023 , María Carolina Silva de la Fuente , Caricia Pérez , Constanza Martínez-Valdebenito , Pérez Ball, Ruth , VIAL COX, MARIA CECILIA , Alexandr Stekolnikov , Katia Abarca , Gerardo Acosta-Jamett , WEITZEL, THOMAS , Jessica N. Ricaldi

Background Scrub typhus is a potentially severe infection caused by bacteria of the genus Orientia, endemic in Asia-Pacific and recently discovered in southern Chile. The presented study aimed to determine the prevalence and species richness of rodent-associated trombiculid mites and their infection with Orientia spp. in different areas of two regions in southern Chile. Methodology/Principal findings During summer 2020, trombiculid mites were collected from rodents captured in three areas in southern Chile known to be endemic for scrub typhus (Cochamó and Chiloé Island in the Los Lagos Region and Tortel in the Aysén Region). A total of 132 rodents belonging to five species were captured using Sherman-like traps; 89.4% were infested with trombiculids. Mite specimens were morphologically identified and subsequently tested by Orientia-specific qPCR. Six mite species were identified. Among chigger-infested rodents, 33.9% carried Orientia-positive mites; this rate was higher in Tortel (63.8%) than in Cochamó (45.0%) and Chiloé Island (2.0%). The analysis of individual mites (n = 901) revealed that 31.2% of Herpetacarus antarctica samples (n = 202) were positive for Orientia DNA; the prevalence was 7.0% in Paratrombicula neuquenensis (n = 213), 6.9% in Herpetacarus eloisae (n = 144), 3.6% in Argentinacarus expansus (n = 55), and 0% in Paratrombicula goffi (n = 110) and Quadraseta chiloensis (n = 177). The southernmost site (Tortel) showed the highest rates of trombiculid infestation, trombiculid load, and Orientia infection in the captured rodents. Conclusions/Significance Our study provides new insights into the trombiculid fauna and prevalence of Orientia in mites collected from wild rodents in southern Chile. Orientia DNA was detected in four of the six mite species. Rates of infestation, mite loads, and Orientia prevalences differed geographically and were highest in the Aysén Region. Our data improve our knowledge on possible vectors of scrub typhus and their distribution in Chile.

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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 , WEITZEL, THOMAS , Christina M. Farris , Gerardo Acosta-Jamett , Katia Abarca , Allen L. Richards

Scrub typhus is a potentially severe rickettsiosis, caused by Orientia tsutsugamushi in the Asia-Pacific region. Recently, however, two distinct pathogens, “Candidatus Orientia chuto” and “Candidatus Orientia chiloensis”, have been discovered in the Middle East and South America, respectively. Since the novel pathogens differ significantly from O. tsutsugamushi, 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 Orientia species. Based on a 94 bp sequence of the 16S rRNA gene (rrs), Orien16S recognized DNA samples from O. tsutsugamushi (n = 41), Ca. O. chiloensis (n = 5), and Ca. O. chuto (n = 1), but was negative for DNA preparations from closely related rickettsiae and other members of the order Rickettsiales (n = 22) as well as unrelated bacterial species (n = 11). After its implementation in Chile, the assay was verified, correctly identifying all tested eschar and buffy coat samples (n = 28) of clinical suspected cases. Furthermore, Orien16S detected Orientia DNA in trombiculid mites collected in endemic regions in southern Chile. The presented novel qPCR assay provides a useful tool for detecting Orientia and diagnosing scrub typhus from all geographical regions.

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Novel Vector of Scrub Typhus in Sub-Antarctic Chile: Evidence From Human Exposure

2021 , WEITZEL, THOMAS , María Carolina Silva-de la Fuente , Constanza Martínez-Valdebenito , Alexandr A Stekolnikov , Caricia Pérez , Ruth Pérez , Katia Abarca , VIAL COX, MARIA CECILIA , Gerardo Acosta-Jamett

Abstract The exposure of a research team to chigger mites in southern Chile allowed the first identification of a trombiculid species as vector and reservoir of scrub typhus outside the tsutsugamushi triangle, providing unique insights into the ecology and transmission of this recently discovered rickettsial infection in South America.

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Scrub typhus, an emerging infectious disease in Chile

2018 , Katia Abarca , WEITZEL, THOMAS , Constanza Martínez-Valdebenito , Gerardo Acosta-Jamett

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Scrub typhus risk in travelers to southern Chile

2019 , Thomas Weitzel , Gerardo Acosta-Jamett , Constanza Martínez-Valdebenito , Allen L. Richards , Martin P. Grobusch , Katia Abarca

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Absence of convincing evidence of Coxiella burnetii infection in Chile: A cross-sectional serosurvey among healthy adults in four different regions

2016 , WEITZEL, THOMAS , Javier López , Gerardo Acosta-Jamett , Sophie Edouard , Philippe Parola , Katia Abarca

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Human seroepidemiology of Rickettsia and Orientia species in Chile – A cross-sectional study in five regions

2020 , WEITZEL, THOMAS , Gerardo Acosta-Jamett , Ju Jiang , Constanza Martínez-Valdebenito , Christina M. Farris , Allen L. Richards , Katia Abarca

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Scrub Typhus in Continental Chile, 2016–2018

2019 , WEITZEL, THOMAS , Constanza Martínez-Valdebenito , Gerardo Acosta-Jamett , Ju Jiang , Allen L. Richards , Katia Abarca

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Chigger Mites (Acariformes: Trombiculidae) of Chiloé Island, Chile, With Descriptions of Two New Species and New Data on the GenusHerpetacarus

2020 , María Carolina Silva-de la Fuente , Alexandr A Stekolnikov , WEITZEL, THOMAS , Esperanza Beltrami , Constanza Martínez-Valdebenito , Katia Abarca , Gerardo Acosta-Jamett , Howard Ginsberg

AbstractThree species of chigger mites are recorded in our collections from four species of cricetid rodents on Chiloé Island (southern Chile, Los Lagos Region), an area endemic to scrub typhus (Orientia sp.). Two species are described as new—Herpetacarus (Abonnencia) eloisae sp. nov. and Quadraseta chiloensis sp. nov. One species, Paratrombicula goffiStekolnikov and González-Acuña 2012, is for the first time recorded on a mammal host (one species of cricetid rodent), and its distribution is extended to the Los Lagos Region of Chile. The genus ProschoengastiaVercammen-Grandjean, 1967 is synonymized with the subgenus Herpetacarus (Abonnencia)Vercammen-Grandjean, 1960, and four new combinations are established: Herpetacarus (Abonnencia) herniosa (Brennan and Jones, 1961), comb. nov., Herpetacarus (Abonnencia) insolita (Brennan and Jones, 1961), comb. nov., Herpetacarus (Abonnencia) macrochaeta (Brennan and Jones, 1961), comb. nov., and Herpetacarus (Abonnencia) antarctica (Stekolnikov and Gonzalez-Acuña, 2015), comb. nov.

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Molecular Description of a Novel Orientia Species Causing Scrub Typhus in Chile

2020 , Katia Abarca , Constanza Martínez-Valdebenito , Jenniffer Angulo , Ju Jiang , Christina M. Farris , Allen L. Richards , Gerardo Acosta-Jamett , WEITZEL, THOMAS

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