Browsing by Author "Jiang, Ju"
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- ItemCanine seroprevalence to Orientia species in southern Chile: A cross-sectional survey on the Chiloe A Island(2018) Weitzel, Thomas; Jiang, Ju; Acosta-Jamett, Gerardo; Martinez-Valdebenito, Constanza; Lopez, Javier; Richards, Allen L.; Abarca Villaseca, Katia
- ItemDevelopment of a New Genus-Specific Quantitative Real-Time PCR Assay for the Diagnosis of Scrub Typhus in South America(2022) Jiang, Ju; Martinez-Valdebenito, Constanza; Weitzel, Thomas; Farris, Christina M.; Acosta-Jamett, Gerardo; Abarca, Katia; Richards, Allen L.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.
- ItemEndemic Scrub Typhus-like Illness, Chile(Centers for Disease Control an Prevention, 2011) Balcells Marty, María Elvira; Rabagliati Borie, Ricardo Miguel; García Cañete, Patricia Del Carmen; Poggi Mayorga, Helena Loreto; Oddo Benavides, Carlos David; Concha Rogazy, Marcela Andrea; Abarca Villaseca, Katia; Jiang, Ju; Kelly, Daryl J.; Richards, Allen L.; Fuerst, Paul A.We report a case of scrub typhus in a 54-year-old man who was bitten by several terrestrial leeches during a trip to Chiloe Island in southern Chile in 2006. A molecular sample, identified as related to Orientia tsutsugamushi based on the sequence of the 16S rRNA gene, was obtained from a biopsy specimen of the eschar on the patient's leg. Serologic analysis showed immunoglobulin G conversion against O. tsutsugamushi whole cell antigen. This case and its associated molecular analyses suggest that an Orientia-like agent is present in the Western Hemisphere that can produce scrub typhus-like illness. The molecular analysis suggests that the infectious agent is closely related, although not identical, to members of the Orientia sp. from Asia.
- ItemHosts and vectors of scrub typhus in Chile: epidemiological study and molecular analyses of Orientia infection in rodents and rodent-associated mites(2024) Martínez Valdebenito, Constanza; Acosta-Jamett, Gerardo; Abello, Rayitray; Jiang, Ju; Richards, Allen L.; Abarca Villaseca, Katia; Weitzel, ThomasAbstract Candidatus 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 Orientia DNA in 24.8% of rodents, belonging to five of seven captured species. Orientia-infection rates showed geographical variations, but were not influenced by rodent species, sex, age, and mite infestation. Phylogenetic analysis showed that Orientia sequences from trombiculid mites (Proschoengastia eloisae) 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 Orientia-infected rodents can also serve as reservoir of Orientia in Chile. Graphical Abstract
- ItemIdentification of trombiculid mites (Acari: Trombiculidae) on rodents from Chiloe Island and molecular evidence of infection with Orientia species(2020) Acosta-Jamett, Gerardo; Martinez-Valdebenito, Constanza; Beltrami, Esperanza; Carolina Silva-de La Fuente, Maria; Jiang, Ju; Richards, Allen L.; Weitzel, Thomas; Abarca, KatiaBackground
- ItemImported scrub typhus: first case in South America and review of the literature(2018) Weitzel, Thomas; Martínez Valdebenito, Constanza Pamela; Abarca Villaseca, Katia; Aylwin, Mabel; Jiang, Ju; Munita, Jose M.; Thompson, Luis; Richards, Allen L.Abstract Background Scrub typhus is a neglected vector-borne zoonosis causing life-threatening illnesses, endemic in the Asian-Pacific region and, as recently discovered, in southern Chile. Scrub typhus is rarely reported in travelers, most probably due to the lack of clinical experience and diagnostic tests in non-endemic countries. We report the first case of imported scrub typhus in South America. Case presentation A 62-year-old tourist from South Korea presented severely ill with fever, rash, and eschar in Santiago, Chile. Laboratory exams showed thrombocytopenia and elevated inflammation parameters, hepatic enzymes, and LDH. With the clinical suspicion of scrub typhus, empirical treatment with doxycycline was initiated and the patient recovered rapidly and without complications. The diagnosis was confirmed by IgM serology and by real-time PCR, which demonstrated infection with Orientia tsutsugamushi (Kawasaki clade). Conclusions Only due to the emerging clinical experience with endemic South American scrub typhus and the recent implementation of appropriate diagnostic techniques in Chile, were we able to firstly identify and adequately manage a severe case of imported scrub typhus in South America. Physicians attending febrile travelers need to be aware of this rickettsiosis, since it requires prompt treatment with doxycycline to avoid complications.Abstract Background Scrub typhus is a neglected vector-borne zoonosis causing life-threatening illnesses, endemic in the Asian-Pacific region and, as recently discovered, in southern Chile. Scrub typhus is rarely reported in travelers, most probably due to the lack of clinical experience and diagnostic tests in non-endemic countries. We report the first case of imported scrub typhus in South America. Case presentation A 62-year-old tourist from South Korea presented severely ill with fever, rash, and eschar in Santiago, Chile. Laboratory exams showed thrombocytopenia and elevated inflammation parameters, hepatic enzymes, and LDH. With the clinical suspicion of scrub typhus, empirical treatment with doxycycline was initiated and the patient recovered rapidly and without complications. The diagnosis was confirmed by IgM serology and by real-time PCR, which demonstrated infection with Orientia tsutsugamushi (Kawasaki clade). Conclusions Only due to the emerging clinical experience with endemic South American scrub typhus and the recent implementation of appropriate diagnostic techniques in Chile, were we able to firstly identify and adequately manage a severe case of imported scrub typhus in South America. Physicians attending febrile travelers need to be aware of this rickettsiosis, since it requires prompt treatment with doxycycline to avoid complications.
- ItemScrub Typhus in Continental Chile, 2016-2018(2019) Weitzel, Thomas; Martinez-Valdebenito, Constanza; Acosta-Jamett, Gerardo; Jiang, Ju; Richards, Allen L.; Abarca, KatiaEndemic scrub typhus was recently detected on Chiloe Island in southern Chile. We report a series of cases, acquired over a wide geographical range in continental Chile during 2016-2018, demonstrating that this emerging rickettsial infection is also found on the mainland of South America.