Browsing by Author "Weitzel, Thomas"

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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; López, Javier; Acosta-Jamett, Gerardo; Edouard, Sophie; Parola, Philippe; Abarca Villaseca, Katia
    Abstract Background Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile. Methods A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA). Results A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population. Conclusion Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.Abstract Background Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile. Methods A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA). Results A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population. Conclusion Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.Abstract Background Coxiella burnetii is an important zoonotic pathogen of global distribution. Still, in most parts of South America including Chile, systematic epidemiological data are lacking. The presented study aims to determine the seroprevalence of Coxiella burnetii antibodies in healthy adults of four different regions in Chile. Methods A cross-sectional study was performed, which included healthy adults living in rural and urban areas of four cities located in different regions in northern, central, and southern Chile. In urban sectors, households were chosen by double stratified random sampling, while in rural areas convenience sampling was performed. Serum specimens were taken and screened for the presence of IgG antibodies against C. burnetii phase II antigen using a commercial ELISA kit. Positive and indeterminate results were confirmed by a reference laboratory using indirect immunofluorescence assay (IFA). Results A total of 1112 individuals were included. Of those, 8 were positive by ELISA, but only one sample was confirmed using IFA. Statistical analysis for population freedom from disease revealed a high probability that C. burnetii was absent in our study population. Conclusion Our work provides the first epidemiological data on human Q fever in Chile indicating either a very low endemicity or the absence of this pathogen in the studied areas.
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    Canine 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
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    Catheter-associated bloodstream infection caused by Leifsonia aquatica in a haemodialysis patient: a case report
    (SOC GENERAL MICROBIOLOGY, 2012) Porte, Lorena; Soto, Andres; Andrighetti, Daniela; Dabanch, Jeannette; Braun, Stephanie; Saldivia, Alejandra; Carlos Flores, Juan; Wozniak, Aniela; Garcia, Patricia; Weitzel, Thomas
    Leifsonia aquatica is an aquatic coryneform rod that is capable of forming biofilms in environmental water sources. It has rarely been associated with human infections and its pathogenicity and clinical significance are uncertain. We describe a case of catheter-related bloodstream infection in a haemodialysis patient. The isolate grew on conventional media as a yellow-pigmented colony, but identification required molecular methods. Although the strain displayed reduced sensitivity to vancomycin, the clinical outcome was favourable after catheter removal and intravenous treatment with this antibiotic. Our report gives further evidence of the capability of this aquatic bacterium to cause human infection.
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    Chikungunya, enfermedad emergente en América Latina. Descripción de los primeros casos en Chile
    (2018) Perret Pérez, Cecilia; Vizcaya Altamirano, María Cecilia; Weitzel, Thomas; Rosas, Reinaldo; Dabanch, Jeannette; Martínez, Constanza
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    Cluster of imported vivax malaria in travelers returning from Peru
    (2015) Weitzel, Thomas; Labarca L., Jaime; Cortes, Claudia P.; Rosas, Reinaldo; Balcells Marty, María Elvira; Perret Pérez, Cecilia
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    Geographical distribution and phylogenetic analysis of rhipicephalus sanguineus sensu lato in northern and central Chile
    (2018) Díaz Acevedo, Fabián Esteban; Martínez Valdebenito, Constanza; López, Javier; Weitzel, Thomas; Abarca Villaseca, Katia
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    Imported 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.
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    Performance of the VITEK MS System for the Identification of Filamentous Fungi in a Routine Microbiological Laboratory in Chile
    (2024) Porte, Lorena; Cruz, Rodrigo; Pérez, Inia; Varela, Carmen; Díaz, Cristina; García Cañete, Patricia; Legarraga, Paulette; Valdivieso, Francisca; Weitzel, Thomas
    Background: Filamentous fungi are an emergent cause of severe infections in immunocompromised patients. Timely and accurate identification is crucial to initiate appropriate therapy. Traditional identification methods are time-consuming, labor-intensive, and operator-dependent. Ma-trix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry is a rapid and easy-to-perform identification method. This study evaluates the effectiveness of a commercial MALDI-TOF MS platform to identify filamentous fungi in a routine laboratory. Material and Methods: We included 67 fungal isolates from 35 species/species complexes within 15 genera, confirmed in mycology reference laboratories. 33 were from clinical samples and 34 from strain collections. The study used the VITEK MS system (v3.2.0 database), after sample extraction by VITEK MS Mould Kit. Results were classified into categories: ‘correct species’, ‘correct species complex’, ‘correct genus’, ‘incorrect identification’, and ‘no identification’. We also evaluated the practicality of the kit. Results: VITEK MS correctly identified 91.0% of isolates (58.2% to species, 29.9% to species complex, and 1.5% to genus level). In 82%, the result matched the species/species complex identified by reference methods. No misidentifications were observed. The kit was rapid and easy to use. Conclusion: The VITEK MS system showed a high capability to accurately identify filamentous fungi in a routine laboratory.
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    Prevalence and Risk Factors for Echinococcal Infection in a Rural Area of Northern Chile : A Household-Based Cross-Sectional Study
    (2014) Acosta Jamett, Gerardo; Weitzel, Thomas; Boufana, Belgees; Adones, Claudia; Bahamonde, Andrea; Abarca Villaseca, Katia; Craig, Philip S.; Reiter-Owona, Ingrid
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    Recomendaciones para viajeros chilenos a la Copa Mundial de la FIFA 2014 en Brasil
    (2014) Perret Pérez, Cecilia; Weitzel, Thomas
    Este artículo proporciona una serie de precauciones a observar y vacunas recomendadas para viajeros chilenos que asistirán a la Copa Mundial de Fútbol 2014 en Brasil. Su propósito es ayudar a los médicos a preparar a los visitantes a este masivo evento y resume las recomendaciones útiles para evitar enfermedades infecciosas, teniendo en consideración las circunstancias y disponibilidad en Chile.
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    Yellow fever vaccination for Chilean tourists visiting Brazil. Practical considerations
    (SOC CHILENA INFECTOLOGIA, 2018) Weitzel, Thomas; Perret, Cecilia; Valdivieso, Francisca; Abarca, Katia; Vial, Pablo
    Due to the recent yellow fever outbreak affecting the costal region of Brazil, including main touristic destinations, there is a high demand of yellow fever vaccination. This publication addresses the most relevant practical issues regarding this vaccine for tourists visiting Brazil and aims to serve as a guideline for non-expert physicians in Chile and elsewhere.