Browsing by Author "Lopez, Javier"
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Item Absence of convincing evidence of Coxiella burnetii infection in Chile: a cross-sectional serosurvey among healthy adults in four different regions(BMJ Publishing Group, 2016) Weitzel, Thomas; Lopez, Javier; Acosta-Jamett, Gerardo; Edouard, Sophie; Parola, Philippe; Abarca, KatiaBackground: 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.Item Brotes de salmonelosis y el tamaño y rol del Estado en Chile(Sociedad Chilena de Infectología, 2012) Fica, Alberto; Acosta-Jamett, Gerardo; Dabanch, Jeannette; Perret, Cecilia; Torres, Marisa; Lopez, Javier; Jofre, Leonor; Weitzel, Thomas; Comité de Infecciones Emergentes de la Sociedad Chilena de InfectologíaDuring year 2011 two outbreaks of Salmonella infection captured media attention in the Metropolitan Area (MA) in Chile: one of typhoid fever associated to Salmonella serotype Typhi, and the other, of gastroenteritis related to Salmonella serotype Enteritidis, both with decreasing or stable rates in the previous years. The aim of this work is to analyze probable causes of their reemergence. Methods: Several government websites were searched looking for epidemiological data. Results: Typhoid fever rates have declined to current values of 1 case per 100.000 habitants, a decreased associated to improvements in the human development index. The typhoid outbreak was associated to a predominant clone within the MA. The only risk factor identified was consumption of raw vegetables acquired in open fairs, but without identifying a common source. Despite improvements in disease notification and molecular epidemiology capabilities, this outbreak is coincidental with a reduced number of food inspection visits in the MA, probably explained by the limited personnel available for this task. In the case of Salmonella Enteritidis, rates have increased twice since 1998 (5.3 to 10.7 per 100.000 habitants) with an important increase in the number of outbreaks linked to this agent (7 to 31 annual outbreaks) since year 2005. Persistence of this problem is probably associated to the low surveillance of poultry farms made by the Chilean state, to the absence of a cold chain during collection, distribution and selling of eggs, and to the lack of an educational program directed to the population. The recent regulation that bans home-made mayonnaise in restaurant or fast food stores is an important advance that requires further evaluation. Conclusions: The persistence and reemergence of different kind of Salmonellosis in Chile suggests chronic problems on the size and role of the Chilean state regarding food safety.Item Endemic scrub typhus in South America(Massachusetts Medical Society, 2016) Weitzel, Thomas; Dittrich, Sabine; Lopez, Javier; Phuklia, Weerawat; Martinez-Valdebenito, Constanza; Velásquez, Katia; Blacksell, Stuart; Paris, Daniel; Abarca, KatiaScrub typhus is a life-threatening zoonosis caused by Orientia tsutsugamushi organisms that are transmitted by the larvae of trombiculid mites. Endemic scrub typhus was originally thought to be confined to the so called “tsutsugamushi triangle” within the Asia–Pacific region. In 2006, however, two individual cases were detected in the Middle East and South America, which suggested that the pathogen was present farther afield. Here, we report three autochthonous cases of scrub typhus caused by O. tsutsugamushi acquired on Chiloé Island in southern Chile, which suggests the existence of an endemic focus in South America.