Browsing by Author "Rosas, Reinaldo"
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Item An. gambiae gSG6-P1 evaluation as a proxy for human-vector contact in the Americas: a pilot study.(Biomed Central Ltd., 2015) Londono, Berlin; Drame, Papa; Weitzel, Thomas; Rosas, Reinaldo; Gripping, Crystal; Cárdenas, Jenny; Alvares, Marcela; Wesson, Dawn; Poinsignon, Anne; Remoue, Franck; Colpitts, TonyaBACKGROUND: During blood meal, the female mosquito injects saliva able to elicit an immune response in the vertebrate. This immune response has been proven to reflect the intensity of exposure to mosquito bites and risk of infection for vector transmitted pathogens such as malaria. The peptide gSG6-P1 of An. gambiae saliva has been demonstrated to be antigenic and highly specific to Anopheles as a genus. However, the applicability of gSG6-P1 to measure exposure to different Anopheles species endemic in the Americas has yet to be evaluated. The purpose of this pilot study was to test whether human participants living in American countries present antibodies able to recognize the gSG6-P1, and whether these antibodies are useful as a proxy for mosquito bite exposure and malaria risk. METHODS: We tested human serum samples from Colombia, Chile, and the United States for the presence of IgG antibodies against gSG6-P1 by ELISA. Antibody concentrations were expressed as delta optical density (ΔOD) of each sera tested in duplicates. The difference in the antibody concentrations between groups was tested using the nonparametric Mann Whitney test (independent groups) and the nonparametric Wilcoxon matched-pairs signed rank test (dependent groups). All differences were considered significant with a P < 0.05. RESULTS: We found that the concentration of gSG6-P1 antibodies was significantly correlated with malaria infection status and mosquito bite exposure history. People with clinical malaria presented significantly higher concentrations of IgG anti-gSG6-P1 antibodies than healthy controls. Additionally, a significant raise in antibody concentrations was observed in subjects returning from malaria endemic areas. CONCLUSION: Our data shows that gSG6-P1 is a suitable candidate for the evaluation of exposure to Anopheles mosquito bites, risk of malaria transmission, and effectiveness of protection measures against mosquito bites in the Americas.Item Chikungunya, enfermedad emergente en América Latina. Descripción de los primeros casos en Chile(2018) Perret, Cecilia; Vizcaya, Cecilia; Weitzel, Thomas; Rosas, Reinaldo; Dabanch, Jeannette; Martínez, ConstanzaBackground: Chikungunya (CHIK) was introduced in The Americas in 2013, spreading rapidly. In 2014, the first imported case was diagnosed in Chile. Aim: To identify patients with clinical suspicion of CHIK and describe their clinical and laboratory characteristics. Patients and Methods: Patients with suspected CHIK were enrolled. All were confirmed by PCR, IgM or IgG CHIK. A structured survey was applied, which included demographic questions, travel characteristics, clinical manifestations, and laboratory results. Results: 21 patients were enrolled and CHIK was confirmed in 16, who were further analyzed; 12 were female (75%), average age 39 years (27-52). The Caribbean and South Americawere the most frequent sites of exposure. In 63%, the initial symptom was arthralgia. Most frequent symptoms were myalgias, malaise (both 100%), fever, and polyarthralgia (both 94%). The median duration of arthralgias was 90 days (3-262); in 53% arthralgias lasted ≥ 3 months. Main joints involved were ankles, hands, and wrists; 87% reported invalidating pain. Arthritis lasted longer in men than in women (p < 0.001). 38% of patients presented lymphopenia and one patient mild thrombocytopenia. Two patients required hospitalization, one with severe headaches, the other with acute pyelonephritis. Conclusions: Chikungunya should be suspected in returning travelers presenting with fever and severe polyarthralgia. Travelers to endemic areas should apply prevention measures to avoid mosquito bites.Item Cluster of imported vivax malaria in travelers returning from Peru.(International Society of Travel Medicine., 2015) Weitzel, Thomas; Labarca, Jaime; Cortés, Claudia; Rosas, Reinaldo; Balcells, Elvira; Perret, CeciliaWe report a cluster of imported vivax malaria in three of five Chilean travelers returning from Peru in March 2015. The cluster highlights the high risk of malaria in the Loreto region in northern Peru, which includes popular destinations for international nature and adventure tourism. According to local surveillance data, Plasmodium vivax is predominating, but Plasmodium falciparum is also present, and the incidence of both species has increased during recent years. Travelers visiting this region should be counseled about the prevention of malaria and the options for chemoprophylaxis.Item Infección por Bartonella henselae: utilidad de las imágenes en el diagnóstico y seguimiento.(Sociedad Chilena de Infectología, 2017) Tapia, Fernanda; Rosas, Reinaldo; Schiappacasse, Giancarlo; Thompson, LuisBartonella henselae infection is a frequent zoonosis from the domestic cat. It is presented with regional lymphadenitis in the majority of cases. Searching and characterization of lymph nodes by diagnostic imaging can be useful in the differential diagnosis approach, with a clear advantage, because it is a noninvasive method. Currently, new diagnostic imaging techniques improves the quality of screening and characterization of adenopathies, such is the case of PET/CT, which allows a better evaluation of hypermetabolic lymph nodes, without considering the individual growth of each lymph node. In this article, three cases of cat scratch diseases serology and their respective imaging findings are reviewed.Item Infecciones respiratorias bacteriémicas por Neisseria meningitidis serogrupo W(Sociedad Chilena de Infectología, 2015) Rosas, Reinaldo; Solar, Sebastián; Durán, Luisa; Noriega, Luis; Thompson, Luis; Marcotti, Alejandra; Pérez, Jorge; Weitzel, ThomasN. meningitidis serogroup W has recently been introduced into Chile. This serogroup has been associated with hypervirulent strains capable of causing outbreaks. Furthermore, there is data suggesting that the spectrum of clinical manifestations varies among different serogroups. Here we describe three cases of community acquired respiratory infections caused by N. meningitidis W, which were diagnosed by blood culture during 2013 in our hospital.Item Is there a risk of filarial infection during long-term missions in Haiti?(Elsevier, 2016) Weitzel, Thomas; Rosas, Reinaldo; Fica, Alberto; Dabanch, Jeannette; Polanco, Myriam; Egaña, Alicia; Triantafilo, Vjera; Pfarr, Kenneth; Hoerauf, Achim; Reiter-Owona, IngridBACKGROUND: Haiti has the highest prevalence of lymphatic filariasis (Wuchereria bancrofti) in the Western Hemisphere. Still, the risk of filarial infection for long-term visitors such as humanitarian aid workers or military personnel is uncertain. The presented study analyzed the exposure to W. bancrofti in Chilean participants of the UN Stabilization Mission in Haiti (MINUSTAH) in 2011. METHODS: Blood samples collected from 531 participants were screened for antifilarial antibodies by IgG ELISA, and, if positive, analyzed by immunofluorescence assay (IFA), IgG4 ELISA, Real-Time PCR, and circulating filarial antigen (CFA) card test. RESULTS: ELISA screening was positive in 10 cases. Seroconversion occurred in only two cases (0.38%) based on ELISA values determined in samples taken before and after deployment. Positive IgG ELISA values could not be confirmed by IFA and IgG4 ELISA. Real-Time PCR and CFA testing did not reveal the presence of filaria. CONCLUSIONS: Our data indicate that in the examined cohort of MINUSTAH participants in 2011, the risk of filarial exposure or infection was low.Item Vulvitis migratoria causada por gnatostomiasis importada(2019) Rosas, Reinaldo; Marcotti, Alejandra; Weitzel, Thomas; Thompson, LuisGnathostomiasis is an emerging disease in non-endemic countries. This zoonotic nematode requires aquatic freshwater environments to complete its life cycle where larvae get encrusted in fishes. Typically, the infection manifests as migratory subcutaneous lesion caused by the larvae trak, which produces an eosinophilic panniculitis. Here we describe a patient who presented a migratory lesion with no response to antimicrobial therapy, a careful travel and food history together with specific laboratory tests led to the correct diagnosis. Gnathostomiasis should be suspected in patients with migratory skin lesions who have consumed raw freshwater fish during travel to endemic countries in South America or A