Development and Optimization of a Multiplex Real-Time RT-PCR to Detect SARS-CoV-2 in Human Samples.

PCR and its variants (RT-PCR and qRT-PCR) are valuable and innovative molecular techniques for studying nucleic acids. qPCR has proven to be highly sensitive, efficient, and reproducible, generating reliable results that are easy to analyze. During the COVID-19 pandemic, qPCR became the gold standard technique for detecting the SARS-CoV-2 virus that allowed to confirm the infection event, and those asymptomatic ones, and thus save millions of lives. In-house multiplex qPCR tests were developed worldwide to detect different viral targets and ensure results, follow the infections, and favor the containment of a pandemic. Here, we present the detailed fundamentals of the qPCR technique based on fluorogenic probes and processes to develop and optimize a successful multiplex RT-qPCR test for detecting SARS-CoV-2 that could be used to diagnose COVID-19 accurately.

Seroprevalence, infection, and personal protective equipment use among Colombian healthcare workers during the COVID-19 pandemic.

Introduction: Healthcare workers (HCWs) are at the forefront of the COVID-19 response and frequently come into close contact with patients and their virus-contaminated body fluids. Recent studies have identified differential risks of infection and the use of personal protective equipment (PPE) among HCWs. However, available data might be interpreted with caution because of differences in the national health systems, local implementation issues, and adherence limitations to guidelines. A comprehensive description of infection, exposure at work, and biosafety habits during the COVID-19 pandemic has not been conducted among the HCW groups in Latin American populations. Objective: To describe SARS-CoV-2 seroprevalence, infections, and extent of PPE use during the COVID-19 pandemic among HCWs at three different times, including dental practitioners (DP), nursing assistants (NA), physicians (P), and respiratory therapists (RT), from Bogotá, Colombia. Methods: After IRB approval, this cross-sectional study included 307 HCWs. Participants provided nasopharyngeal swabs and blood samples to detect viral RNA (RT-qPCR) and IgM/IgG anti-SARS-CoV-2 (ELFA-ELISA) at baseline (BL) and two follow-ups. Infection prevalence was defined as the number of positive-tested participants (RT-qPCR and/or IgM). Data on clinical status and biosafety habits were collected each time. Results: Differential infection prevalence was found among HCWs through the study timeline (BL: RT-qPCR = 2.6%, IgM = 1.6%; follow-up 1 (45 days after BL): RT-qPCR = 4.5%, IgM = 3.9%; follow-up 2 (60 days after BL): RT-qPCR = 3.58%, IgM = 1.3%. Dental practitioners showed a higher infection frequency in BL and follow-up 1. IgG-positive tested HCWs percentage progressively increased from BL to follow-ups among the whole sample while index values decreased. Limitations in N95 availability and a high perception of occupational risk were reported. Conclusion: A low prevalence of active SARS-CoV-2 infections among HCWs groups was found. Over time, there was an increase in participants showing IgG antibodies, although the levels of these antibodies in the blood decreased. Additionally, HCWs reported limitations in the availability of PPE as well as a variation in their safety practices.

A Comparison of Lymphoid and Myeloid Cells Derived from Human Hematopoietic Stem Cells Xenografted into NOD-Derived Mouse Strains.

Humanized mice are an invaluable tool for investigating human diseases such as cancer, infectious diseases, and graft-versus-host disease (GvHD). However, it is crucial to understand the strengths and limitations of humanized mice and select the most appropriate model. In this study, we describe the development of the human lymphoid and myeloid lineages using a flow cytometric analysis in four humanized mouse models derived from NOD mice xenotransplanted with CD34+ fetal cord blood from a single donor. Our results showed that all murine strains sustained human immune cells within a proinflammatory environment induced by GvHD. However, the Hu-SGM3 model consistently generated higher numbers of human T cells, monocytes, dendritic cells, mast cells, and megakaryocytes, and a low number of circulating platelets showing an activated profile when compared with the other murine strains. The hu-NOG-EXL model had a similar cell development profile but a higher number of circulating platelets with an inactivated state, and the hu-NSG and hu-NCG developed low frequencies of immune cells compared with the other models. Interestingly, only the hu-SGM3 and hu-EXL models developed mast cells. In conclusion, our findings highlight the importance of selecting the appropriate humanized mouse model for specific research questions, considering the strengths and limitations of each model and the immune cell populations of interest.

Endothelial Dysfunction, HMGB1, and Dengue: An Enigma to Solve.

Dengue is a viral infection caused by dengue virus (DENV), which has a significant impact on public health worldwide. Although most infections are asymptomatic, a series of severe clinical manifestations such as hemorrhage and plasma leakage can occur during the severe presentation of the disease. This suggests that the virus or host immune response may affect the protective function of endothelial barriers, ultimately being considered the most relevant event in severe and fatal dengue pathogenesis. The mechanisms that induce these alterations are diverse. It has been suggested that the high mobility group box 1 protein (HMGB1) may be involved in endothelial dysfunction. This non-histone nuclear protein has different immunomodulatory activities and belongs to the alarmin group. High concentrations of HMGB1 have been detected in patients with several infectious diseases, including dengue, and it could be considered as a biomarker for the early diagnosis of dengue and a predictor of complications of the disease. This review summarizes the main features of dengue infection and describes the known causes associated with endothelial dysfunction, highlighting the involvement and possible relationship between HMGB1 and DENV.

Humanized Mice in Dengue Research: A Comparison with Other Mouse Models.

Dengue virus (DENV) is an arbovirus of the Flaviviridae family and is an enveloped virion containing a positive sense single-stranded RNA genome. DENV causes dengue fever (DF) which is characterized by an undifferentiated syndrome accompanied by fever, fatigue, dizziness, muscle aches, and in severe cases, patients can deteriorate and develop life-threatening vascular leakage, bleeding, and multi-organ failure. DF is the most prevalent mosquito-borne disease affecting more than 390 million people per year with a mortality rate close to 1% in the general population but especially high among children. There is no specific treatment and there is only one licensed vaccine with restricted application. Clinical and experimental evidence advocate the role of the humoral and T-cell responses in protection against DF, as well as a role in the disease pathogenesis. A lot of pro-inflammatory factors induced during the infectious process are involved in increased severity in dengue disease. The advances in DF research have been hampered by the lack of an animal model that recreates all the characteristics of this disease. Experiments in nonhuman primates (NHP) had failed to reproduce all clinical signs of DF disease and during the past decade, humanized mouse models have demonstrated several benefits in the study of viral diseases affecting humans. In DENV studies, some of these models recapitulate specific signs of disease that are useful to test drugs or vaccine candidates. However, there is still a need for a more complete model mimicking the full spectrum of DENV. This review focuses on describing the advances in this area of research.

Prevalence of dengue antibodies in healthy children and adults in different Colombian endemic areas.

OBJECTIVES: Colombia is a dengue hyperendemic country; however, the prevalence of antibodies against dengue in the general population including the inhabitants of rural areas is unknown. This study aimed to determine the prevalence of dengue IgM and IgG antibodies in healthy children and adults in urban and rural areas of seven different endemic regions in Colombia between 2013 and 2015. DESIGN OR METHOD: Blood samples from healthy volunteers (1,318) were processed by serology (by indirect IgG and capture IgM and IgG ELISA) and molecular tests to detect viral RNA and circulating serotypes. RESULTS: The seroprevalence of IgG for dengue were 85% in children and over 90% for adults. In addition to the high IgM positive rate (14.9%) and secondary recent infection marker rate (capture IgG, 16%), 8.4% of the healthy volunteers were positive for dengue virus (DENV) RNA. CONCLUSION: This study confirmed the broad and permanent circulation of DENV in Colombia and the high rates of infection and reinfection suffered by its inhabitants. This information can be used by the health authorities to strengthen vector control and vaccine policies and review the algorithms of diagnosis and disease management in children and adults.

Factors Associated with Dengue Virus Infection and Reinfection in Asymptomatic Children in Two Colombian Municipalities.

Dengue is the most important arbovirosis in the world. In this study, we assessed the knowledge, attitudes, and practices (KAP) regarding dengue in parents from two small Colombian municipalities in the Cundinamarca Province. Parents and their healthy children from 4 to 14 years of age were included in some public elementary schools. After a medical examination, blood samples were taken for diagnosis of dengue using enzyme-linked immunosorbent assays (capture immunoglobulin M and capture immunoglobulin G [IgG], indirect IgG and detection non-structural viral protein 1) and detection of viral RNA by reverse transcription polymerase chain reaction. In addition, a KAP survey was applied to the children's parents or tutors. The indirect IgG test determined that of the 347 examined children, 87.9% had a previous infection with the dengue virus (DENV), 12.7% of them were positive for viral RNA (asymptomatic infection), and 32.0% presented reinfections. Risk factors evaluation showed that children aged 8 years and older living in the municipalities for more than 7 years were more likely to be infected or reinfected by DENV. In the same way, poor nutrition, lack of water supply, sewer service, or waste disposal services could raise the likelihood of dengue infections. The surveys indicated that parents have unhealthy practices and a low knowledge about the transmission of the disease, which could result in an increase of mosquito breeding sites, allowing sustained dengue transmission.

Dengue virus detection in Aedes aegypti larvae and pupae collected in rural areas of Anapoima, Cundinamarca, Colombia.

INTRODUCTION: There is a high incidence and prevalence of dengue in the department of Cundinamarca, and recently Aedes aegypti, the main vector of dengue virus (DENV), was detected in some of its rural areas. OBJECTIVE: To evaluate viral transovarial transmission in larvae and pupae collected in rural areas of the municipality of Anapoima, Cundinamarca. MATERIALS AND METHODS: Live larvae and pupae were collected from 53 homes and later they were taken to the laboratory in Anapoima, where they were classified, pooled and frozen. In Bogotá, they were homogenized, RNA was extracted with Trizol™, and RT-PCR and conventional PCR were performed. The amplified products were analyzed on 2% agarose gels. RESULTS: In 54.7% of the houses we found A. aegypti in immature stages, and DENV-1 was the most frequent serotype. However, the simultaneous presence of DENV 1 and 2, DENV 1 and 3, DENV 1 and 4, and DENV 1, 2 and 3 serotypes was detected in some pools. CONCLUSION: The results confirmed the natural vertical transmission of the virus in the rural area under study. These findings confirmed the vector capacity of A. aegypti, and partly explains the persistence of the virus in the region and the possibility of transmission by the vector during adulthood without having ingested infected blood. This situation increases the risk of DENV infection in Colombia and the need for prevention and control programs in all areas where the mosquito is present.

Diagnóstico diferencial de dengue y chikungunya en pacientes pediátricos / Dengue and Chikungunya differential diagnosis in pediatric patients

Introducción. Las infecciones por el virus del dengue y del chikungunya presentan síntomas clínicos similares, lo cual dificulta el diagnóstico clínico. Además, son transmitidas por los mismos vectores, por lo que en una región puede haber circulación e infección simultánea con los dos virus. Los resultados de cada enfermedad, no obstante, son diferentes: la fiebre del chikungunya rara vez es fatal, pero puede dejar secuelas de tipo articular y neurológico, en tanto que el dengue es potencialmente fatal. De ahí la importancia de un diagnóstico preciso y oportuno. Objetivo. Comparar el diagnóstico presuntivo basado en los hallazgos clínicos con el diagnóstico diferencial hecho mediante pruebas de laboratorio. Materiales y métodos. Se utilizaron pruebas virológicas y serológicas específicas para dengue y chikungunya en ocho muestras de sangre de pacientes pediátricos con síndrome febril. Se empleó la reacción en cadena de la polimerasa con transcriptasa inversa para detectar los virus del dengue y del chikungunya y el método de ELISA basado en la captura de IgM para confirmar los casos de dengue. Resultados. Con base en los hallazgos clínicos, dos pacientes se clasificaron como casos probables de dengue o chikungunya, dos como casos probables de chikungunya y en cuatro no hubo diagnóstico presuntivo de infección viral. Las pruebas de laboratorio confirmaron la infección por el virus del dengue en dos pacientes, por el virus del chikungunya en otros dos e infección simultánea de dengue y chikungunya en los cuatro restantes. Conclusión. Los hallazgos clínicos no fueron suficientes para hacer un diagnóstico en pacientes pediátricos con síndrome febril, por lo cual se requirieron pruebas específicas de laboratorio para establecer con precisión el agente etiológico causante de la enfermedad.

Introduction: Dengue and Chikungunya infections have similar clinical symptoms, which makes their clinical diagnosis complex. Moreover, both are transmitted by the same mosquito vectors, which results in virus co-circulation and co-infection. However, the outcome of these diseases differs: Chikungunya fever is rarely fatal but can have permanent and severe rheumatic and neurological sequelae, whereas dengue disease is potentially fatal. Thus, accurate diagnosis is critical. Objective: To compare presumptive diagnoses based on clinical findings with the differential diagnoses based on specific laboratory tests for each virus. Materials and methods: We performed specific virological and serological tests for both dengue and Chikungunya infections on eight acute-phase blood samples collected from pediatric patients with febrile syndrome. We used RT-PCR to detect dengue and Chikungunya virus, and IgM-capture ELISA to confirm infection by dengue virus. Results: Based on clinical findings, two patients were diagnosed as probable cases of dengue or Chikungunya, and two were diagnosed as probable cases of chikungunya. Four had no presumptive diagnosis of viral infection. Laboratory tests confirmed dengue infection in two patients, Chikungunya infection in two patients, and co-infection by the two viruses in the other four patients. Conclusion: Clinical findings were not sufficient to make a diagnosis in pediatric patients with febrile syndrome; specific laboratory tests were required to establish the etiologic agent of the disease.

Alta correlación en la detección de anticuerpos y antígenos de virus del dengue en muestras de suero y plasma / High correlation in dengue antibodies and antigen detection using serum or plasma samples

Introducción. El diagnóstico adecuado de dengue por laboratorio es importante para la atención, así como para el control de brotes y epidemias. Hasta el momento, las pruebas ELISA para diagnóstico serológico de la infección se encuentran validadas en muestras de suero; sin embargo, en algunas ocasiones la cantidad o calidad de la muestra es inadecuada, o solo se tiene acceso a sangre anticoagulada tomada para el análisis de los parámetros hematológicos en el hemograma. Objetivo. Evaluar el desempeño de cuatro pruebas ELISA en muestras de suero y plasma de casos sospechosos de dengue. Materiales y métodos. Se procesaron 42 muestras -21 de suero y 21 de plasma- por las técnicas de ELISA de captura para IgM, ELISA de captura para IgG, ELISA indirecta para IgG y ELISA para la detección del antígeno viral NS1. Resultados. El porcentaje de muestras positivas encontrado fue IgM 33.3%, IgG Captura 33.3%, IgG Indirecta 90.5%, NS1 23.8%. El 42.9% de las muestras fueron positivas por RT-PCR (n=9). Todas las pruebas se comportaron igual tanto en sueros como plasmas (coeficiente Kappa 1.0). Conclusión. Los resultados obtenidos muestran una alta concordancia entre las mediciones realizadas en suero y en plasma, lo cual sugiere que la muestra de plasma puede utilizarse para el diagnóstico y la confirmación de los casos de dengue.

Introduction. Appropriate dengue laboratory diagnosis is an important tool to manage the disease, as well to control possible outbreaks. Currently, ELISA dengue serological tests are validated to use with serum, however sometimes samples quality or quantity is inappropriate or there is only availability of anti-coagulated blood samples which have been used in total blood tests -haemogram-. Objective. To assess the performance of four dengue ELISA tests in serum or plasma samples obtained from presumptive dengue cases. Methodology. Forty two samples, 21 of serum and plasma each, were processed to dengue Capture IgM ultramicro-ELISA, Capture IgG ELISA, Indirect IgG ELISA and NS1 antigen ELISA. Nine out of 21 patients were diagnosed as dengue cases following the diagnostic algorithm. Results. The percentage of positive samples found was Capture IgM 33.3%, Capture IgG 33.3%, Indirect IgG 90.5% and NS1 dengue antigen 23.8%. Comparing the results between all ELISA tests it can be said that they had similar performances both in serum and plasma, the Kappa coefficient obtained was 1.0. Conclusions. These results show a high concordance between the measurements carried out in serum and plasma, which leads to suggest the latter may be used as a tool in the diagnosis and confirmation of dengue cases.

Dengue and Chikungunya differential diagnosis in pediatric patients.

INTRODUCTION: Dengue and Chikungunya infections have similar clinical symptoms, which makes their clinical diagnosis complex. Moreover, both are transmitted by the same mosquito vectors, which results in virus co-circulation and co-infection. However, the outcome of these diseases differs: Chikungunya fever is rarely fatal but can have permanent and severe rheumatic and neurological sequelae, whereas dengue disease is potentially fatal. Thus, accurate diagnosis is critical.  OBJECTIVE: To compare presumptive diagnoses based on clinical findings with the differential diagnoses based on specific laboratory tests for each virus.  MATERIALS AND METHODS: We performed specific virological and serological tests for both dengue and Chikungunya infections on eight acute-phase blood samples collected from pediatric patients with febrile syndrome. We used RT-PCR to detect dengue and Chikungunya virus, and IgM-capture ELISA to confirm infection by dengue virus.  RESULTS: Based on clinical findings, two patients were diagnosed as probable cases of dengue or Chikungunya, and two were diagnosed as probable cases of chikungunya. Four had no presumptive diagnosis of viral infection. Laboratory tests confirmed dengue infection in two patients, Chikungunya infection in two patients, and co-infection by the two viruses in the other four patients.  CONCLUSION: Clinical findings were not sufficient to make a diagnosis in pediatric patients with febrile syndrome; specific laboratory tests were required to establish the etiologic agent of the disease.

Dengue disease diagnosis: A puzzle to be solved / El diagnóstico en dengue: un rompecabezas a resolver

Dengue is an infection caused by dengue virus and is the most important arthropod transmitted viral disease in the world, causing near 100 million cases and 50 000 fatalities each year. Health authorities believe that these numbers will grow in coming years. In Colombia, almost 600 municipalities are in regions with Aedes aegypti circulation, and the presence of four dengue serotypes has been demonstrated. Despite the increasing knowledge about disease pathogenesis and the dengue virus, some technical or scientific difficulties with diagnosing dengue remain, negatively affecting both public health surveillance and the appropriate attention to patients in health settings and hospitals. This paper reviews the principles and developments of the current diagnostic techniques for dengue, pointing out the difficulties with making accurate dengue diagnoses and case confirmations in public health and specialized laboratories. The principles and limitations of MAC-ELISA, IgG serology, viral NS1 detection and viral isolation by cell culture are presented. In addition, the review of immunochromatography techniques (rapid diagnostic tests) that have been put forward to help the point-of-care diagnosis is proposed. This paper is intended to bring forward some points of view about the issues related to dengue diagnosis and contribute to improve the discussion surrounding the strategies and techniques needed for reducing the impact of the disease and favoring its control.

La infección por el virus de dengue es la enfermedad viral transmitida por insectos más importante del mundo que genera grandes gastos a los sistemas de salud. En Colombia, en más de 600 municipios está presente el mosquito vector y se ha detectado la circulación de los cuatro serotipos del virus, haciendo previsible que la incidencia y prevalencia sigan aumentando. Aunque se han hecho grandes avances y desarrollos para entender la enfermedad, existen vacíos científicos y técnicos que dificultan su correcto diagnóstico y que debilitan tanto la vigilancia en salud pública como la correcta atención en las instituciones prestadoras de salud. En este documento se revisan los principios e interpretaciones de las herramientas de laboratorio disponibles para el diagnóstico de dengue, haciendo énfasis en las dificultades existentes para la correcta definición de los casos desde el laboratorio general y especializado. Se explican los fundamentos y limitaciones de las técnicas de ELISA de captura de anticuerpos IgM, serología para IgG, detección del antígeno viral NS1, aislamiento viral en cultivos celulares y las pruebas más recientes basadas en la inmunocromatografía -pruebas rápidas-. La revisión se propone, además de aportar a la discusión sobre las dificultades para el diagnóstico en dengue, ofrecer una idea actualizada sobre cómo abordar el diagnóstico tanto en los laboratorios de salud pública como en los laboratorios especializados y contribuir así a mejorar los estándares de atención de los pacientes, reducir el impacto de la enfermedad y favorecer su control.

Evaluación de la utilidad de la prueba rápida de casete por inmunocromatografía para el diagnóstico de dengue en una región endémica colombiana / Evaluation of PANBIO rapid immunochromatographic cassette for dengue diagnosis in a Colombian endemic area

Introducción. Las pruebas convencionales para el diagnóstico serológico de dengue son de reducida utilidad para el clínico durante los primeros días de la enfermedad, debido a su baja sensibilidad, su relativa complejidad técnica y el tiempo necesario para su realización. Objetivo. Determinar la reproducibilidad, exactitud y utilidad clínica de la prueba rápida en casete (PANBIO) para el diagnóstico de dengue en muestras de pacientes agudos o convalescientes. Materiales y métodos. La prueba de inmunocromatografía se evaluó en pacientes de 5 o más años de edad, con síndrome febril agudo, captados en el área metropolitana de Bucaramanga entre abril y agosto de 2003. Se utilizó suero de la fase aguda y de la convalecencia de 67 casos de dengue diagnosticados mediante pruebas de IgM pareadas (MAC-ELISA), y de 33 con síndrome febril agudo de etiología diferente a dengue. Resultados. La prueba mostró buena reproducibilidad entre observadores (kappa=0,84). En la convalecencia, la prueba para la IgM tuvo una sensibilidad de 76,1%, especificidad de 75,8%, un valor diagnóstico positivo de 86,4%, un valor diagnóstico negativo de 61%, una razón de verosimilitud positiva de 3,14 y una negativa de 0,32. En la fase aguda, los valores encontrados fueron 52,2%, 84,8%, 87,5%, 46,7%, 3,45 y 0,56, respectivamente. Conclusiones. La prueba de casete para el diagnóstico rápido de dengue muestra una buena reproducibilidad y unas características operativas aceptables. Por esta razón, podría recomendarse como ayuda diagnóstica en áreas endémicas de dengue.

Introduction. Traditional tests for dengue diagnosis are not useful during the first days of disease onset, because they require time and complex techniques or because they have low sensitivity. Objective. The reliability and precisison was determined for the rapid test in cassette (PANBIO) for dengue diagnosis in acute and convalescent serum samples. Materials and methods. The immunochromatographic test was evaluated in samples from patients older than 5 years with acute febrile syndrome. The patients came from the metropolitan area of Bucaramanga during April and August of 2003. Acute and convalescent serum came from 67 dengue cases, diagnosed by viral isolation or IgM paired tests (modified MAC-ELISA), and from 33 patients with acute febrile syndrome (not dengue) that served as controls. Results. Reliability was good (kappa=0.84). In the convalescent serum, the test showed sensitivity of 76.1%, specificity of 75.8%, positive predictive value of 86.4% and negative predictive value of 61.0%, positive likelihood ratio 3.14 and negative likelihood ratio 0.32. In the acute phase, the values were 52.2%, 84.8%, 87.5%, 46.7%, 3.45 and 0.56, respectively. Conclusions. Rapid immunochromatographic test for dengue diagnosis shows good reproducibility and specificity, with an acceptable sensitivity. Therefore, this rapid test is recommended as diagnostic tool in endemic areas.

[Evaluation of PANBIO rapid immunochromatographic cassette for dengue diagnosis in a Colombian endemic area]. / Evaluación de la utilidad de la prueba rápida de casete por inmunocromatografía para el diagnóstico de dengue en una región endémica colombiana.

INTRODUCTION: Traditional tests for dengue diagnosis are not useful during the first days of disease onset, because they require time and complex techniques or because they have low sensitivity. Objective. The reliability and precision was determined for the rapid test in cassette (PANBIO) for dengue diagnosis in acute and convalescent serum samples. MATERIALS AND METHODS: The immunochromatographic test was evaluated in samples from patients older than 5 years with acute febrile syndrome. The patients came from the metropolitan area of Bucaramanga during April and August of 2003. Acute and convalescent serum came from 67 dengue cases, diagnosed by viral isolation or IgM paired tests (modified MAC-ELISA), and from 33 patients with acute febrile syndrome (not dengue) that served as controls. RESULTS: Reliability was good (kappa=0.84). In the convalescent serum, the test showed sensitivity of 76.1%, specificity of 75.8%, positive predictive value of 86.4% and negative predictive value of 61.0%, positive likelihood ratio 3.14 and negative likelihood ratio 0.32. In the acute phase, the values were 52.2%, 84.8%, 87.5%, 46.7%, 3.45 and 0.56, respectively. CONCLUSIONS: Rapid immunochromatographic test for dengue diagnosis shows good reproducibility and specificity, with an acceptable sensitivity. Therefore, this rapid test is recommended as diagnostic tool in endemic areas.

[Association between glutathione peroxidase levels and clinical manifestations of dengue]. / Correlación entre los niveles de glutatión peroxidasa, un marcador de estrés oxidativo, y la presentación clínica del dengue.

BACKGROUND: Glutathione peroxidase (GP) can be used as a marker of oxidative stress in infectious diseases. AIM: To evaluate the association between the levels of glutathione peroxidase (GP) and the manifestations and complications of dengue. PATIENTS AND METHODS: Between April 2003 and December 2004, 161 patients with dengue were prospectively evaluated. In the first evaluation, within 48 and 96 hours of disease onset, a plasma sample was obtained to measure the GP levels. The association between GP levels, clinical manifestations and complications was evaluated during the follow up. RESULTS: Mean GP values were 1198 U/L (95% confidence interval 1089-1306). Values greater than 1200 U/L were associated with headache, arthralgias and increased heart rate. There was a negative association between GP levels and serum triglycerides. During follow up, patients with GP >1200 U/L had a higher frequency of spontaneous hemorrhages. In a logistic regression analysis arthralgias, fever and increased heart rate, were independently associated with levels >1200 U/L. CONCLUSIONS: GP levels was associated to some of the manifestations of dengue. This finding suggests that the intensity of oxidative stress can influence the clinical presentation of dengue.

Correlación entre los niveles de glutatión peroxidasa, un marcador de estrés oxidativo, y la presentación clínica del dengue / Association between glutathione peroxidase levels and clinical manifestations of dengue

Background: Glutathione peroxidase (GP) can be used as a marker of oxidative stress in infectious diseases. Aim: To evaluate the association between the levels of glutathione peroxidase (GP) and the manifestations and complications of dengue. Patients and Methods: Between April 2003 and December 2004, 161 patients with dengue were prospectively evaluated. In the first evaluation, within 48 and 96 hours of disease onset, a plasma sample was obtained to measure the GP levels. The association between GP levels, clinical manifestations and complications was evaluated during the follow up. Results: Mean GP values were 1198 U/L (95 percent confidence interval 1089-1306). Values greater than 1200 U/L were associated with headache, arthralgias and increased heart rate. There was a negative association between GP levels and serum triglycerides. During follow up, patients with GP >1200 U/L had a higher frequency of spontaneous hemorrhages. In a logistic regression analysis arthralgias, fever and increased heart rate, were independently associated with levels >1200 U/L. Conclusions: GP levels was associated to some of the manifestations of dengue. This finding suggests that the intensity of oxidative stress can influence the clinical presentation of dengue.