Global and cell type-specific immunological hallmarks of severe dengue progression identified via a systems immunology approach.

Severe dengue (SD) is a major cause of morbidity and mortality. To define dengue virus (DENV) target cells and immunological hallmarks of SD progression in children's blood, we integrated two single-cell approaches capturing cellular and viral elements: virus-inclusive single-cell RNA sequencing (viscRNA-Seq 2) and targeted proteomics with secretome analysis and functional assays. Beyond myeloid cells, in natural infection, B cells harbor replicating DENV capable of infecting permissive cells. Alterations in cell type abundance, gene and protein expression and secretion as well as cell-cell communications point towards increased immune cell migration and inflammation in SD progressors. Concurrently, antigen-presenting cells from SD progressors demonstrate intact uptake yet impaired interferon response and antigen processing and presentation signatures, which are partly modulated by DENV. Increased activation, regulation and exhaustion of effector responses and expansion of HLA-DR-expressing adaptive-like NK cells also characterize SD progressors. These findings reveal DENV target cells in human blood and provide insight into SD pathogenesis beyond antibody-mediated enhancement.

Host biomarkers distinguish dengue from leptospirosis in Colombia: a case-control study.

BACKGROUND: Dengue fever and leptospirosis have partially overlapping geographic distributions, similar clinical presentations and potentially life-threatening complications but require different treatments. Distinguishing between these cosmopolitan emerging pathogens represents a diagnostic dilemma of global importance. We hypothesized that perturbations in host biomarkers can differentiate between individuals with dengue fever and leptospirosis during the acute phase of illness. METHODS: We randomly selected subjects from a prospective cohort study of acute febrile illness in Bucaramanga, Colombia and tested 19 serum biomarkers by ELISA in dengue fever (DF, n = 113) compared to subjects with leptospirosis (n = 47). Biomarkers were selected for further analysis if they had good discriminatory ability (area under the ROC curve (AUC) >0.80) and were beyond a reference range (assessed using local healthy controls). RESULTS: Nine biomarkers differed significantly between dengue fever and leptospirosis, with higher levels of Angptl3, IL-18BP, IP-10/CXCL10, Platelet Factor 4, sICAM-1, Factor D, sEng and sKDR in dengue and higher levels of sTie-2 in leptospirosis (p < 0.001 for all comparisons). Two biomarkers, sEng and IL18BP, showed excellent discriminatory ability (AUROC >0.90). When incorporated into multivariable models, sEng and IL18BP improved the diagnostic accuracy of clinical information alone. CONCLUSIONS: These results suggest that host biomarkers may have utility in differentiating between dengue and leptospirosis, clinically similar conditions of different etiology.

Magnitude and kinetics of the human immune cell response associated with severe dengue progression by single-cell proteomics.

Approximately 5 million dengue virus-infected patients progress to a potentially life-threatening severe dengue (SD) infection annually. To identify the immune features and temporal dynamics underlying SD progression, we performed deep immune profiling by mass cytometry of PBMCs collected longitudinally from SD progressors (SDp) and uncomplicated dengue (D) patients. While D is characterized by early activation of innate immune responses, in SDp there is rapid expansion and activation of IgG-secreting plasma cells and memory and regulatory T cells. Concurrently, SDp, particularly children, demonstrate increased proinflammatory NK cells, inadequate expansion of CD16+ monocytes, and high expression of the FcγR CD64 on myeloid cells, yet a signature of diminished antigen presentation. Syndrome-specific determinants include suppressed dendritic cell abundance in shock/hemorrhage versus enriched plasma cell expansion in organ impairment. This study reveals uncoordinated immune responses in SDp and provides insights into SD pathogenesis in humans with potential implications for prediction and treatment.

An 8-gene machine learning model improves clinical prediction of severe dengue progression.

BACKGROUND: Each year 3-6 million people develop life-threatening severe dengue (SD). Clinical warning signs for SD manifest late in the disease course and are nonspecific, leading to missed cases and excess hospital burden. Better SD prognostics are urgently needed. METHODS: We integrated 11 public datasets profiling the blood transcriptome of 365 dengue patients of all ages and from seven countries, encompassing biological, clinical, and technical heterogeneity. We performed an iterative multi-cohort analysis to identify differentially expressed genes (DEGs) between non-severe patients and SD progressors. Using only these DEGs, we trained an XGBoost machine learning model on public data to predict progression to SD. All model parameters were "locked" prior to validation in an independent, prospectively enrolled cohort of 377 dengue patients in Colombia. We measured expression of the DEGs in whole blood samples collected upon presentation, prior to SD progression. We then compared the accuracy of the locked XGBoost model and clinical warning signs in predicting SD. RESULTS: We identified eight SD-associated DEGs in the public datasets and built an 8-gene XGBoost model that accurately predicted SD progression in the independent validation cohort with 86.4% (95% CI 68.2-100) sensitivity and 79.7% (95% CI 75.5-83.9) specificity. Given the 5.8% proportion of SD cases in this cohort, the 8-gene model had a positive and negative predictive value (PPV and NPV) of 20.9% (95% CI 16.7-25.6) and 99.0% (95% CI 97.7-100.0), respectively. Compared to clinical warning signs at presentation, which had 77.3% (95% CI 58.3-94.1) sensitivity and 39.7% (95% CI 34.7-44.9) specificity, the 8-gene model led to an 80% reduction in the number needed to predict (NNP) from 25.4 to 5.0. Importantly, the 8-gene model accurately predicted subsequent SD in the first three days post-fever onset and up to three days prior to SD progression. CONCLUSIONS: The 8-gene XGBoost model, trained on heterogeneous public datasets, accurately predicted progression to SD in a large, independent, prospective cohort, including during the early febrile stage when SD prediction remains clinically difficult. The model has potential to be translated to a point-of-care prognostic assay to reduce dengue morbidity and mortality without overwhelming limited healthcare resources.

[Reducing hospitalization with the use of a dengue management algorithm in Colombia]. / Reducción de la hospitalización mediante un algoritmo de manejo del dengue en Colombia.

OBJECTIVE: Assess the impact of a dengue management algorithm on the hospitalization rate of patients with suspected disease in a primary care health facility in an endemic area of Colombia. METHODS: A quasi-experimental study was conducted at the local hospital in Piedecuesta, Santander, Colombia, based on comparison of two periods (18 weeks each), before and after use of the algorithm. This included recommendations for clinical diagnosis of dengue and the planning of follow-up visits and hemograms, as well as criteria for hospitalization and the discontinuation of follow-up. Hospitalization rates in the two periods were compared using the Poisson analysis. The population analyzed consisted of patients seen in the facility for acute febrile syndrome. For adjustment purposes, the number of dengue cases (IgM positive) identified in the municipality was included. RESULTS: Information was obtained on 964 patients in the first period and 1350 patients in the second. There were 44 and 13 hospitalizations during the respective periods. Use of the algorithm was associated with a significant reduction in the hospitalization rate (ratio: 0.21; 95% confidence interval; 0.11-0.39). This association did not change when adjusted for the number of dengue cases identified in the city. There were no significant differences in the rate of follow-up visits (P = 0.85) and hemograms (P = 0.24) in the two periods. There were no case fatalities. CONCLUSIONS: The results suggest that health care resources for dengue management can be optimized with the use of the algorithm.

Heterogeneity of dengue transmission in an endemic area of Colombia.

Population based serological surveys are the gold-standard to quantify dengue (DENV) transmission. The purpose of this study was to estimate the age-specific seroprevalence and the force of infection of DENV in an endemic area of Colombia. Between July and October 2014, we conducted a household based cross-sectional survey among 1.037 individuals aged 2 to 40 years living in 40 randomly selected locations in urban Piedecuesta, Santander, Colombia. In addition, we also enrolled 246 indviduals living in rural "veredas". Participants were asked to answer a questionnaire that included demographic, socioeconomic and environmental questions and to provide a 5 ml blood sample. Sera were tested using the IgG indirect ELISA (Panbio) kit to determine past DENV infection. The overall DENV seroprevalence was 70% (95% CI = 67%-71%), but was significantly higher in urban (81%, 95% CI = 78%-83%) as compared to rural (21%, 95% CI = 17%-27%) locations. Age was a major predictor of seropositivity, consistent with endemic circulation of the virus. Using catalytic models we estimated that on average, 12% (95%CI = 11%-13%) of susceptible individuals living in the city are infected by DENV each year. Beyond age, the only predictor of seropositivity in urban locations was prior history of dengue diagnosed by a physician (aPR 1.15, 95% CI = 0.98-1.35). Among participants living in rural settings, those that reported traveling outside of their vereda were more likely to be seropositive (aPR 3.60, 95%CI = 1.54-8.42) as well as those who were born outside of Santander department (aPR = 2.77, 95%CI = 1.20-6.37). These results are consistent with long term endemic circulation of DENV in Piedecuesta, with large heterogeneities between urban and rural areas located just a few kilometers apart. Design of DENV control interventions, including vaccination, will need to consider this fine scale spatial heterogeneity.

Biochemical alterations as markers of dengue hemorrhagic fever.

We evaluated biochemical alterations as predictors of dengue hemorrhagic fever (DHF). Patients with confirmed infection with dengue virus were prospectively evaluated for the first seven days of disease to determine their final clinical outcome. Serum samples taken 48-96 hours after onset of fever were used for biochemical tests. Of 199 patients, 30 developed DHF. Cases of DHF had higher levels of lactate dehydrogenase (LDH), creatine kinase (CK), and aspartate aminotransferase, and lower levels of albumin, total cholesterol, and triglycerides. Multivariate analysis showed that early alterations of CK (hazard ratio [HR] = 6.98, 95% confidence interval [CI] = 2.34-20.85, P = 0.001), LDH (HR = 3.19, 95% CI = 1.01-10.12, P < 0.05), and albumin (HR = 2.54, 95% CI = 1.09-5.92, P = 0.03) were associated with DHF. Triglyceride levels > 160 mg/dL were negatively associated with developing DHF (HR = 0.07, 95% CI = 0.01-0.59, P = 0.01). Early alterations of biochemical markers can predict DHF in patients with acute fever caused by dengue.

Characterization of the health condition of people convalescing from a dengue episode.

INTRODUCTION: Although dengue and its acute manifestations have been broadly described in the literature, the symptoms during the convalescence phase have so far been little studied.  OBJECTIVE: To describe the clinical manifestations of a population during the convalescence phase from a dengue episode.  MATERIALS AND METHODS: We conducted an observational study in individuals that were in the hospital after being serologically diagnosed with dengue. After being discharged from the hospital, they were visited in order to verify the persistence of clinical symptoms, fatigue (assessed using the Chalder's Fatigue Questionnaire) and quality of life (assessed with the EuroQoL-5D questionnaire). Significant fatigue was defined with a score equal to or greater than four in the corresponding scale. Participants with positive [+] fatigue signs were supervised by phone and/or by visiting them in their places of residence until the symptoms disappeared, with a maximum follow-up term of three months.  RESULTS: We included 32 individuals in the study (average age: 35 years old, 59% women) and a fatigue prevalence of 34.4% was observed (CI 95% 17.0-51.8). Sociodemographic differences were not defined as determinants with regard to fatigue; by contrast, we found a greater frequency of physical tiredness (100% vs 47.6%; p-0.005) and mental tiredness (54.6% vs 9.5%; p=0.010). Even though patients with fatigue had a poor quality of life, this sign was not statistically different from the group not reporting fatigue when we adjusted by age and sex (OR=5.5; CI 95% 0.83-36.5). In addition, fatigue scores dropped half point in average every 10 days of follow-up.  CONCLUSIONS: Our results demonstrated that the burden of disease in dengue has not been entirely described, as clinical signs are still present during the convalescence phase, and this represents an obstacle for the normal recovery of individuals.

Host biomarkers are associated with progression to dengue haemorrhagic fever: a nested case-control study.

OBJECTIVES: Dengue represents the most important arboviral infection worldwide. Onset of circulatory collapse can be unpredictable. Biomarkers that can identify individuals at risk of plasma leakage may facilitate better triage and clinical management. DESIGN: Using a nested case-control design, we randomly selected subjects from a prospective cohort study of dengue in Colombia (n=1582). Using serum collected within 96 hours of fever onset, we tested 19 biomarkers by ELISA in cases (developed dengue hemorrhagic fever or dengue shock syndrome (DHF/DSS); n=46), and controls (uncomplicated dengue fever (DF); n=65) and healthy controls (HC); n=15. RESULTS: Ang-1 levels were lower and angptl3, sKDR, sEng, sICAM-1, CRP, CXCL10/IP-10, IL-18 binding protein, CHI3L1, C5a and Factor D levels were increased in dengue compared to HC. sICAM-1, sEng and CXCL10/IP-10 were further elevated in subjects who subsequently developed DHF/DSS (p=0.008, p=0.028 and p=0.025, respectively). In a logistic regression model, age (odds ratio (OR) (95% CI): 0.95 (0.92-0.98), p=0.001), hyperesthesia/hyperalgesia (OR; 3.8 (1.4-10.4), p=0.008) and elevated sICAM-1 (>298ng/mL: OR; 6.3 (1.5-25.7), p=0.011) at presentation were independently associated with progression to DHF/DSS. CONCLUSIONS: These results suggest that inflammation and endothelial activation are important pathways in the pathogenesis of dengue and sICAM-1 levels may identify individuals at risk of plasma leakage.

[Biochemical alterations as prediction markers for the severity of illness in dengue fever patients]. / Alteraciones bioquímicas como marcadores predictores de gravedad en pacientes con fiebre por dengue.

INTRODUCTION: Dengue is the most important mosquito-borne infection in the world. There is evidence supporting the use of biochemical alterations as prediction tools for severity of illness in dengue. OBJECTIVE: To evaluate biochemical alterations as potential prediction markers for severity in dengue. MATERIALS AND METHODS: This was a case-control study nested in a cohort. We randomly selected 125 severe dengue cases and 120 controls with non-severe dengue for measuring LDH, CK, CRP and albumin serum levels using acute phase sera. To evaluate the predictive value for each biomarker, we established cut-off points with 90% sensitivity in detecting severe cases. RESULTS: There was association among the CRP levels < 9.8 mg/L (OR=0.04; 95%CI=0.02-0.08; p=0.000), <400 U/L LDH levels (OR=0.49; 95%CI=0.24-1.02; p=0.053) and <4 mg/dl albumin levels (OR=3.46; 95%CI=1.96-6.12; p=0.000) with the severity of dengue. In contrast, the CK levels showed no association with the severity of the disease. CONCLUSIONS: Our findings suggest an association of CRP, LDH and albumin levels with the severity of dengue. These biochemical tests could be used as predictive tools in the clinical course of the infection.

Caracterización del estado de salud de las personas en su periodo de convalecencia de un episodio de dengue / Characterization of the health condition of people convalescing from a dengue episode

Introducción. El dengue y sus manifestaciones agudas se han descrito ampliamente en la literatura, sin embargo, los síntomas en la fase de convalecencia se han estudiado poco. Objetivo. Describir las manifestaciones clínicas de una población durante su periodo de convalecencia de un episodio de dengue. Materiales y métodos. Se hizo un estudio observacional en sujetos que estuvieron hospitalizados con dengue diagnosticado por serología. Después del alta se les visitó para evaluar la persistencia de la sintomatología clínica, la fatiga (evaluada mediante el Fatigue Questionnaire de Chalder) y la calidad de vida (evaluada mediante el cuestionario EuroQoL-5D). Se determinó como fatiga significativa aquella con un puntaje igual o superior a cuatro en la escala empleada. Se hizo seguimiento telefónico y domiciliario de los participantes con fatiga hasta tres meses después del alta hospitalaria. Resultados. La prevalencia de fatiga en los 32 sujetos seleccionados (edad media: 35 años, sexo femenino: 59 %) fue de 34,4 % (IC 95% 17,0-51,8). No se observaron diferencias sociodemográficas en relación con la fatiga, pero sí con relación a una mayor frecuencia de cansancio físico (100,0 % Vs . 47,6 %; p=0,005) y mental (54,6 % Vs . 9,5 %; p=0,010). Aunque los pacientes con fatiga reportaron una peor calidad de vida, esta no fue estadísticamente diferente a la del grupo sin fatiga al ajustar por edad y sexo (OR=5,5; IC 95% 0,83-36,5). Además, el puntaje de fatiga decayó en promedio medio punto por cada diez días de seguimiento (p=0,007). Conclusiones. Estos resultados demuestran que la carga de enfermedad de la infección por el virus del dengue no se ha descrito del todo, pues en la fase de convalecencia se siguen presentando síntomas clínicos que dificultan la recuperación normal del individuo.

Introduction: Although dengue and its acute manifestations have been broadly described in the literature, the symptoms during the convalescence phase have so far been little studied. Objective: To describe the clinical manifestations of a population during the convalescence phase from a dengue episode. Materials and methods: We conducted an observational study in individuals that were in the hospital after being serologically diagnosed with dengue. After being discharged from the hospital, they were visited in order to verify the persistence of clinical symptoms, fatigue (assessed using the Chalder´s Fatigue Questionnaire) and quality of life (assessed with the EuroQoL-5D questionnaire). Significant fatigue was defined with a score equal to or greater than four in the corresponding scale. Participants with positive + fatigue signs were supervised by phone and/or by visiting them in their places of residence until the symptoms disappeared, with a maximum follow-up term of three months. Results: We included 32 individuals in the study (average age: 35 years old, 59% women) and a fatigue prevalence of 34.4% was observed (CI 95% 17.0-51.8). Sociodemographic differences were not defined as determinants with regard to fatigue; by contrast, we found a greater frequency of physical tiredness (100% vs 47.6%; p-0.005) and mental tiredness (54.6% vs 9.5%; p=0.010). Even though patients with fatigue had a poor quality of life, this sign was not statistically different from the group not reporting fatigue when we adjusted by age and sex (OR=5.5; CI 95% 0.83-36.5). In addition, fatigue scores dropped half point in average every 10 days of follow-up. Conclusions: Our results demonstrated that the burden of disease in dengue has not been entirely described, as clinical signs are still present during the convalescence phase, and this represents an obstacle for the normal recovery of individuals.

[Roll of antibodies antiplatelets in viral infection: a systematic review of literature]. / Papel de los anticuerpos antiplaquetarios en la infección viral: una revisión sistemática de la literatura.

INTRODUCTION: Thrombocytopenia is a frequent phenomenon in viral infections. Peripheral platelet destruction mediated by anti-platelet antibodies has been one of the proposed causal mechanisms. OBJECTIVE: Results were collected and analyzed from published studies on associations of human viral infections on anti-platelet antibodies and total platelet counts. MATERIALS AND METHODS: A PubMed search was conducted using the following terms: Viral infection (OR Virus diseases) AND antiplatelet antibody (OR thrombocytopenia) AND HIV (OR measles OR dengue OR chickenpox OR varicella OR Epistein Barr OR mumps OR rubella). Two hundred eighteen reference hits were obtained, 65 of which were relevant to this review. RESULTS: Antiplatelet antibody-mediated thrombocytopenia has been documented in cases of HIV, measles, dengue, chickenpox, Epstein-Barr, mumps and rubella. Moreover, the presence of these antibodies has been associated with severity the disease and thrombocytopenia in viral infections. CONCLUSIONS: Although the presence of antiplatelet antibodies was not the only mechanism for explaining the thrombocytopenia developed in these viral infections, their presence was associated with severity of thrombocytopenia and with the clinical presentation of these patients.

Predictors of spontaneous bleeding in patients with acute febrile syndrome from a dengue endemic area.

BACKGROUND: Spontaneous bleeding is a common complication of dengue and is associated with an increased mortality. OBJECTIVE: To evaluate early clinical manifestations and simple laboratory tests as predictors of spontaneous hemorrhage in patients with forms of acute febrile syndrome (AFS) such as dengue from an endemic area. STUDY DESIGN: A prospective cohort study was performed including 729 non-bleeding AFS patients who were enrolled during the first 4 days of disease. Basal evaluation included anamnesis, physical examination and complete blood cell count. Follow-up was extended at least until the sixth day of disease. Dengue infection was studied with paired serologic tests and viral isolation. Potential predictors of spontaneous bleeding were evaluated with bivariate and multivariate analysis. RESULTS: Incidence of outcome was not significantly different between the dengue group and those with non-dengue AFS. The tourniquet test was not associated with outcome (p=0.38). In a binomial regression model, the following variables were associated with outcome: age between 12 and 45 years (RR=2.22; 95% CI: 1.25-3.94), rash (RR=1.66; 95% CI: 1.25-2.2), vomiting (RR=1.46; 95% CI: 1.16-1.83), temperature >38 degrees C (RR=2.63; 95% CI: 1.6-4.33), leukocyte count <4500/microL (RR=1.87; 95% CI: 1.19-2.96), and platelet count <90.000/microL (RR=1.8; 95% CI: 1.1-2.94). With these variables a risk score was formulated that showed an area under ROC curve of 70.5% (95% CI: 64.9-76.2) to predict spontaneous bleeding. The score was useful for predicting bleeding in both dengue and non-dengue AFS groups. CONCLUSION: Some variables evaluated in the first days of disease helped to predict the risk of spontaneous bleeding in patients with dengue and non-dengue AFS.

[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.

Alteraciones bioquímicas como marcadores predictores de gravedad en pacientes con fiebre por dengue / Biochemical alterations as prediction markers for the severity of illness in dengue fever patients

Introducción. El dengue es la infección transmitida por mosquitos más importante en el mundo. Existe información de que las alteraciones bioquímicas pueden utilizarse como herramientas predictoras de gravedad del dengue. Objetivo. Evaluar las alteraciones bioquímicas como posibles marcadores predictores de gravedad del dengue. Materiales y métodos. Se llevó a cabo un estudio de casos y controles anidado en una cohorte. Se seleccionaron al azar 125 casos con dengue grave y 120 controles con dengue no grave para evaluar los niveles séricos de lactato-deshidrogenasa (LDH), creatina cinasa (CK), proteína C reactiva (PCR) y albúmina, en sueros obtenidos en las primeras horas de la enfermedad. Para evaluar el valor diagnóstico de cada biomarcador, se establecieron puntos de corte con una sensibilidad del 90 % en la detección de casos graves. Resultados. Se observó una asociación entre los niveles de PCR por debajo de 9,8 mg/l (OR=0,04; IC 95% =0,02-0,08 ; p=0,000), de LDH inferiores a 400 U/L (OR=0,49; IC 95% =0,24-1,02; p=0,053) y de albúmina menor de 4 mg/dl (OR=3,46; IC 95% =1,96-6,12; p=0,000), con la gravedad del dengue. En contraste, los niveles de la CK no mostraron asociación con la gravedad de la enfermedad. Conclusiones. Los hallazgos de nuestro estudio sugieren una asociación de los niveles de PCR, LDH y albúmina con la gravedad del dengue. Estas pruebas bioquímicas podrían ser utilizadas como herramientas predictoras del curso clínico de la infección.

Introduction: Dengue is the most important mosquito-borne infection in the world. There is evidence supporting the use of biochemical alterations as prediction tools for severity of illness in dengue. Objective: To evaluate biochemical alterations as potential prediction markers for severity in dengue. Materials and methods: This was a case-control study nested in a cohort. We randomly selected 125 severe dengue cases and 120 controls with non-severe dengue for measuring LDH, CK, CRP and albumin serum levels using acute phase sera. To evaluate the predictive value for each biomarker, we established cut-off points with 90% sensitivity in detecting severe cases. Results: There was association among the CRP levels < 9.8 mg/L (OR=0.04; 95%CI=0.02-0.08; p=0.000), <400 U/L LDH levels (OR=0.49; 95%CI=0.24-1.02; p=0.053) and <4 mg/dl albumin levels (OR=3.46; 95%CI=1.96-6.12; p=0.000) with the severity of dengue. In contrast, the CK levels showed no association with the severity of the disease. Conclusions: Our findings suggest an association of CRP, LDH and albumin levels with the severity of dengue. These biochemical tests could be used as predictive tools in the clinical course of the infection.

Linfocitos atípicos en dengue: papel en el diagnóstico y pronóstico de la enfermedad: Revisión sistemática de la literatura / Atypical lymphocytes in dengue: role in diagnosis and prognosis of disease: A systematic review of literature / Linfócitos atípicos em dengue: o papel no diagnóstico e prognóstico da doença: Revisão sistemática da literatura

El dengue es la arbovirosis de mayor incidencia mundial y una importante causa de morbilidad y mortalidad. Debido a que la enfermedad se presenta en principio como un cuadro febril inespecífico, se requieren herramientas que permitan reconocer y clasificar a los pacientes con dengue en forma temprana. Un parámetro de utilidad en este sentido puede ser la presencia de linfocitos atípicos. Objetivo: revisar los resultados de los trabajos originales existentes en la literatura sobre linfocitos atípicos e infección por virus dengue y su papel en el diagnóstico y pronóstico de la enfermedad. Materiales y métodos: para la revisión se emplearon los motores de búsqueda PubMed y Lilacs, bajo la combinación de términos Dengue AND Atypical lymphocyte (OR Reactive lymphocyte, OR Turk cell), limitando los hallazgos a estudios en humanos. La información obtenida fue clasificada por su contenido. Solo se incluyeron en el presente trabajo los estudios relevantes para el tema. Resultados: se ajustaron 68 referencias a la estrategia de búsqueda empleada, pero solo doce correspondían al objeto de la revisión. Todos los estudios incluidos reportaron presencia de linfocitos atípicos como hallazgo hematológico particular en pacientes con dengue y aunque no fue un hallazgo específico de la enfermedad, su concentración fue significativamente superior en estos pacientes, sobre todo en cuadros severos de la misma. Conclusiones: de acuerdo con la evidencia encontrada, puede considerarse que existe una asociación entre la presencia de linfocitos atípicos y la infección por el virus dengue; sin embargo, la intensidad y utilidad de este hallazgo requiere mayor estudio y análisis.

Dengue is the arbovirus infection with the highest incidence in the world and a major cause of morbidity and mortality. Disease onset presents as a nonspecific febrile illness, and therefore, tools are required to identify and classify dengue patients at early stage. An useful parameter is the presence of atypical lymphocytes. Objective: to collect and analyze results from existing published studies on atypical lymphocytes and dengue infection, and its effect on diagnosis and prognosis of disease. Materials and methods: was conducted a PubMed and LILACS search under the terms: Dengue AND Atypical lymphocyte (OR Reactive lymphocyte, OR Turk cell), limiting the findings to human studies. The information was classified by its content. Only studies relevant to the topic were included in this study. Results: 68 references were identified using the search strategy, but only 12 met the inclusion criteria. All included studies reported the presence of atypical lymphocytes as particular hematologic finding in patients with dengue, and although it is not a classical specific finding of the disease, their concentrations were significantly higher in these patients, especially in severe forms of the disease. Conclusions: according to this evidence, there may be an association between the presence of atypical lymphocytes and dengue virus infection, but the intensity and usefulness of this finding requires further study and analysis.

O dengue é a arbovírus de maior incidência mundial e uma importante causa de morbidade e mortalidade. Devido a que a doença se apresenta em princípio como um quadro febril inespecífico, requerem-se ferramentas que permitam reconhecer e classificar aos pacientes com dengue de forma rápida. Um parâmetro de utilidade neste sentido pode ser a presencia de linfócitos atípicos. Objetivo: revisar os resultados dos trabalhos originais existentes na literatura sobre linfócitos atípicos e infecção por vírus dengue e seu papel no diagnóstico e prognóstico da doença. Materiais e métodos: para a revisão se empregaram os motores de busca PubMed e Lilacs, sob a combinação de termos Dengue AND Atypical lymphocyte (OR Reactive lymphocyte, OR Turk cell), limitando os resultados a estudos humanos. A informação obtida foi classificada por seu conteúdo. Só incluíram-se no presente trabalho os estudos relevantes para o tema. Resultados: se ajustaram 68 referencias à estratégia de procura empregada, mais só doze correspondiam ao objeto da revisão. Todos os estudos incluídos reportaram presencia de linfócitos atípicos como descoberta hematológica particular em pacientes com dengue e ainda não fosse uma descoberta típica da doença, sua concentração foi significativamente superior nestes pacientes, especialmente em quadros severas da doença. Conclusões: de acordo com a evidência encontrada, pode se considerar que existe uma associação entre a presencia de linfócitos atípicos e a infecção pelo vírus dengue; no entanto, a intensidade e utilidade desta descoberta, requere maior estudo e análise.

[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.

[Low concordance between early clinical suspicion of dengue and its serological confirmation]. / Dificultad para el diagnóstico clínico temprano del dengue en un área endémica y su impacto sobre el manejo médico inicial.

BACKGROUND: Early detection of dengue could help to prevent its complications. The usefulness of clinical criteria for diagnosis of the disease must be ascertained. AIMS: To assess the correlation between laboratory and clinical diagnosis of dengue, done during the first consultation in the emergency room. To estimate the impact of clinical diagnosis on the initial medical treatment. PATIENTS AND METHODS: Patients older than 5 years with an acute febrile syndrome that consulted during the first 72 hours of disease, during 2004, at an emergency room in Bucaramanga, Colombia, were studied. Symptoms and the clinical diagnosis of the initial evaluation were registered. Paired serum samples for dengue specific ELISA-IgM test and viral isolation were obtained. The association of the initial clinical diagnosis with early symptoms, initial medical treatment and laboratory diagnosis was evaluated. RESULTS: One hundred sixty eight patients were enrolled (54 with confirmed dengue infection). Clinical diagnosis of dengue was associated to a higher request of complete blood counts (p = 0.01) and greater use of intravenous fluids (p = 0.02). However, clinical diagnosis was not correlated with the laboratory diagnosis (p = 0.15). The percentage of agreement was less than would be expected by chance (Kappa = -0.1). Headache was associated to the initial clinical diagnosis of dengue (p = 0.03), and only metrorrhagia was associated with confirmed dengue infection (p = 0.04). CONCLUSIONS: The early clinical suspicion of dengue has a low concordance with the laboratory confirmation of the disease.

[Complications associated to severe thrombocytopenia in patients with dengue]. / Complicaciones asociadas a la trombocitopenia profunda en pacientes con dengue.

BACKGROUND: Thrombocytopenia is a distinctive characteristic of dengue; however, few studies have related thrombocytopenia with its clinical severity. AIM: To identify the complications of dengue, associated to severe thrombocytopenia, defined as a platelets count below 50,000/mm3). PATIENTS AND METHODS: Patients with clinical and serologic (positive IgM) diagnosis of dengue, consulting at hospitals located in Santander, Colombia, during the period 1993-1998, were studied. Clinical findings and laboratory tests (including hematocrit and platelets counts) were registered. The association between severe thrombocytopenia and the presence of complications, such as hemorrhagic manifestations (positive tourniquet test, petechiae, ecchymoses, bleeding from gums, epistaxis, hematemesis, hematuria and metrorrhagia) and signs of plasma leakage (pleural effusions and haemoconcentration), were evaluated using a univariate and multivariate analysis. RESULTS: Of the 790 patients enrolled, 502 had a platelet count below 50,000/mm3. Severe thrombocytopenia was associated with hemorrhagic manifestations (OR= 3.16; 95% CI: 2.09-4.76; p <0.0001) and signs of plasma leakage (OR= 2.67; 95% CI: 1.86-3.84; p <0.0001). The associations between severe thrombocytopenia and the complications of dengue (with exception of bleeding from gums, hematuria and metrorrhagia), were confirmed with the multivariated analysis (p <0.05). CONCLUSION: There was a strong association between deep thrombocytopenia and the severity of dengue.

Reducción de la hospitalización mediante un algoritmo de manejo del dengue en Colombia / Reducing hospitalization with the use of a dengue management algorithm in Colombia

OBJETIVO: Evaluar el efecto de un algoritmo de manejo del dengue sobre la tasa de hospitalización de pacientes con sospecha de esta enfermedad, en una institución de salud de primer nivel en un área endémica en Colombia. MÉTODOS: Se realizó un estudio cuasiexperimental en el hospital local de Piedecuesta, Santander, Colombia, basado en la comparación de dos períodos (de 18 semanas cada uno), antes y después de la implementación del algoritmo. Este incluía recomendaciones para diagnosticar clínicamente el dengue y programar consultas de control y hemogramas, así como criterios de hospitalización y de suspensión del seguimiento. Se compararon las tasas de hospitalización en los dos períodos empleando el análisis de Poisson. La población analizada consistió en los pacientes que consultaron por síndrome febril agudo. Para el ajuste se incluyó el número de casos con dengue (IgM positivos) identificados en el mismo municipio. RESULTADOS: e obtuvo información de 964 pacientes en el primer período y de 1 350 en el segundo, y en dichos períodos hubo 44 y 13 hospitalizaciones, respectivamente. La implementación del algoritmo se asoció a una reducción significativa de la tasa de hospitalización (razón de tasas: 0,21; intervalo de confianza de 95 por ciento 0,11 a 0,39). Esta asociación no se modificó cuando se ajustó por el número de casos de dengue identificados en la ciudad. No hubo diferencias significativas en la tasa de consultas de control (P = 0,85) y de hemogramas (P = 0,24) en los dos períodos. No hubo casos fatales. CONCLUSIONES: Los resultados sugieren que es posible optimizar los recursos asistenciales en el manejo del dengue mediante la implementación del algoritmo.

OBJECTIVE: Assess the impact of a dengue management algorithm on the hospitalization rate of patients with suspected disease in a primary care health facility in an endemic area of Colombia. METHODS: A quasi-experimental study was conducted at the local hospital in Piedecuesta, Santander, Colombia, based on comparison of two periods (18 weeks each), before and after use of the algorithm. This included recommendations for clinical diagnosis of dengue and the planning of follow-up visits and hemograms, as well as criteria for hospitalization and the discontinuation of follow-up. Hospitalization rates in the two periods were compared using the Poisson analysis. The population analyzed consisted of patients seen in the facility for acute febrile syndrome. For adjustment purposes, the number of dengue cases (IgM positive) identified in the municipality was included. RESULTS: Information was obtained on 964 patients in the first period and 1350 patients in the second. There were 44 and 13 hospitalizations during the respective periods. Use of the algorithm was associated with a significant reduction in the hospitalization rate (ratio: 0.21; 95 percent confidence interval; 0.11-0.39). This association did not change when adjusted for the number of dengue cases identified in the city. There were no significant differences in the rate of follow-up visits (P = 0.85) and hemograms (P = 0.24) in the two periods. There were no case fatalities. CONCLUSIONS: The results suggest that health care resources for dengue management can be optimized with the use of the algorithm.