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.

<p class="p1"><span class="s1"><strong>Introducción.</strong> 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.</span></p><p class="p1"><strong>Objetivo.</strong> Evaluar el desempeño de cuatro pruebas ELISA en muestras de suero y plasma de casos sospechosos de dengue.  </p><p class="p1"><strong>Materiales y métodos.</strong> 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. </p><p class="p1"><strong>Resultados.</strong> 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). </p><p class="p1"><span class="s1"><strong>Conclusión.</strong> 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. </span></p>

BackgroundDengue is the most widely distributed arboviral disease in tropical and subtropical countries. Most suspected cases are diagnosed according to the clinical criteria, and early diagnosis is difficult. Moreover, in underdeveloped countries, several factors continue to challenge the diagnosis and surveillance of dengue cases. This study aimed to design a diagnostic algorithm using rapid diagnostic tests (RDTs), ELISA tests, and clinical and hematological variables to confirm dengue cases in febrile patients in Colombia.MethodsAltogether, 505 samples were collected. Serum samples were evaluated by RDTs (IgM and IgG antibodies and NS1 antigen), capture IgM and IgG ELISAs, and endpoint hemi-nested RT-PCR assay (qualitative). We statistically analyzed the performance of individual tests to determine the most useful ones to confirm dengue cases accurately.ResultsIndividual results for IgM, IgG, and NS1 RDTs yielded lower sensitivity and specificity values than the reference standard. High sensitivity and specificity were obtained after combining IgM and NS1 ELISA results (96.3% and 96.4%) and NS1 RDT plus IgM ELISA results (90.3% and 96.2%), respectively. Adjusted odds ratios (aORs) were calculated for clinical variables and laboratory tests to differentiate dengue from other febrile illnesses (OFI). This approach showed that myalgia, abdominal tenderness, and platelet count were identified with higher sensitivity to confirm dengue cases. IgM RDT and NS1 RDT differentiated dengue cases from OFI. A positive IgM RDT or a positive NS1 RDT combined with specific signs or symptoms confirmed 81.6% of dengue cases. A combination of clinical findings and a positive NS1 RDT or positive ELISA IgM confirmed 90.6% of the cases.ConclusionOur findings showed that clinical diagnoses in pediatric population alone cannot confirm true dengue cases and needs to be complemented by laboratory diagnostic tests. We also demonstrate the usefulness of combining clinical criteria with RDTs, suggesting that their implementation with the IgM ELISA test improves dengue case confirmation.

Background Dengue is the most widely distributed arboviral disease in tropical and subtropical countries. Early diagnosis is difficult, and most of the suspected cases are diagnosed according to clinical criteria. In underdeveloped countries, laboratory tests are done on a proportion of dengue with warning signs or severe dengue suspect cases. This study aimed to design a diagnostic algorithm using rapid diagnostic tests (RDT), ELISA tests together with clinical and hematology variables to confirm dengue cases in febrile patients from an endemic area in Colombia. Methods and results. A total of 505 samples were collected from patients with the acute febrile syndrome (<7 days) assisted to the Municipal Hospital in Girardot (Colombia). Serum samples were evaluated by rapid diagnostic tests -RDT- (IgM and IgG antibodies and NS1 antigen immunochromatographic assay), capture ELISAs (IgM, IgG, and NS1 antigen), and by RT-PCR. We analyzed individual test performance to determine which were the most useful to confirm dengue cases. Individual results for IgM, IgG, and NS1 RDT yield low sensitivity and specificity values than the reference standard. A high sensitivity (96.3%) and specificity (96.4%) were obtained after combining the IgM and NS1 ELISAs results. The analysis using the combined NS1 RDT and IgM ELISA results showed 90.3% sensitivity and 96.2% specificity. Adjusted odd ratios (aOR) were calculated including data from symptoms, signs, and diagnostic laboratory tests to differentiate dengue from other febrile illnesses (OFI). Myalgia (aOR: 1.87, CI95%: 1.04-3.38), abdominal tenderness (aOR: 1.89, CI95%: 1.14-3.10), platelets count <140.000/mm3 (aOR: 2.19 CI95%: 1.31-3.67). The analysis using the results of the diagnostic test yields significant ratios for IgM RDT (aOR:2.63 CI95%: 1.59-4.33) and NS1 RDT also differentiate dengue cases from OFI. Combined positive IgM or NS1 RDT and the one that combined positive NS1 RDT or IgM ELISA detect dengue cases in 81.6% and 90.6%, respectively (p<0.001). Conclusion. Our findings showed that only clinical diagnosis does not confirm true dengue cases dengue and needs to be complemented by laboratory diagnostic tests to establish the diagnosis. We also demonstrate the usefulness of rapid tests in diagnosis, suggesting their implementation with IgM ELISA test to better confirm dengue cases.