Laboratory diagnosis for dengue

Abstract

Effective epidemiological surveillance for dengue fever must include the ability of routine laboratory confirmation and monitoring of circulating serotypes. Laboratory surveillance is essential so that differential diagnosis could be performed between dengue fever and other acute febrile diseases, due to clinical similarities exhibited.In general, the dengue´s laboratory diagnosis aims: 1) laboratory, serologic and/or virologic infection´s confirmation; 2) identification of circulating serotypes; 3) laboratory confirmation of severe and fatal cases; 4) support for epidemiological investigations to determine the levels of disease transmission and 5) performance of molecular studies in order to identify existing genotypes in the region (VORNDAM & KUNO, 1997). For adequate effectiveness of the laboratory diagnosis, it is required to take into account the appropriate time for blood sampling and to what type of test it is designated. This information is of great importance when interpreting the results. Laboratory criteria for confirmation of casesThe positive results for one of the following methods will confirm the case by laboratory criterion: 1) isolation and identification of dengue virus (DENV) in blood sample (serum, plasma), organ fragments collected post mortem (liver, spleen, kidney, heart, lung, nervous system); 2) detection of viral nucleic acid (RNA) using the reverse transcription-polymerase chain reaction (RT-PCR) technique; 3) detection of non-structural 1 (NS1) protein (antigen) in serum and/or plasma sample; 4) detection of IgM antibodies specific for dengue in a single serum sample; 5) increase of four times or more in the IgG antibodies titers; hemagglutination inhibiting antibodies, and/or neutralizing antibodies in paired serum samples, collected during the acute phase of illness and convalescence, for one or more DENV antigens; 6) demonstration of viral antigen in necropsied tissues by immunohistochemistry (WHO, 1997;GUZMAN & KOURI, 2004). Virologic diagnosisFor isolation of the virus, the blood collection should be performed preferably within the first five to six days of symptoms, during the acute phase. This sample will also be used for detection of viral RNA by RT-PCR, for real time RT-PCR and also for detection of NS1 antigen. Virus isolation is performed usually in cell cultures of mosquito (clone C6/36, Aedes albopictus; TRA-284, Toxorhynchites amboinenses and AP-61, Aedes pseudoscutellaris), (IGARASHI, 1978). Continuous lines of vertebrates, such as VERO, BHK-21, LLC-MK2, and also inoculation into animals and mosquitos can also be used. The isolated viruses can be identified by indirect immunofluorescence using monoclonal antibodies against all four serotypes (HENCHAL et al., 1982). Molecular diagnostics by RT-PCRThe extraction of viral RNA from the samples is carried out using in house techniques (Trisol, Silica/Guanidine isothiocyanate, etc), by column-extraction kits and automated equipment. For detection of viral RNA and identification of serotypes by RT-PCR technique, the protocol ...

The Sensitivity Comparison of Immunodiagnostic Assays for Diagnosing Dengue Fever

“…Rapid investigation is mandatory for dengue virus infection to properly manage the patient [1]. For the diagnosis of dengue infection various laboratory tests are employed to monitor circulatory serotypes [2,3]. These tests are performed by several methods such as isolation of virus from cell cultures, detection of nucleic acid by polymerase chain reaction (PCR), or viral antigen detection.…”

A Study of Seroprevalence and Changing Trend of Dengue in a Tertiary Care Hospital in Manipur

“…Anti-dengue IgG antibody are produced after one week and attain maximum after 2-3 weeks and thereafter remained in circulation lifelong; in secondary infection IgG antibody are distributed at high level in acute stage of infection, while IgM at low level. [18] For any virus infection the standard serological test, hemagglutination inhibition, neutralisation test, indirect immunofluorescence antibody test, Enzyme-Linked Immunosorbent Assay (ELISA), compliment fixation test or rapid immunochromatography test can be used. Out of these tests, ELISA is the most widely used method for routine diagnosis of dengue infection for its high sensitivity, specificity and also for its simplicity and cost effectiveness.…”

“…[19] Detection of NS1 (Non-Structural highly conserved glycoprotein-1) antigen is a new approach for the diagnosis of acute dengue, as it was found circulating in the blood during acute phase of disease in the patients from first day to 9 th day of fever. [18,19] Soluble form of NS1 antigen can be detected in the blood stream, test such as antigen capture-Enzyme-Linked Immunosorbent Assay (ELISA), lateral flow antigen detection by rapid method and measurement of NS1 specific immunoglobulin IgM and IgG responses have been developed. [20] The seNS1tivity of NS1 antigen capture ELISA was significantly higher in acute primary dengue than in acute secondary dengue.…”

Perfil epidemiológico dos casos notificados de dengue no município de Primavera do Leste – MT, entre o período de 2014 a 2017

“…O exame laboratorial para confirmação da dengue é realizado conforme recomendações da Vigilância Epidemiológica de cada região e, em períodos epidêmicos, é indicada para todo o paciente grave com dúvidas no diagnóstico (DIAS et al, 2010). O diagnóstico laboratório deve ser realizado para a confirmação sorológica e identificação viral, e para oferecer suporte para investigações epidemiológicas, pois esta doença apresenta similaridades clínicas com outras doenças febris agudas (CORDEIRO, 2012).…”