Laboratory Diagnosis Of Dengue Infection Research Articles

Dengue: A review of laboratory diagnostics in the vaccine age

Background. Dengue is an important arboviral infection of considerable public health significance. It occurs in a wide global belt within a variety of tropical regions. The timely laboratory diagnosis of Dengue infection is critical to inform both clinical management and an appropriate public health response. Vaccination against Dengue virus is being introduced in some areas. Discussion. Appropriate diagnostic strategies will vary between laboratories depending on the available resources and skills. Diagnostic methods available include viral culture, the serological detection of Dengue-specific antibodies in using enzyme immunoassays (EIAs), microsphere immunoassays, haemagglutination inhibition or in lateral flow point of care tests. The results of antibody tests may be influenced by prior vaccination and exposure to other flaviviruses. The detection of non-structural protein 1 in serum (NS1) has improved the early diagnosis of Dengue and is available in point-of-care assays in addition to EIAs. Direct detection of viral RNA from blood by PCR is more sensitive than NS1 antigen detection but requires molecular skills and resources. An increasing variety of isothermal nucleic acid detection methods are in development. Timing of specimen collection and choice of test is critical to optimize diagnostic accuracy. Metagenomics and the direct detection by sequencing of viral RNA from blood offers the ability to rapidly type isolates for epidemiologic purposes. Conclusion. The impact of vaccination on immune response must be recognized as it will impact test interpretation and diagnostic algorithms.

Sudden Infant Death in an 8-Month-Old Baby With Dengue Virus Infection

Sudden infant death due to dengue virus infection is very rare. An 8-month-old male infant was found unresponsive during a nap in his nursery school. We emphasize the usefulness of dengue viral antigens as a postmortem diagnostic technique to demonstrate the presence of virus in human tissue specimens by immunohistochemistry and Western blotting.

A comparative retrospective study of RT-PCR-based liquid hybridization assay for early, definitive diagnosis of dengue

Dengue is an important flaviviral infection in tropical and subtropical regions. Early diagnosis of dengue infection helps in monitoring the disease, determining when hospital admission is necessary and reducing case fatalities. The objective of this study was to carry out a retrospective comparison of an RT-PCR-based liquid hybridization (RT-PCR-LH) assay with PCR amplification, virus isolation and serological techniques for laboratory diagnosis of dengue infection. Amplified products of non-structural 3 gene were hybridized with a mixture of four dengue type-specific DNA probes in liquid phase. The assay was validated in a comparative retrospective study using acute serum samples collected from 119 fever patients with or without dengue, confirmed by haemagglutination inhibition (HAI) assay, the gold standard assay for diagnosis of dengue infection. The RT-PCR-LH assay was highly specific for dengue and, as an early laboratory diagnostic method, had 100% sensitivity in detecting dengue patients confirmed by HAI assay. A high analytical sensitivity of two fluorescent focus units of dengue virus/reaction was achieved. This RT-PCR-LH assay using a single serum specimen offers distinct advantages of specificity and sensitivity over other diagnostic techniques for early definitive laboratory diagnosis of dengue infection when serological methods are of little value.

Semi-quantitative dot immunoassay for detection of IgM anti-dengue antibodies in human sera

Laboratory diagnosis of dengue infection plays an important role for case nlanagenrent and disease control. Unfortunately, many of the available laboratory tests are not appropriate in tet'ms of rapidity and .simplicity. H ere, we report a new format of semiquantitative dot immunoassay for detection of IgM-anti dengue antibodies in human sera entltloyittg biotinylated-dengue antigens which is simple in term of methodoLogy and rapid in ternt of the lest result. Tlrc results indicated that tlrc new test is sensitive for diagnosis of secondary dengue infection. The test result can be obtained withinfour and a halfhours.

A comparative, prospective study of serological, virus isolation and PCR amplification techniques for the laboratory diagnosis of dengue infection

Serum specimens from 58 hospitalized patients with clinical suspicion of dengue fever were obtained in a prospective study. All 58 acute serum samples were tested by IgM capture enzyme-linked immunosorbent assay (ELISA) and commercial Dengue Blot serological assays, virus isolation in C6/36 mosquito cells, and polymerase chain reaction (PCR) by single-step and semi-nested approaches using NS3 gene primers. Of the 22 acute sera positive by any one of the five methods, 17 (77.3%) were positive by IgM capture ELISA, 12 (54.5%) by Dengue Blot, none (0%) by virus isolation, two (9.1%) by single-step PCR and three (13.6%) by the more sensitive semi-nested PCR approach. Dengue virus type 2 was detected by both PCR assays. Convalescent sera were also collected from 13 of the 58 patients and haemagglutination inhibition (HI) tests performed on paired serum samples. HI confirmed five positive sera, while the other eight sera were negative or inconclusive. In our study cohort, although PCR was more sensitive than virus isolation for detecting the presence of dengue virus in sera, serological techniques were able to identify more dengue infections than both PCR and virus isolation. These results may be attributed to the collection of serum samples after the period of viraemia which is appropriate for serological assays, in contrast to early or highly viraemic sera which are more suitable for PCR and virus isolation methods.