Introduction: Dengue virus infection a vector borne disease affecting more than 50 million people worldwide annually. It is distributed in tropical and subtropical regions of the world, abundant in urban and semi-urban areas. It is the disease that spreads by bite of Aedes aegypti and Aedes albopictus mosquitoes. The virus being a RNA virus belongs to Flaviviridae family. The four serotypes of Dengue virus are DENV-1, DENV-2, DENV-3, and DENV-4 which have distinct antigenicity complex.
Materials and Methods: This study was conducted in Microbiology Department, Government Stanley Medical College, Chennai, during the period Jan 2018 to Dec 2018 with 120 blood samples from patients of suspected dengue fever. Samples were selected by stratified random sampling method into three strata and each strata consisting of 40 samples based on duration of fever. All the samples were subjected to procedure for both NS1 antigen and IgM antibodies.15 NS1 positives samples with duration of fever less than 5 days were serotyped by PCR.
Results: A total of 18 cases had NS1 antigen, 26 cases had IgM antibodies and 27 cases had both. A combination of the two tests detected a total of 44 cases. The chance of detection of NS1antigen decreased with duration of fever and IgM antibodies increased with duration of fever. The serotyping detected were DENV1 and DENV3
Conclusion: NS1 antigen detection by ELISA is useful in early phase of infection. A combination of NS1 ELISA and IgM ELISA have high sensitivity depending upon the duration of illness. Detection of DENV1 and DENV3 by PCR procedure helps to know the presence of prevailing serotype in this particular region which would be a good guide to predict the recurrence of outbreak and for efficient prevention and management.
Serotyping, IgM antibodies, NS1 antigen, Viraemia