Challenges in the early diagnosis of dengue: A practical approach

Abstract

Introduction: Mosquito borne diseases such as dengue, chikungunya, and malaria are clinically indistinguishable and diagnosis is solely upon laboratory findings. In an endemic area, early diagnosis of dengue requires detection of all the three markers (NS1, immunoglobulin (Ig) M and G simultaneously to distinguish primary and secondary infection. Aim: To assess the value of all dengue markers by rapid immunochromatography test (ICT) in early diagnosis. Materials and Methods: A total of 120 blood samples collected from patients with fever were tested for dengue markers by rapid ICT. Results: Of the 120 samples tested, 41 (34%) were positive for one or more of the three markers. Of the 41 samples, NS1 only was positive in 10 (24%), IgM only in two (5%), IgG only in 10 (24%), NS1 and IgM in two (5%), NS1 and IgG in one (2%), IgM and IgG in eight (20%), and triple positive (NS1, IgM, and IgG) in eight (20%). Of the 41 cases, NS1 alone was detected in two patients (5%) who came on 1-2 days of illness. Conclusion: Rapid ICT detecting NS1, IgM, and IgG is much valuable in emergencies as a screening test for early diagnosis and management. Rapid tests should be confirmed by enzyme-linked immunosorbent assay (ELISA). Still, gold standard tests in the diagnosis of dengue are virus isolation or molecular methods.