Microbiological Profile of Dengue, Malaria and Chikungunya among Patients Presenting with Acute Febrile Illness in a Tertiary Care Hospital

Abstract

Background: Acute febrile illness (AFI) is a leading cause of hospital attendance in India, and dengue, malaria and chikungunya share overlapping clinical features and seasonality. Accurate laboratory-based etiological profiling is essential for appropriate management and for guiding public health action.
Aim and objectives: To determine the microbiological profile of dengue, malaria and chikungunya among patients with AFI, and to study their demographic, seasonal, clinical, laboratory and outcome characteristics, including co-infections.
Materials and methods: This hospital-based, cross-sectional observational study was conducted in the Department of Microbiology of a tertiary care hospital from July 2025 to June 2026. Four hundred consecutive patients with AFI were enrolled. Dengue was diagnosed by NS1 antigen and IgM/IgG capture ELISA, malaria by Giemsa-stained peripheral smear and rapid diagnostic test (RDT), and chikungunya by IgM capture ELISA. Other etiologies were evaluated by blood culture, Widal test, scrub typhus and leptospira IgM ELISA, and urine culture. Data were analysed using the chi-square test, Fisher exact test and ANOVA; p < 0.05 was significant.
Results: The mean age was 32.8 ± 16.4 years and 59.5% were males. A specific vector-borne etiology was identified in 202 patients (50.5%). Dengue was the commonest (125; 31.3%), followed by malaria (52; 13.0%) and chikungunya (41; 10.3%); co-infections occurred in 15 patients (3.8%). Positivity peaked during the monsoon and post-monsoon months (September–October). Dengue positivity differed significantly by season (p < 0.001), and malaria was significantly more frequent in males (p = 0.033). NS1 and IgM positivity in dengue were 62.4% and 56.8%, respectively, with NS1 positivity declining and IgM rising after day 5 of illness. Plasmodium vivax accounted for 63.5% of malaria cases and P. falciparum for 30.8%; RDT showed a higher yield (94.2%) than peripheral smear (88.5%). Arthralgia (87.8%) characterised chikungunya, chills and splenomegaly characterised malaria, and thrombocytopenia (78.4%) characterised dengue. Overall mortality was 1.5%.
Conclusion: Dengue, malaria and chikungunya together accounted for half of all AFI cases, with significant seasonal clustering and a non-negligible burden of co-infection. A combined diagnostic approach (NS1 plus IgM for dengue; smear plus RDT for malaria) and early, simultaneous testing during the monsoon season are recommended.