The Epidemiology of Arboviral Infections in the Non-monsoon Season: A Clinical and Geospatial Analysis From a Tertiary-Care Setting

TL;DR

This study found that about a third of adults with suspected arboviral infections at a hospital during the non-monsoon season had confirmed infections, mainly dengue.

Contribution

The study provides new insights into the prevalence of arboviral infections outside the monsoon season in a tertiary-care setting.

Findings

Dengue was the most common confirmed arboviral infection, affecting 22.7% of participants.

Arboviral infections were found in 30.4% of clinically suspected cases during the non-monsoon season.

Gender was statistically associated with hospital admission among confirmed arboviral cases.

Abstract

Introduction: Arboviral infections have a severe impact on human health. The primary objective of our study was to determine the proportion of laboratory-confirmed dengue, Japanese encephalitis, Zika, and chikungunya infections among adults presenting with clinically suspected arboviral illness to a tertiary-care hospital during the non-monsoon season. The secondary objective was to assess the geospatial distribution of confirmed cases. We also aimed to identify factors associated with hospital admission among the confirmed cases.

Methods: A cross-sectional study was done among 507 adult cases with clinically diagnosed arbovirus infection. A pretested questionnaire was used to collect sociodemographic data and clinical features. Blood samples were collected and tested for dengue NS1 antigen, dengue IgM antibody, chikungunya IgM antibody, and Japanese encephalitis IgM antibody by enzyme-linked immunosorbent assay (ELISA). RT-PCR was done to test for Zika virus RNA.

Result: The mean (SD) age of the participants was 38.0 (13.9) years. One hundred fifteen (22.7%) participants had dengue infection, 33 (6.5%) were positive for chikungunya IgM, and six (1.2%) were positive for Japanese encephalitis IgM. However, none tested positive for the Zika virus. Hence, a total of 30.4% of participants had arboviral infection. Gender was found to be statistically associated with hospital admission among the arboviral-positive patients.

Conclusion: A third of clinically suspected adult cases during the non-monsoon period in this hospital-based cross-sectional investigation had laboratory-confirmed arboviral infection, predominantly dengue. The results highlight the continued existence of arboviral infections outside of conventional peak months and support the necessity of continuous monitoring, even though seasonal comparisons and population-level transmission patterns cannot be established.

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