Epidemiological Insights into Dengue Infection with Preliminary Emphasis on Serotype Distribution and Risk Factors in Karbi Anglong,Assam: A Cross-Sectional Study

Abstract

Dengue is a viral illness primarily transmitted by Aedes aegypti and Aedes albopictus, which thrive in tropical and densely populated urban environments. Its rising global incidence has been linked to factors such as climate change, inadequate sanitation, and expanding urbanization. A dengue outbreak in Diphu, Assam, from 2022 to 2024 prompted this study, which aims to identify the circulating serotypes and assess associated risk factors. The study involved 7,805 symptomatic patients from Diphu Medical College and Integrated Disease Surveillance Program field visits. Patients with malaria or other viral infections were excluded. After obtaining informed consent, participants provided sociodemographic details and underwent NS1 antigen and IgM ELISA tests. RT-PCR was performed on all positive samples for dengue serotype identification. Among the suspected cases, 50.22% tested positive for dengue, of which 45.39% were acute and 4.83% were recent infections. Adults (56.12%), males (56.58%), tribal groups (56.37%), rural residents (50.88%), and individuals with lower education (50.0%) had higher infection rates. Preliminary investigation of 49 representative RT-PCR positive samples exhibited that DENV2 was the predominant serotype (57.1%), followed by DENV2&3 coinfections. Logistic regression showed increased risk associated with adult age, tribal ethnicity, rural residence, and coinfection, while higher literacy lowered the odds. The study highlights a high prevalence of dengue in Karbi Anglong and underscores the need for early diagnosis, community awareness, surveillance, and strengthened vector control measures to reduce the disease burden.