First Outbreak of Dengue in Jorhat District of Assam

Introduction: Dengue Virus (DENV) infection is an important human arboviral infection. Though it is endemic in several parts of India. there has been no reported outbreak from Jorhat district of Assam, India. Aim: To present a comprehensive picture of the first outbreak of dengue fever that occurred in Jorhat (Assam, India) and its adjoining districts from July to December 2016. Materials and Methods: Serum samples from 289 clinically suspected cases of dengue fever were sent to Microbiology laboratory of Jorhat Medical College and hospital for serological confirmation of the diagnosis. All the samples were tested for DENV specific IgM antibodies and DENV-Non Structural protein 1 Antigen (NS1Ag) by ELISA. Results: Out of the 289 clinically suspected cases of dengue, 114 (39.45%) were positive for DENV infection. Amongst the seropositive cases, NS1Ag was positive in 80 (27.7%) and IgM antibody was positive in 72 (24.9%) cases. Both NS1Ag and IgM antibody were positive in 38 (13.1%) cases. Adults (n=109; 95.61 %) are more commonly affected than children (n=5; 4.39%). Male preponderance was noticed with a male:female ratio of 2.8:1. The maximum number of positive cases was reported in September (n=35; 30.71%) and occurred equally in rural (n=46; 40.4%) and urban areas (n=68; 59.6%). Fever was the most common presenting symptom followed by headache. Conclusion: Involvement of mainly the young adult population, male predominance and presence of rural dengue cases was seen during the outbreak. Majority of the cases presented with dengue fever without severe manifestations. Vector control measures and increased public awareness is the need of the hour to prevent further spread and complications of the disease in subsequent years.