Spatial- Temporal Spread of Dengue in Delhi: An Empirical Analysis

Abstract

Background & objectives: The epidemiology of dengue in Delhi is changing over the years and is now making it an endemic disease. It is not only rising but is slowly becoming more severe and spreading much faster than before. Within this perspective, this paper aims to map the distribution and intensity of dengue spread in Delhi on a fine spatial scale for the last decade to build an early warning system for the future. Methods: For this paper, the study followed a methodology that combined dengue data with suitable statistical approaches to find their spatial and temporal spread of dengue over Delhi. For this, primary data on dengue in Delhi was collected from 2009 to 2020 from the South Delhi Municipal Corporation (SDMC). GIS and compiled data were used to map the spatial distribution of Dengue occurrences at the Zonal and ward level. Dengue intensity indices were developed to identify the dengue hotspots and enable localised actions to manage dengue. A time-series analysis enabled understanding of dengue trends in SDMC and carrying out vulnerability assessments to develop a more targeted approach to manage dengue at the local level. Interviews with the select SDMC official using open-ended questions were used to identify the key challenges and issues in the management of dengue in Delhi. Results: Dengue is hyper endemic in the region and shows its presence throughout the year. Dengue is hyper endemic in the city and shows its presence throughout the year, with peaks observed from September to November. The trends in dengue indicate that the city has very rapidly come into the grip of the dengue and the post-monsoon periods observe high incidence rates, with cooler months also experiencing dengue cases. The dengue vector is fast spreading into the areas where it was not present before, which indicates that the dengue vector is adapting to the local environment and soon becomes a perennial feature in the city. We also observe clusters where the dengue is endemic and calls for a targeted measure. Interpretation & conclusion: Dengue in Delhi is perennial now, with peaks observed during the months from September- November. The trend in dengue indicates that the city has very rapidly come into the grip of the dengue, and the post-monsoon periods observe high incidence rates. The dengue vector is fast spreading into the areas where it was not present before. This indicates that dengue is adapting to the local environment and soon will become a perennial feature in the city and calls for a targeted measure.