Abstract
Dengue is a notifiable disease in India since 1996, with an annual average of 20 018 laboratory confirmed cases reported between 2006 and 2012. However, the true magnitude of dengue burden is poorly understood. A study was conducted to estimate the true number of clinically diagnosed dengue cases in Madurai District, Tamil Nadu. A descriptive inventory was developed on healthcare facilities treating and/or testing and laboratories testing dengue. The hospitals were stratified by bed capacity and the laboratories by type of dengue tests performed. Numbers of dengue cases clinically diagnosed, tested and confirmed for the years 2009–2011 were obtained from the selected facilities and extrapolated to obtain a realistic estimate. Projected cases were compared with the officially reported numbers to highlight possible missing cases of dengue. The average projected number of clinically diagnosed dengue cases referred to laboratory for testing was 6334 whereas that of hospitalized confirmed dengue cases accounted for 2188. Ironically, for the same period, the average number of reported dengue cases for the district was 134 and for the 126 state. This gives an adjustment factor of 16.29 at the district level and 17.41 at the state