Urban dengue surveillance over sixteen years: Integration, trend analysis and participation of private medical sector

Abstract

Purpose: The increasing urbanisation and evolution of dengue vector offers favorable grounds for dengue. In absence of effective vaccine and therapeutic interventions, surveillance and reporting becomes mainstay for dengue management. Methods: Extensive efforts integrated various components (vector, human case, laboratory, environment and virus) of dengue surveillance with existing vector-borne disease surveillance in a large municipal corporation of western India. Approximately 80% private sector was involved to enhance and expand epidemiological picture of dengue transmission. Weekly entomological surveillance for immature and mature forms of Aedes mosquito was performed by trained team. Standardised sentinel hospital laboratories confirmed serological diagnosis. Virus serotype surveys and environmental indices were integrated later. Results: Between years 2000- 2016, total 24,506 clinically suspected and 3,515 confirmed cases were tested and reported respectively. After 2006, private sector contributed 10970 (40%) suspected and 971 (30%) confirmed cases. The adult vector density emerged as significantly correlated (r=0.67) to dengue cases. Low (<1) level of larval indices; House index (HI), Container's index (CI) and Breteau index (BI) supported dengue transmission. The virus serotype survey shows predominant DEN-2 strain. The quality controlled and detailed case information guided implementation of prevention and control measure. Conclusions: Integration of dengue surveillance components with special emphasis on private sector leads to better informed program managers and healthcare providers.