Rapid response and epidemic preparedness led to control of dengue outbreak in rural areas of Namakkal district, Tamilnadu, India, 2017 and 2018.

Abstract

Background: Tamilnadu state, India reported 11,744 dengue cases in 2017. Dengue cases started increasing in rural parts of Namakkal district, Tamilnadu in 2017. Following the epidemic, public health department took control measures. We analysed the dengue epidemic to measure the impact of control measures. Methods and materials: We did a quasi-experimental study. We included rural residents of Namakkal district in the study. We defined a confirmed case of dengue as any patient with fever for more than 2 days and positive for IgM antibody or NS1 antigen by ELISA method. Rapid response team (RRT) did active surveillance, collected clinical samples and sent to district public health laboratory. RRT conducted special medical camps, chlorinated all sources of stored water and did mass cleaning of affected areas. RRT conducted anti-larval works and fogging activities in affected areas. They also created awareness among community through meetings. We collected line list of confirmed dengue cases from district public health laboratory and identified private laboratories for the year 2017. We included cases which were cross notified from other districts. We collected dengue linelist for 2018 for comparing with baseline. We calculated proportions for attack rate per 1 million population in all rural health blocks of Namakkal. We calculated paired t test for comparing mean dengue cases reported in each health blocks in 2017 and 2018 to measure the effect of control measures. Results: There were 15 rural health blocks in Namakkal district. There were 982 cases(Attack rate = 696/million) in 2017. Median age of cases were 17 years (Range: 4 months to 80 years). Attack rate among females was 685/million (471/686718) and among males was 706/ million(511/723313) in 2017. Dengue cases decreased to 78 cases (Attack rate = 55/million) in 2018. Attack rate was 48/million among females (n = 33) and 62/million among males (n = 45). Outbreak was controlled with decreased incidence of cases in all 15 blocks in 2018. (Mean difference was 60, with standard deviation of 28). Paired t test was significant at p < 0.05 (t = 8.3). Conclusion: Dengue epidemic was effectively controlled in rural areas of Namakkal by rapid response team. We recommend to implement similar control measures in other areas with dengue epidemic.