Evaluating the effectiveness of different intervention measures for a dengue outbreak in Hangzhou based on a dynamic...

On the basis of 2017 dengue fever outbreak data from Shangcheng District, this study developed a dynamic transmission model to analyze the epidemiological characteristics of dengue fever at a district scale, quantitatively evaluated the effectiveness of different intervention measures, and provided evidence-based support for optimizing outbreak control strategies.

The outbreak data were obtained from the China Information Network System of Disease Prevention and Control. Some transmission parameters were initially estimated via Berkeley Madonna 8.3.18 software. An SEIAR epidemic model incorporating host-vector bidirectional transmission dynamics was established to evaluate the effectiveness of case isolation, health education, and vector control.

With no intervention, the outbreak would last 225 days, resulting in 8420 cumulative cases, which were both significantly higher than the actual outbreak data (CC = 278 cases, DO = 79 days). Case isolation was the least effective intervention for epidemic control, reducing the cumulative number of cases by only about 71% compared to the estimated incidence without intervention. Vector control was the most effective single intervention. Even a 5% daily vector density reduction intervention could reduce cumulative cases by about 97% and shorten the outbreak duration to 87 days. Increasing the coverage rate and the behavior formation rate of health education could also effectively reduce the number of cumulative cases and shorten the duration of an outbreak. The combined strategy of low-frequency mosquito control (every 3 days) and health education (60% coverage, 50% behavior adoption) and 100% case isolation performed only slightly worse than sustained low-intensity mosquito control alone. However, they were both relatively close to the actual prevention and control effectiveness observed in 2017.

For dengue control in high-density urban areas, we suggested a three-tiered synergistic prevention system: a foundation tier of strict case isolation coupled with intelligent monitoring and early-warning systems; a core tier of sustained high-intensity mosquito control to rapidly suppress vector density during the early epidemic stage; and an optimization tier integrated pulsed mosquito control, health education, and case isolation, thereby addressing the limitations of single interventions and minimizing costs.