Assessing health burden risk and control effect on dengue fever infection in the southern region of Taiwan

Cheng, Yi-Hsien; Lin, Yi-Jun; Chen, Szu-Chieh; You, Shu-Han; Chen, Wei-Yu; Hsieh, Nan-Hung; Yang, Ying-Fei; Liao, Chung-Min

Based on the epidemiological study in Taiwan, Hsu et al 44 indicated that people aged 60-69 years had a relatively higher prevalence rate of dengue fever than those in the other age 44 Besides the temperature dependency in epidemics and disease burden, this study also investigated the optimal control strategies by using the different combinations of the control measures that contain dengue outbreak targeting different aspects of either host and/or vector populations. In this study, four commonly used control measures were combined for modeling the control effectiveness in different seasons. Repellent spray (R) alone by hosts can achieve the higher control effectiveness of 71% whereas the other interventions -pesticide spray (S), water container clean-up (C), and Wolbachia infection (W) can only achieve control effectiveness of 21%, 12%, and 10%, respectively, in all seasons. Therefore, the implication for repellent spray could be expedited in an epidemic setting in the future as the primary preventive response beginning in early summer to contain further dengue outbreaks in the following seasons. Although other interventions, due to lower efficacies compared with that of repellent spray, could serve as complemented and combinative interventions to prevent and contain dengue outbreaks. Repellent spray alone by hosts is the highest control effectiveness. In considering the repellent product as a control measure against mosquito vectors, it is important to understand specific-repellent efficacy on the length of use 45, 46 and mosquito species. 47 Two essential oils (Melaleuca leucadendron and Callistemon citrinus) have been demonstrated to have higher adulticidal activity with 8 hours of exposure than with 5 hours in A. aegypti and Culex quinquefasciatus. 45 Soonwera et al 47 found that Cymbopogon citratus oil exhibited repellent activity with 98.7% protection from bites from female A. aegypti and 99.8% from female C. quinquefasciatus. Therefore, future research should investigate the length of use and specific mosquito species to develop repellent spray formulations in the control of dengue vectors.