Dhewantara Pandji Wibawa, Marina Rina, Puspita Tities, Ariati Yusniar, Purwanto Edy, Hananto Miko, Hu Wenbiao, Soares Magalhaes Ricardo J
Pangandaran Unit for Health Research and Development, National Institute of Health Research and Development (NIHRD), Ministry of Health of Indonesia, West Java, 46396, Indonesia; UQ Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Gatton, QLD, 4343, Australia.
Center for Public Health Research and Development, National Institute of Health Research and Development (NIHRD), Ministry of Health of Indonesia, Jakarta, 10560, Indonesia.
Travel Med Infect Dis. 2019 Nov-Dec;32:101437. doi: 10.1016/j.tmaid.2019.06.008. Epub 2019 Jul 27.
Dengue fever control in the tropical island of Bali in Indonesia carries important significance both nationally and globally, as it is one of the most endemic islands in Indonesia and a worldwide popular travel destination. Despite its importance, the spatial and temporal heterogeneity in dengue risk and factors associated with its variation in risk across the island has not been not well explored. This study was aimed to analyze for the first time the geographical and temporal patterns of the incidence of dengue and to quantify the role of environmental and social factors on the spatial heterogeneity of dengue incidence in Bali.
We analyzed retrospective dengue notification data at the sub-district level (Kecamatan) from January 2012 to December 2017 which obtained from the Indonesian Ministry of Health. Seasonality in notified dengue incidence was assessed by seasonal trend decomposition analysis with Loess (STL) smoothing. Crude standardized morbidity rates (SMRs) of dengue were calculated. Moran's I and local indicators of spatial autocorrelation (LISA) analysis were employed to assess spatial clustering and high-risk areas over the period studied. Bayesian spatial and temporal conditional autoregressive (CAR) modeling was performed to quantify the effects of rainfall, temperature, elevation, and population density on the spatial distribution of risk of dengue in Bali.
Strong seasonality of dengue incidence was observed with most cases notified during January to May. Dengue incidence was spatially clustered during the period studied with high-risk kecamatans concentrated in the south of the island, but since 2014, the high-risk areas expanded toward the eastern part of the island. The best-fitted CAR model showed increased dengue risk in kecamatans with high total annual rainfall (relative risk (RR): 1.16 for each 1-mm increase in rainfall; 95% Credible interval (CrI): 1.03-1.31) and high population density (RR: 7.90 per 1000 people/sq.km increase; 95% CrI: 3.01-20.40). The RR of dengue was decreased in kecamatans with higher elevation (RR: 0.73 for each 1-m increase in elevation; 95% CrI: 0.55-0.98). No significant association was observed between dengue RR and year except in 2014, where the dengue RR was significantly lower (RR: 0.53; 95% CrI: 0.30-0.92) relative to 2012.
Dengue incidence was strongly seasonal and spatially clustered in Bali. High-risk areas were spread from kecamatans in Badung and Denpasar toward Karangasem and Klungkung. The spatial heterogeneity of dengue risk across Bali was influenced by rainfall, elevation, and population density. Surveillance and targeted intervention strategies should be prioritized in the high-risk kecamatans identified in this study to better control dengue transmission in this most touristic island in Indonesia. Local health authorities should recommend travelers to use personal protective measures, especially during the peak epidemic period, before visiting Bali.
印度尼西亚热带岛屿巴厘岛的登革热防控在国内和全球都具有重要意义，因为它是印度尼西亚登革热流行最严重的岛屿之一，也是全球热门旅游目的地。尽管其重要性不言而喻，但登革热风险的时空异质性以及全岛风险变化相关因素尚未得到充分研究。本研究旨在首次分析登革热发病率的地理和时间模式，并量化环境和社会因素对巴厘岛登革热发病率空间异质性的作用。
我们分析了2012年1月至2017年12月从印度尼西亚卫生部获取的分区（ kecamatan）层面的回顾性登革热通报数据。通过局部加权回归散点平滑法（STL）季节性趋势分解分析评估通报的登革热发病率的季节性。计算登革热的粗标准化发病率（SMR）。采用莫兰指数（Moran's I）和局部空间自相关指标（LISA）分析来评估研究期间的空间聚集情况和高风险区域。进行贝叶斯时空条件自回归（CAR）建模，以量化降雨、温度、海拔和人口密度对巴厘岛登革热风险空间分布的影响。
观察到登革热发病率有很强的季节性，大多数病例在1月至5月通报。在研究期间，登革热发病率在空间上呈聚集状态，高风险的 kecamatan集中在岛屿南部，但自2014年以来，高风险区域向岛屿东部扩展。拟合效果最佳的CAR模型显示，年总降雨量高的 kecamatan登革热风险增加（相对风险（RR）：降雨量每增加1毫米为1.16；95%可信区间（CrI）：1.03 - 1.31），人口密度高的地区风险也增加（RR：每平方公里每增加1000人风险为7.90；95% CrI：3.01 - 20.40）。海拔较高的 kecamatan登革热RR降低（RR：海拔每增加1米为0.73；95% CrI：0.55 - 0.98）。除2014年外，未观察到登革热RR与年份之间存在显著关联，2014年登革热RR相对于2012年显著降低（RR：0.53；95% CrI：0.30 - 0.92）。
巴厘岛的登革热发病率具有很强的季节性且在空间上呈聚集状态。高风险区域从巴东和登巴萨的 kecamatan扩展到卡朗阿森和克隆孔。巴厘岛登革热风险的空间异质性受降雨、海拔和人口密度影响。应优先在本研究确定的高风险 kecamatan进行监测和有针对性地干预策略，以更好地控制印度尼西亚这个旅游胜地岛屿的登革热传播。当地卫生当局应建议旅行者在访问巴厘岛之前采取个人防护措施，尤其是在疫情高峰期。
