Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore.
Environmental Health Institute, National Environmental Agency, Singapore.
PLoS Negl Trop Dis. 2023 Feb 2;17(2):e0011075. doi: 10.1371/journal.pntd.0011075. eCollection 2023 Feb.
Aedes aegypti abundance in residential estates is hypothesized to contribute to localised outbreaks of dengue in Singapore. Knowing the factors in the urban environment underlying high Ae. aegypti abundance could guide intervention efforts to reduce Ae. aegypti breeding and the incidence of dengue. In this study, objective data on Ae. aegypti abundance in public apartment blocks estimated by Singapore's nationally representative Gravitrap surveillance system was obtained from the National Environmental Agency. Low and high abundance status public apartment blocks were classified based on the Gravitrap Aegypti Index, corresponding to the lowest and highest quartiles respectively. An environmental case-control study was conducted, wherein a blinded assessment of urban features hypothesised to form breeding habitats was conducted in 50 randomly sampled public apartment blocks with low and high abundance statuses each. Logistic regression was performed to identify features that correlated with abundance status. A multivariable logistic model was created to determine key urban features found in corridors and void decks which were predictive of the Ae. aegypti abundance status of the public apartment block. At a statistical level of significance of 0.20, the presence of gully traps [Odds Ratio (OR): 1.34, 95% Confidence Interval (CI): 1.10, 1.66], age of the public apartment block [OR: 2.23, 95% CI: 1.48, 3.60], housing price [OR: 0.33, 95% CI: 0.16, 0.61] and corridor cleanliness [OR: 0.67, 95% CI: 0.40, 1.07] were identified as important predictors of abundance status. To reduce Ae. aegypti abundance around public apartment blocks and potential onward dengue transmission, gully traps could be remodelled or replaced by other drainage types. Routine inspections of Ae. aegypti breeding should be targeted at older and low-income neighbourhoods. Campaigns for cleaner corridors should be promoted.
埃及伊蚊在住宅区的数量被认为是导致新加坡局部登革热爆发的原因之一。了解城市环境中导致埃及伊蚊数量过多的因素，可以指导干预措施的实施，减少埃及伊蚊的滋生和登革热的发生。在这项研究中，从国家环境局获得了新加坡全国代表性 Gravitrap 监测系统估计的公共公寓楼中埃及伊蚊数量的客观数据。根据 Gravitrap Aegypti Index，将低丰度和高丰度公共公寓楼分别分类为丰度最低和最高的四分位数。进行了一项环境病例对照研究，在低丰度和高丰度的 50 个随机抽样的公共公寓楼中，对假设形成滋生地的城市特征进行了盲法评估。进行了逻辑回归，以确定与丰度状态相关的特征。创建了一个多变量逻辑模型，以确定在走廊和空旷甲板中发现的与埃及伊蚊丰度状态相关的关键城市特征。在统计学显著性水平为 0.20 时，存在沟渠陷阱[优势比（OR）：1.34，95%置信区间（CI）：1.10，1.66]、公共公寓楼的年龄[OR：2.23，95%CI：1.48，3.60]、住房价格[OR：0.33，95%CI：0.16，0.61]和走廊清洁度[OR：0.67，95%CI：0.40，1.07]被确定为丰度状态的重要预测因子。为了减少公共公寓楼周围埃及伊蚊的数量和潜在的登革热传播，沟渠陷阱可以通过其他排水类型进行改造或更换。应针对较旧和低收入社区定期进行埃及伊蚊滋生检查。应促进走廊清洁运动。
