Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America.
Fortaleza Municipal Health Secretariat (SMS-Fortaleza), Fortaleza, Ceará, Brazil.
PLoS Negl Trop Dis. 2018 Dec 3;12(12):e0006990. doi: 10.1371/journal.pntd.0006990. eCollection 2018 Dec.
After being eliminated during the 1950s, dengue reemerged in Brazil in the 1980s. Since then, incidence of the disease has increased, as serotypes move within and between cities. The co-circulation of multiple serotypes contributes to cycles of epidemic and interepidemic years, and a seasonal pattern of transmission is observed annually. Little is known regarding possible differences in the epidemiology of dengue under epidemic and interepidemic scenarios. This study addresses this gap and aims to assess the epidemiological characteristics and determinants of epidemic and interepidemic dengue transmission, utilizing data from the 5th largest city in Brazil (Fortaleza), at fine spatial and temporal scales.
METHODS/PRINCIPAL FINDINGS: Longitudinal models of monthly rates of confirmed dengue cases were used to estimate the differential contribution of contextual factors to dengue transmission in Fortaleza between 2011 and 2015. Models were stratified by annual climatological schedules and periods of interepidemic and epidemic transmission, controlling for social, economic, structural, entomological, and environmental factors. Results revealed distinct seasonal patterns between interepidemic and epidemic years, with persistent transmission after June in interepidemic years. Dengue was strongly associated with violence across strata, and with poverty and irregular garbage collection during periods of low transmission, but not with other indicators of public service provision or structural deprivation. Scrapyards and sites associated with tire storage were linked to incidence differentially between seasons, with the strongest associations during transitional precipitation periods. Hierarchical clustering analysis suggests that the dengue burden concentrates in the southern periphery of the city, particularly during periods of minimal transmission.
CONCLUSIONS/SIGNIFICANCE: Our findings have direct programmatic implications. Vector control operations must be sustained after June even in non-epidemic years. More specifically, scrapyards and sites associated with tires (strongly associated with incidence during periods of minimal transmission), require sustained entomological surveillance, particularly during interepidemic intervals and in the urban periphery. Intersectoral collaborations that address urban violence are critical for facilitating the regular activities of vector control agents.
20 世纪 50 年代，登革热在巴西被消灭，20 世纪 80 年代又重新出现。此后，由于血清型在城市内部和城市之间的传播，疾病的发病率不断上升。多种血清型的共同传播导致了流行年和间发年的循环，每年都会观察到季节性传播模式。关于流行和间发情况下登革热的流行病学可能存在差异，人们对此知之甚少。本研究旨在利用巴西第五大城市（福塔莱萨）的精细时空数据，评估流行和间发登革热传播的流行病学特征和决定因素，以填补这一空白。
方法/主要发现：使用每月确诊登革热病例率的纵向模型，估计在 2011 年至 2015 年期间，福塔莱萨的背景因素对登革热传播的差异贡献。模型按年度气候时间表和流行和间发传播期分层，控制社会、经济、结构、昆虫学和环境因素。结果显示，流行年和间发年之间存在明显的季节性模式，间发年后 6 月仍有持续传播。登革热与各层暴力事件密切相关，与低传播期的贫困和不规则垃圾收集有关，但与其他公共服务提供或结构性剥夺指标无关。废品场和与轮胎储存有关的地点与季节之间的发病率存在差异，在过渡性降水期关联最强。层次聚类分析表明，登革热负担集中在城市的南部边缘，尤其是在传播最小的时期。
结论/意义：我们的研究结果具有直接的计划意义。即使在非流行年，也必须在 6 月后继续进行蚊虫控制行动。更具体地说，废品场和与轮胎有关的地点（与最低传播期的发病率密切相关）需要持续进行昆虫学监测，特别是在间发期和城市周边地区。解决城市暴力问题的跨部门合作对于促进蚊虫控制人员的正常活动至关重要。
