Travis Catherine Tamera, Argibay Hernán D, Pellizzaro Maysa, de Oliveira Daiana, Santana Roberta, Palma Fabiana Almerinda G, Lustosa Ricardo, Santana Juliet Oliveira, Souza Fábio Neves, Alzate López Yeimi Alexandra, Reis Mitermayer G, Ko Albert I, Diggle Peter J, Ribeiro Guilherme S, Begon Michael, Costa Federico, Khalil Hussein, Eyre Max T
Southern Nevada Health District, Las Vegas, Nevada, United States of America.
Federal University of Bahia, Collective Health Institute, Salvador, Bahia, Brazil.
PLoS Negl Trop Dis. 2025 Sep 5;19(9):e0013477. doi: 10.1371/journal.pntd.0013477. eCollection 2025 Sep.
Chikungunya virus (CHIKV) is an arbovirus with a significant global public health burden. Delineating the specific contributions of individual behaviour, household, natural and built environment to CHIKV transmission is important for reducing risk in urban informal settlements but challenging due to their heterogeneous environments. The aim of this study was to quantify variation in CHIKV seroprevalence between and within four urban communities in a large Brazilian city, and identify the respective contributions of individual, household, and environmental factors for seropositivity.
METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional serological survey was conducted in four low-income communities in Salvador, Brazil in 2018 to collect individual, household and CHIKV IgG serology data for 1318 participants. Fine-scale community mapping of high-risk environmental features and remotely sensed environmental data were used to improve characterisation of the microenvironment close to the household. We categorised risk factors into three domains - individual, household, and environmental and used binomial mixed-effect models to identify associations with CHIKV seropositivity. CHIKV seroprevalence was 4.8%, 6.1% and 4.3% in three communities and 22.6% in one community which had a distinct topographical profile. The only individual domain variable associated with seropositivity was male sex (OR 1.67, 95% CI 1.11 - 2.36), but several environmental variables, including living in a house on a steep hillside, at medium to high elevations, and with surface water nearby, were associated with higher seropositivity.
CONCLUSIONS/SIGNIFICANCE: Our findings indicate that CHIKV exposure risk can vary significantly between nearby communities and at fine spatial scales within communities and is likely to be driven more strongly by the availability of mosquito breeding sites rather than individual exposure patterns. They suggest that environmental deficiencies and topography, a proxy for several environmental processes including the degree of urbanisation and flooding risk, may play an important role in driving risk at both of these scales.
基孔肯雅病毒（CHIKV）是一种虫媒病毒，给全球公共卫生带来了重大负担。明确个体行为、家庭、自然环境和建筑环境对基孔肯雅病毒传播的具体影响，对于降低城市非正式住区的风险至关重要，但由于这些地区环境各异，这一工作颇具挑战性。本研究的目的是量化巴西一个大城市中四个城市社区之间及内部基孔肯雅病毒血清阳性率的差异，并确定个体、家庭和环境因素对血清阳性的各自影响。
方法/主要发现：2018年在巴西萨尔瓦多的四个低收入社区开展了一项横断面血清学调查，收集了1318名参与者的个体、家庭和基孔肯雅病毒IgG血清学数据。利用高风险环境特征的精细社区地图和遥感环境数据，以更好地描述家庭附近的微环境。我们将风险因素分为三个领域——个体、家庭和环境，并使用二项混合效应模型来确定与基孔肯雅病毒血清阳性的关联。三个社区的基孔肯雅病毒血清阳性率分别为4.8%、6.1%和4.3%，一个地形独特的社区血清阳性率为22.6%。与血清阳性相关的唯一个体领域变量是男性（比值比1.67，95%置信区间1.11 - 2.36），但包括居住在陡峭山坡上、中高海拔以及附近有地表水的房屋等几个环境变量与较高的血清阳性率相关。
结论/意义：我们的研究结果表明，基孔肯雅病毒暴露风险在附近社区之间以及社区内的精细空间尺度上可能存在显著差异，并且可能更多地受到蚊子繁殖场所的影响，而非个体暴露模式。研究结果表明，环境缺陷和地形（可作为包括城市化程度和洪水风险在内的多个环境过程的代表）可能在这两个尺度的风险驱动中发挥重要作用。
