Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
Africa University, Mutare, Zimbabwe.
Am J Trop Med Hyg. 2024 May 21;111(1):35-42. doi: 10.4269/ajtmh.23-0466. Print 2024 Jul 3.
Cross-border human population movement contributes to malaria transmission in border regions, impeding national elimination. However, its impact in low-to-moderate transmission settings is not well characterized. This community-based study in Mutasa District, Zimbabwe, estimated the association of parasite prevalence with self-reported overnight travel to Mozambique and household distance to the border from 2012-2020. A fully adjusted Poisson regression model with robust variance estimation was fit using active surveillance data. The population attributable fraction of parasite prevalence from overnight travel was also estimated. The relative risk of testing positive for malaria by rapid diagnostic test declined 14% (prevalence ratio [PR] = 0.86, 95% CI = 0.81-0.92) per kilometer from the border up to 12 km away. Travel to Mozambique was associated with a 157% increased risk (PR = 2.57, 95% CI = 1.38-4.78), although only 5.8% of cases were attributable to overnight travel (95% CI = -1.1% to 12.7%), reflecting infrequent overnight trips (1.3% of visits). This study suggests that transmission in eastern Zimbabwe is driven by increasingly conducive social or environmental conditions approaching the border and low levels of importation from overnight travel. Although day trips to Mozambique during peak biting hours were not assessed, the contribution of such trips to ongoing transmission may be significant. Future malaria control efforts should prioritize high coverage of existing interventions and continued support for community health workers and health facilities at the border, which provide free case management.
跨境人口流动促进了边境地区的疟疾传播,阻碍了国家的消除工作。然而,在低至中度传播地区,其影响尚未得到充分描述。本项以社区为基础的研究在津巴布韦穆塔萨区进行,旨在评估 2012 年至 2020 年间,寄生虫流行率与向莫桑比克的夜间旅行和家庭距离边境的关系。使用主动监测数据,拟合了具有稳健方差估计的完全调整泊松回归模型。还估计了寄生虫流行率中因夜间旅行而导致的归因比例。距离边境每增加 1 公里,快速诊断检测呈疟疾病例的相对风险降低 14%(患病率比 [PR] = 0.86,95%CI = 0.81-0.92)。前往莫桑比克的旅行风险增加了 157%(PR = 2.57,95%CI = 1.38-4.78),尽管只有 5.8%的病例归因于夜间旅行(95%CI = -1.1%至 12.7%),这反映出夜间旅行频率较低(访问的 1.3%)。本研究表明,津巴布韦东部的传播是由接近边境的日益有利的社会或环境条件以及来自夜间旅行的低水平输入驱动的。虽然没有评估在高峰叮咬时间前往莫桑比克的一日游,但这些旅行对持续传播的贡献可能是重大的。未来的疟疾控制工作应优先考虑现有干预措施的高覆盖率,并继续支持边境地区的社区卫生工作者和卫生设施,这些设施提供免费的病例管理。