Hennessee Ian, Mutabazi Alphonse, Munyakanage Dunia, Kabera Michee, Mbituyumuremyi Aimable, Lucchi Naomi, Kirby Miles A, Waller Lance A, Clasen Thomas F, Kitron Uriel, Hakizimana Emmanuel
Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia.
Malaria and other Parasitic Diseases Division, Rwanda Biomedical Centre, Ministry of Health, Kigali, Rwanda.
Am J Trop Med Hyg. 2024 Oct 29;112(1):56-65. doi: 10.4269/ajtmh.23-0881. Print 2025 Jan 8.
Rwanda achieved unprecedented malaria control gains from 2000 to 2010, but cases increased 20-fold between 2011 and 2017. Vector control challenges and environmental changes were noted as potential explanations, but no studies have investigated causes of the resurgence or identified which vector species drove transmission. We conducted a retrospective study in four sites in eastern Rwanda that conducted monthly entomological surveillance and outpatient malaria care. We compared sporozoite rates, human blood index (HBI), and relative abundance of the primary vectors, Anopheles gambiae and Anopheles arabiensis, from 2017 to 2020. We then modeled the effects of vector control interventions, insecticide resistance, and temperature changes on species composition and reported malaria incidence. Sporozoite rates were 28 times higher and HBI was four times higher in An. gambiae compared with An. arabiensis. Insecticide-treated bed nets, first distributed nationally in 2010, were associated with decreased An. gambiae relative abundance. However, increased pyrethroid resistance was associated with increased An. gambiae relative abundance and malaria incidence. Epidemic malaria peaks corresponded to periods of model-predicted An. gambiae re-emergence, and increased regional air temperatures during the period were further associated with increased malaria incidence. Indoor residual spraying (IRS), implemented with non-pyrethroid insecticides later in the period, was associated with 86% reductions in An. gambiae relative abundance and 75% reductions in malaria incidence. These findings suggest that increased pyrethroid resistance and the re-emergence of An. gambiae were closely linked to the malaria resurgence in eastern Rwanda. Non-pyrethroid IRS or other control measures that effectively target An. gambiae may help prevent future resurgences.
2000年至2010年期间，卢旺达在疟疾防治方面取得了前所未有的进展，但在2011年至2017年期间，疟疾病例增加了20倍。媒介控制挑战和环境变化被认为是可能的原因，但尚无研究调查疟疾卷土重来的原因，也未确定是哪种媒介物种导致了传播。我们在卢旺达东部的四个地点进行了一项回顾性研究，这些地点每月进行昆虫学监测和门诊疟疾护理。我们比较了2017年至2020年期间主要媒介冈比亚按蚊和阿拉伯按蚊的子孢子率、人类血液指数（HBI）以及相对丰度。然后，我们模拟了媒介控制干预措施、杀虫剂抗性和温度变化对物种组成的影响，并报告了疟疾发病率。冈比亚按蚊的子孢子率比阿拉伯按蚊高28倍，HBI高4倍。2010年首次在全国范围内分发的经杀虫剂处理的蚊帐与冈比亚按蚊相对丰度的降低有关。然而，拟除虫菊酯抗性的增加与冈比亚按蚊相对丰度和疟疾发病率的增加有关。疟疾流行高峰与模型预测的冈比亚按蚊再次出现的时期相对应，该时期区域气温升高与疟疾发病率增加进一步相关。该时期后期使用非拟除虫菊酯杀虫剂实施的室内滞留喷洒（IRS）与冈比亚按蚊相对丰度降低86%和疟疾发病率降低75%有关。这些发现表明，拟除虫菊酯抗性的增加和冈比亚按蚊的再次出现与卢旺达东部疟疾的卷土重来密切相关。有效针对冈比亚按蚊的非拟除虫菊酯IRS或其他控制措施可能有助于预防未来的疫情复发。
