Davis Kelly M, Worku Amha, Balkew Meshesha, Mumba Peter, Chibsa Sheleme, Tongren Jon Eric, Assefa Gudissa, Sisay Achamyelesh, Teshome Dawit, Tegegne Banchamlak, Worku Mastewal, Yimer Mulat, Yewhalaw Delenasaw, Yoshimizu Melissa, Zohdy Sarah, Swamidoss Isabel, Mapp Carla, Hwang Jimee, Inouye Wendy, Seyoum Aklilu, Flatley Cecilia, Hilton Emily R, Dengela Dereje, Burnett Sarah M
PMI Evolve Project, PATH, Washington, District of Columbia, USA
PMI Evolve Project, Abt Global, Addis Ababa, Ethiopia.
BMJ Glob Health. 2025 Jan 29;10(1):e016617. doi: 10.1136/bmjgh-2024-016617.
National malaria programmes must weigh the relative benefits of different vector control and elimination tools to prioritise resource allocation with the greatest impact. This study assesses the epidemiological and entomological impacts of piperonyl butoxide insecticide-treated nets (PBO ITN-only arm) compared with the combination of two annual non-pyrethroid indoor residual spraying (IRS) campaigns and standard pyrethroid ITNs (IRS+Standard Pyrethroid ITN arm) in the Amhara region of Ethiopia.
An open-label, stratified block-cluster randomised trial was designed to compare the impacts of the two intervention arms. ITN distribution took place from June to July 2021. IRS campaigns took place from June to July 2021 and again in June 2022. Confirmed malaria cases reported during the high transmission season (September to December) were compared in the 2 years before (2019 and 2020) vs the 2 years after (2021 and 2022) the 2021 campaigns. The difference in s.l. vector density per trap and indoor resting density (IRD) was assessed between the two arms during the high transmission seasons 2 years after the 2021 campaigns.
Estimated malaria cases decreased significantly by 53.6% in the postintervention period compared with preintervention in the IRS+Standard Pyrethroid ITN arm (95% CI -72.9%, -29.8%) and by 55.9% in the PBO ITN arm (95% CI -73.0%, -32.5%), with no significant difference between these two arms (95% CI -30.9%, 24.0%). From the first to the second season postintervention, cases decreased non-significantly in the IRS+Standard Pyrethroid ITN arm (incidence rate ratio (IRR) 0.94; 95% CI 0.66, 1.47) but increased significantly in the PBO ITN arm (IRR 1.98; 95% CI 1.49, 2.67). Postintervention vector density and IRD were not found to be significantly different between intervention arms in either 2021 (vector density: IRR 0.78; 95% CI 0.47, 1.31; IRD: IRR 0.80; 95% CI 0.37, 1.75) or 2022 (vector density: IRR 1.27; 95% CI 0.75, 2.12; IRD: IRR 1.02; 95% CI 0.45, 2.28).
These findings suggest a positive impact of non-pyrethroid IRS deployed annually alongside standard pyrethroid ITNs in a setting of confirmed pyrethroid resistance. While an overall positive impact of PBO ITNs was detected, a waning impact of the nets 2 years postdistribution was observed.
国家疟疾防治项目必须权衡不同病媒控制和消除工具的相对益处，以便优先分配资源并产生最大影响。本研究评估了在埃塞俄比亚阿姆哈拉地区，与每年两次非拟除虫菊酯类室内滞留喷洒（IRS）运动和标准拟除虫菊酯类长效驱虫蚊帐（IRS+标准拟除虫菊酯类长效驱虫蚊帐组）相结合相比，胡椒基丁醚杀虫剂处理蚊帐（仅含PBO长效驱虫蚊帐组）的流行病学和昆虫学影响。
设计了一项开放标签、分层整群随机试验，以比较两个干预组的影响。长效驱虫蚊帐于2021年6月至7月分发。IRS运动于2021年6月至7月进行，并于2022年6月再次开展。比较了2021年运动前两年（2019年和2020年）与运动后两年（2021年和2022年）高传播季节（9月至12月）报告的确诊疟疾病例。在2021年运动后两年的高传播季节，评估了两组之间每个诱捕器的按蚊属病媒密度和室内栖息密度（IRD）差异。
与干预前相比，IRS+标准拟除虫菊酯类长效驱虫蚊帐组干预后期估计疟疾病例显著减少53.6%（95%CI -72.9%，-29.8%），PBO长效驱虫蚊帐组减少55.9%（95%CI -73.0%，-32.5%），两组之间无显著差异（95%CI -30.9%，24.0%）。从干预后的第一季到第二季，IRS+标准拟除虫菊酯类长效驱虫蚊帐组病例减少不显著（发病率比（IRR）0.94；95%CI 0.66，1.47），而PBO长效驱虫蚊帐组病例显著增加（IRR 1.98；95%CI 1.49，2.67）。在2021年（病媒密度：IRR 0.78；95%CI 0.47，1.31；IRD：IRR 0.80；95%CI 0.37，1.75）或2022年（病媒密度：IRR 1.27；95%CI 0.75，2.12；IRD：IRR 1.02；95%CI 0.45，2.28），干预组之间干预后的病媒密度和IRD均无显著差异。
这些发现表明，在已确认存在拟除虫菊酯抗性的情况下，每年与标准拟除虫菊酯类长效驱虫蚊帐一起部署非拟除虫菊酯类IRS具有积极影响。虽然检测到PBO长效驱虫蚊帐总体具有积极影响，但在分发两年后观察到蚊帐的影响逐渐减弱。
