Parasitology and Vector Biology (PARAVEC) Laboratory, School of Public Health, University of Nevada, Las Vegas, NV, USA; Dr Richard Oxborough Consultancy, Las Vegas, NV, USA.
Parasitology and Vector Biology (PARAVEC) Laboratory, School of Public Health, University of Nevada, Las Vegas, NV, USA; Department of Environmental and Occupational Health, School of Public Health, University of Nevada, Las Vegas, NV, USA.
Lancet Planet Health. 2024 Oct;8(10):e804-e812. doi: 10.1016/S2542-5196(24)00172-4.
Mass distribution of insecticide-treated nets (ITNs) has been a key factor in reducing malaria cases and deaths in sub-Saharan Africa. A shortcoming has been the over-reliance on pyrethroid insecticides, with more than 2·13 billion pyrethroid ITNs (PY ITNs) distributed in the past two decades, leading to widespread pyrethroid resistance. Progressive changes are occurring, with increased deployment of more effective pyrethroid-chlorfenapyr (PY-CFP) or pyrethroid-piperonyl butoxide (PY-PBO) ITNs in areas of pyrethroid resistance. In 2023, PY-PBO ITNs accounted for 58% of all ITNs shipped to sub-Saharan Africa. PY-PBO and PY-CFP ITNs are 30-37% more expensive than standard PY ITNs, equating to an additional US$132-159 million required per year in sub-Saharan Africa to fund the shift to more effective ITNs. Several countries are withdrawing or scaling back indoor residual spraying (IRS) programmes to cover the shortfall, which is reflected by the number of structures sprayed by the US President's Malaria Initiative decreasing by 30% from 5·67 million (2021) to 3·96 million (2023). Benin, located in West Africa, is a prime example of a country that ceased IRS in 2021 after 14 years of annual spraying. Our economic evaluation indicates that IRS in Benin cost $3·50 per person protected per year, around five times more per person protected per year compared with PY-PBO ($0·73) or PY-CFP ITNs ($0·76). Although costly to implement, a major advantage of IRS is the portfolio of at least three chemical classes for prospective resistance management. With loss of synergy to PBO developing rapidly, there is the danger of over-reliance on PY-CFP ITNs. As gains in global malaria control continue to reverse each year, current WHO projections estimate that key 2030 malaria incidence milestones will be missed by a staggering 89%. This Personal View explores contemporary malaria vector control trends in sub-Saharan Africa and cost implications for improved disease control and resistance management.
大规模分发经杀虫剂处理的蚊帐（ITN）一直是减少撒哈拉以南非洲疟疾病例和死亡的关键因素。一个不足之处是过度依赖拟除虫菊酯杀虫剂，在过去二十年中分发了超过 21.3 亿片拟除虫菊酯 ITN（PY ITN），导致广泛的拟除虫菊酯抗药性。正在发生渐进式变化，在拟除虫菊酯抗性地区增加部署更有效的拟除虫菊酯-氯菊酯（PY-CFP）或拟除虫菊酯-胡椒基丁醚（PY-PBO）ITN。2023 年，PY-PBO ITN 占运往撒哈拉以南非洲的所有 ITN 的 58%。PY-PBO 和 PY-CFP ITN 比标准 PY ITN 贵 30-37%，这意味着撒哈拉以南非洲每年需要额外 1.32 亿至 1.59 亿美元来为转向更有效的 ITN 提供资金。一些国家正在撤回或缩减室内残留喷洒（IRS）计划以弥补这一不足，这反映出美国总统疟疾倡议喷洒的建筑物数量从 2021 年的 567 万（2021 年）减少到 2023 年的 396 万（2023 年）。贝宁位于西非，是一个在经过 14 年的年度喷洒后于 2021 年停止 IRS 的国家的典型例子。我们的经济评估表明，贝宁的 IRS 成本为每人每年保护费用 3.50 美元，是 PY-PBO（0.73 美元）或 PY-CFP ITN（0.76 美元）的每人每年保护费用的五倍左右。尽管实施成本高昂，但 IRS 的一个主要优势是至少有三种化学类别可供潜在的抗药性管理。随着对 PBO 的协同作用迅速丧失，有过度依赖 PY-CFP ITN 的危险。随着全球疟疾控制工作的持续进展每年都在逆转，目前的世卫组织预测估计，到 2030 年，关键的疟疾发病率里程碑将令人震惊地错过 89%。本文探讨了撒哈拉以南非洲当代疟疾媒介控制趋势以及改善疾病控制和抗药性管理的成本影响。
