Malaria control using long-lasting insecticidal nets (LLINs) and indoor residual spraying of insecticide (IRS) has been associated with reduced transmission throughout Africa. However, the impact of transmission reduction on the age distribution of malaria cases remains unclear. Over a 10-year period (January 2009 to July 2018), outpatient surveillance data from four health facilities in Uganda were used to estimate the impact of control interventions on temporal changes in the age distribution of malaria cases using multinomial regression. Interventions included mass distribution of LLINs at all sites and IRS at two sites. Overall, 896,550 patient visits were included in the study; 211,632 aged < 5 years, 171,166 aged 5–15 years and 513,752 > 15 years. Over time, the age distribution of patients not suspected of malaria and those malaria negative either declined or remained the same across all sites. In contrast, the age distribution of suspected and confirmed malaria cases increased across all four sites. In the two LLINs-only sites, the proportion of malaria cases in < 5 years decreased from 31 to 16% and 35 to 25%, respectively. In the two sites receiving LLINs plus IRS, these proportions decreased from 58 to 30% and 64 to 47%, respectively. Similarly, in the LLINs-only sites, the proportion of malaria cases > 15 years increased from 40 to 61% and 29 to 39%, respectively. In the sites receiving LLINs plus IRS, these proportions increased from 19 to 44% and 18 to 31%, respectively. These findings demonstrate a shift in the burden of malaria from younger to older individuals following implementation of successful control interventions, which has important implications for malaria prevention, surveillance, case management and control strategies.

中文翻译：

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在乌干达四个地区成功实施控制干预措施之后，按年龄段划分的疟疾负担迅速变化

使用持久性杀虫网（LLIN）和室内残留喷洒杀虫剂（IRS）来控制疟疾与减少整个非洲的传播有关。但是，减少传播对疟疾病例年龄分布的影响尚不清楚。在10年期间（2009年1月至2018年7月），使用多项回归法，使用了乌干达四个卫生机构的门诊监测数据来估计控制干预措施对疟疾病例年龄分布的时间变化的影响。干预措施包括在所有地点大规模分配LLIN，在两个地点进行IRS。总体上，该研究包括896,550位患者就诊。211,632岁（小于5岁），171,166岁（5至15岁）和513,752（15岁以上）。随着时间的推移，在所有地点，未怀疑患有疟疾的患者和那些疟疾阴性的患者的年龄分布下降或保持不变。相反，在所有四个地点，可疑和确诊的疟疾病例的年龄分布都在增加。在仅LLIN的两个站点中，<5年内的疟疾病例比例分别从31％降至16％和35％至25％。在接受LLIN加IRS的两个站点中，这些比例分别从58％降至30％和64％降至47％。同样，在仅LLIN的地点，> 15年的疟疾病例比例分别从40％增至61％和29％增至39％。在接受LLIN加IRS的站点中，这些比例分别从19％增至44％和18％增至31％。