Suleiman Auwal Garba, Kareem Lateef, Obi Charles
Department of Community Medicine, College of Medical Sciences, Ahmadu Bello University Zaria, Kaduna State, Nigeria.
Nigeria Malaria Modelling Fellowship, Corona Management Systems, Jabi, Abuja, Nigeria.
Niger Med J. 2025 Jun 16;66(2):528-539. doi: 10.71480/nmj.v66i2.672. eCollection 2025 Mar-Apr.
Indoor Residual Spraying (IRS) is one of the two major strategies recommended by the World Health Organization for malaria vector control. Between 2012 and 2013, IRS was piloted in two Local Government Areas (LGAs) of Nassarawa State, North-central Nigeria. Uncertainties remain as to whether the intervention led to a decrease in the rate of malaria transmission or not.
A simple SIRS model was used to generate a system of ordinary differential equations. The solutions of the model, obtained through Euler's method, were adapted to malaria surveillance data obtained from one of the interventions LGAs to estimate model parameters. The rate of malaria transmission, obtained from the intervention LGA, was compared with the one obtained from a carefully selected control LGA to ascertain the effect of IRS on malaria transmission, assuming other model parameters remained constant.
The results showed a good fit of surveillance data to the numerical solutions of the model. The estimated rate of malaria transmission in the intervention LGA was lower than the rate estimated in the non-intervention LGA, even though the difference was marginal (0.95 versus 1.05). Over two years, IRS activities reduced the rate of malaria transmission in the intervention LGA by 10%. The modest decrease was attributed to the way IRS was implemented and the uncertainties associated with using routine surveillance data in Nigeria.
Future IRS interventions should consider the effect of spray frequency on disease transmission and adopt a robust data collection strategy that will support proper monitoring and evaluation.
室内滞留喷洒（IRS）是世界卫生组织推荐的用于疟疾媒介控制的两大主要策略之一。2012年至2013年期间，在尼日利亚中北部纳萨拉瓦州的两个地方政府辖区（LGAs）进行了室内滞留喷洒试点。关于该干预措施是否导致疟疾传播率下降仍存在不确定性。
使用一个简单的易感-感染-康复-易感（SIRS）模型生成常微分方程组。通过欧拉方法获得的模型解被应用于从其中一个干预辖区获得的疟疾监测数据，以估计模型参数。将从干预辖区获得的疟疾传播率与从精心挑选的对照辖区获得的传播率进行比较，以确定室内滞留喷洒对疟疾传播的影响，假设其他模型参数保持不变。
结果表明监测数据与模型的数值解拟合良好。干预辖区估计的疟疾传播率低于非干预辖区估计的传播率，尽管差异很小（分别为0.95和1.05）。在两年时间里，室内滞留喷洒活动使干预辖区的疟疾传播率降低了10%。这种适度的下降归因于室内滞留喷洒的实施方式以及在尼日利亚使用常规监测数据所存在的不确定性。
未来的室内滞留喷洒干预措施应考虑喷洒频率对疾病传播的影响，并采用强有力的数据收集策略，以支持适当的监测和评估。
