The Effectiveness of Indoor Residual Spraying Program in Reducing Malaria Incidence in Mutasa District 2020 to 2022

Abstract

Malaria remains a critical public health issue, and while control measures have evolved, particularly with the use of Indoor Residual Spraying (IRS), the disease’s persistence calls for continuous assessment of these interventions. This study, conducted in the high malaria transmission zone of Mutasa District from 2020 to 2022, aimed to evaluate the impact of IRS on the reduction of malaria cases. Employing a quasi-experimental design, the research juxtaposed pre-test and post-test data within IRS-implemented areas against those without such interventions. The investigation hinged on the analysis of health information systems and household survey data, processed through stratified random sampling, to measure IRS’s reach and execution quality. The pivotal metric was the variance in malaria incidence rates between areas subjected to IRS and those that were not, considering the elements that affect IRS deployment. The findings revealed a marked decrease in malaria incidence within the areas treated with IRS, accompanied by significant enhancements in both the extent of coverage and the quality of the spraying program. In 2020 IRS-treated areas had a mean incidence rate of 240.60 with a standard deviation of 362.387. Non-IRS-treated areas had a mean incidence rate of 68.44 with a standard deviation of 61.67. In 2021 IRS-treated areas had a mean incidence rate of 39.67 with a standard deviation of 54.697. Non-IRS-treated areas had a mean incidence rate of 9.75 with a standard deviation of 8.226. In 2022 IRS-treated areas had a mean incidence rate of 11.17 with a standard deviation of 13.799. Non-IRS-treated areas had a mean incidence rate of 4.38 with a standard deviation of 3.074. The data indicates a decrease in the annual malaria incidence rate over the three years in both IRS-treated and non-IRS-treated areas. The IRS-treated areas consistently show higher mean incidence rates compared to non-IRS-treated areas for each year. These results affirm the efficacy of IRS in curtailing malaria incidence, underscoring the critical need for extensive coverage and stringent quality control in the successful management of malaria. The study’s conclusions advocate for the sustained and scaled-up application of IRS, alongside a commitment to maintaining high operational standards, to ensure continued progress in malaria control efforts.