Effect of Piperonyl Butoxide (PBO) long lasting insecticide treated nets (llins) on malaria incidence and test positivity rate compared to standard llins after mass net campaign in Kenya, 2021

Abstract

Objective: This study aimed to compare the effectiveness of Piperonyl Butoxide (PBO) Long -Lasting Insecticidal Treated Nets (LLINs) and  standard LLINs on malaria incidence and Test Positivity Rate (TPR).

Design: This was a retrospective cross-sectional study using  routinely collected data on malaria incidence and test positivity rate in Kenya Health Information System (KHIS) from a county where PBO  LLINs and standard LLINs were distributed.

Setting: Malaria incidence and positivity rate data from Siaya and Busia counties where  standard LLINs and PBO LLINs were distributed respectively was extracted from KHIS. The two counties are within Lake endemic zone  with malaria prevalence at 19% and high intensity of insecticide resistance. Interventions: Deployment of PBO and standard LLINs.

Main  outcome measures: Malaria incidence and test positivity rate. Results: Malaria incidence decreased from 612.8 cases in 2020 to 590.5  cases in 2021 and TPR decreased from 54.6% in 2020 to 47.4% in 2021 after the distribution of standard LLINs. In Busia where PBO LLINs  were distributed, Malaria incidence increased from 436.9 cases in 2020 to 525.4 2021 after distribution due to increased blood  examination rate from 84 per 100 populations to 106.3 per 100 populations in 2021. Test positivity rate decreased from 48.3% in 2020 to  43.1% in 2021 after distribution of PBO.

Conclusion: The PBO LLINs were more effective than standard LLINs in reduction of malaria  incidence and test positivity rate in an area with high intensity of pyrethroid resistance.