author(s)
Amaechi AA, Iwunze JI, Ogu EM, Alisi GE, Awah P Amarachi, Nwabueze JU, Ogu O Ginikanwa, Uzoagba DC and Tony-Nze CP

abstract
Several preventive methods are currently in use; Insecticide Treated Nets (ITNs), prophalytic drugs (PD) and Indoor Residual Spray (IRS) including Environmental Sanitation (ES) and Health Education (HE). It has remain unclear which measure is the most effective for malaria prevention. We undertook a study to compare the efficacy of different interventions (single and combined) on human subjects and Anopheles mosquitoes between July 2023 and May 2024 in Intervention Cohorts (ICs) and non-intervention cohorts (NICs). Human blood samples aseptically collected were processed using standard procedures. Mosquitoes were caught in 25 households (10 mud and 15 bricks) from each community twice monthly with pyrethrium knockdown (PKD) between 7:00-10:00am from Single Intervention Cohorts (SICs) and combined intervention cohorts (CICs). They were morphologically identified, dissected and Infection rate of salivary glands were assessed for Plasmodium sporozoite Infections using standard protocols. Overall malaria prevalence 12.12% baseline (NICs) and SICs (9.50%) showed that malaria prevalence in NICs was 5times higher than prevalence in SICs (p<0.05). All intervention methods (ITN 4.59% > PD 5.71% >IRS 7.14%) significantly reduced malaria in the respective cohorts order (p<0.05). Similarly malaria prevalence in NICs was 6times higher than in CICs (4.62%) and significantly reduced malaria PD+HE (2.44%) > ITN+ES (2.66%) > IRS+ITN (3.89%) when compared to SICs (p<0.05). Man biting rates (MBR) of the malarial transmitting vectors (Anopheles gambiae and An. funestus) were 59.64% and 40.35% and their proportions were significantly higher in dry season than in wet season for both urban and rural areas (p<0.05). NICs had greater proportions of malaria vectors (300) with insignificantly Infectedremales compared to ICs (p<0.05). NICs and SICs showed that significantly greater parous mosquitoes were caught before intervention. However, sporozoite rate (SPR) of mosquitoes from ICs were comparable to those from NICs (p>0.05). Also entomological inoculation rate (EIR) of Anopheles mosquitoes from NICs (ITN 0.1999, PD 0.0998, IRS 0.1995) compared to EIR from SICs/households (ITN 0.0995, PD 0.0000, IRS 0.0998) were insignificantly higher (p<0.05). NICs and CICs showed that significantly higher parous mosquitoes were caught from NICs/households (p<0.05). SPR from NICs (ITN+ES 1.25%, PD+HE 2.32%, IRS+ITN 2.66%) were higher compared to SPR from CICs (ITN+ES 0.00%, PD+HE 0.00%, IRS+ITN 2.12%). Similarly EIR from NICs (ITN+ES 0.0997%, PD+HE 0.0997%, IRS+ITN 0.1995%) when compared to EIR from CICs (ITN+ES 0.000%, PD+HE 0.000%, IRS+ITN 0.0996%) were insignificantly higher (p>0.05). Current evidence strongly support combined intervention for protective effect in malaria protection. Even though PD+HE was found to be most encouraging, the role of others are equally important as adjunts in the global drive to eliminate malaria.