Abstract:
Background: Kenya employed combination of long lasting insecticidal nets (LLINs)
and non-pyrethroid indoor residual spray (IRS) in 2017 and 2018 as a strategy to
address the widespread pyrethroid resistance which is threatening to affect the
progress towards malaria elimination.
Objectives: To evaluate the effectiveness of combined use of non-pyrethroid IRS and
LLINs on malaria indicators and assess awareness and acceptability of the two
interventions among the residents of Nyatike and Suba sub-Counties in Western
Kenya.
Methods: Record review and tally of monthly aggregates of outpatient attendance,
suspected malaria cases and number tested for malaria and number positive for
malaria at Karungu
Sub-county Hospital in Nyatike (intervention area) and Suba Sub-county Hospital in
Suba (comparison area) was done for pre-intervention (1 February 2016 to 31 January
2017) and post-intervention periods (1 April 2017 to 31 March 2018). Interviews and
screening for malaria was done among febrile clients at outpatient departments of the
two health facilities. Data analyses were done using Epi Info 7 and Stata. Poisson
regression was used to determine the effectiveness of the intervention in the presence
of confounders. Descriptive statistics was used to evaluate awareness and level of
acceptability for LLINs and IRS by the residents.
Results: Annual malaria incidences among all ages reduced by 89% from 360 per
1000 in pre-intervention to 38 per 1000 in post-intervention in intervention area and
reduced by 52% from 131 per 1000 to 78 per 1000 in the comparison area. Among
the under 5 children, the net change in annual malaria incidence was 308 per 1000
population (RR=0.25, 95CI 0.24-0.29 p<0.001).Test positivity rate among the febrile
clients was 8% (15/187) and 12% (22/187) in Nyatike and Suba sub-Counties
respectively. The majority of the clients had heard about free mass net distribution
and IRS campaigns. The level of acceptability for LLINs was 94% in Nyatike and
93% in Suba while the level of acceptability for IRS was 61% in Nyatike and 65% in
Suba.
Conclusion: Combination of non-pyrethroid IRS and LLINs provided greater
protection against malaria. The TPR was lower in Nyatike than in Suba sub-County.
The level of awareness was high for both LLINs and IRS. The level of acceptability
was high for LLINs but considerably lower for IRS in both sub-counties.
Recommendations: Scale up of combined use of LLINs and non-pyrethroid IRS in
all malaria endemic areas and address factors contributing to low acceptability for IRS
through adequate community sensitization and health education
