Abstract:
BACKGROUND : South Africa uses indoor residual spraying (IRS) for vector control in its malaria control programme
(MCP). Insecticide-treated wall linings (ITWLs) offer possible advantages over IRS and long-lasting, insecticide-treated
nets (LLINs). This study assessed the user acceptability and perceived effectiveness, and the durability, including efficacy
through bioassays, of a newly developed, monofilament polyethylene ITWL.
METHODS : Four ITWL formulations/treatments, two incorporated with deltamethrin and two with alpha-cypermethrin
in concentrations ranging from 0.29 to 0.85 wt%, and untreated linings were randomly installed on the inner
walls of traditional mud huts (n = 20) and modern brick houses (n = 20) in a community village in Vhembe District,
Limpopo Province. The linings were exposed to conditions within these dwellings over 6 months. Data were collected
monthly through questionnaires and entomological residual efficacy analysis of ITWL, as part of durability testing, was
done bimonthly using WHO prescribed bioassays.
RESULTS : Monofilament polyethylene ITWLs were successfully installed in traditional sleeping huts and in bedrooms
of modern type brick houses. ITWL remained intact throughout the entire 6 months of the study. Participants did
not express any dissatisfaction towards the linings although two participants indicated the product should be fitted
at a lower level for better results. User perceived effectiveness was very high with participants reporting observed
mortality of mosquitoes and other nuisance insects. This perception coincided with results obtained through residual
efficacy bioassays where a 100 % knockdown and mortality of mosquitoes was recorded throughout the trial period.
Acceptability regarding appearance, including colour, position and attachment method, was also satisfactory with
some participants citing the lining as decorative. All participants opted to keep ITWL and residual long-term efficacy
will be determined annually for a further 3 years.
CONCLUSIONS : The newly developed ITWLs are highly accepted amongst participants in an unsprayed section of a village
in a malaria-endemic area. The perceived effectiveness that coincides with results obtained through bioassays and acceptance
of the overall appearance of ITWL will be evaluated over a longer term to determine sustainability. With further developing
and testing, this ITWL has the potential to become a sustainable and safer alternative vector control method.
