Abstract:

A comprehensive, village-scale long-term malaria vector control was implemented around Balombo town (Benguela Province, Angola), to compare the efficacy of four methods.

Methods

Four methods were implemented, each one in two villages: long-lasting insecticide treated nets LLINs PermaNet® P2.0 alone; insecticide-treated plastic sheeting (ITPS) model ZeroVector® (ZV) alone; combination LLIN P2.0 and ITPS model ZeroFly® (ZF) and ITPS after two rounds of inside residual spraying (IRS)
Two cross-sectional parasitological surveys were done before vector control (February 2008) and ten years after (February 2018) in asymptomatic children ≤15-year-old, in the eight villages.
Two parasitological indicators were analyzed: Plasmodium prevalence and parasitaemia.

Results

1,648 thick blood films (TBF) were prepared. Plasmodium (largely P. falciparum) was observed in 637 TBF, (overall parasite prevalence=38.6%). A significant decrease, by 32%; occurred between before (44.2%; n=1,004) and after vector (29.9%; n= 644).
The parasite prevalence remained similar in villages furnished in LLIN and decreased with the three other methods.
The evolution of parasite load was opposite, with a significant increase between 2008 and 2018 in the whole sample but not in children ≤5-year-old (at risk group) covered with LLIN.
No parasitological rebound was observed.

Conclusion

The diversity of information according to age-group, vector control method and parasitological indicator, highlight the need for long-term, comprehensive, evaluation in several villages before drawing any definitive conclusion.
The combination LLIN nets and ITPS was not better than ITPS only, which was as efficient as indoor residual spraying, and may constitute an interesting new tool for the national malaria control programme.