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. 2017 Feb 17;16(1):82.
doi: 10.1186/s12936-017-1710-6.

Experimental hut evaluation of a novel long-lasting non-pyrethroid durable wall lining for control of pyrethroid-resistant Anopheles gambiae and Anopheles funestus in Tanzania

Robert Malima  1   2 , Basiliana Emidi  3 , Louisa A Messenger  4 , Richard M Oxborough  4 , Bernard Batengana  5 , Wema Sudi  5 , Sophie Weston  4 , George Mtove  5 , Joseph P Mugasa  5 , Franklin W Mosha  3 , Mark W Rowland  4 , William Kisinza  5
Affiliations

Experimental hut evaluation of a novel long-lasting non-pyrethroid durable wall lining for control of pyrethroid-resistant Anopheles gambiae and Anopheles funestus in Tanzania

Robert Malima et al. Malar J. .

Abstract

Background: A novel, insecticide-treated, durable wall lining (ITWL), which mimics indoor residual spraying (IRS), has been developed to provide prolonged vector control when fixed to the inner walls of houses. PermaNet® ITWL is a polypropylene material containing non-pyrethroids (abamectin and fenpyroximate) which migrate gradually to the surface.

Methods: An experimental hut trial was conducted in an area of pyrethroid-resistant Anopheles gambiae s.l. and Anopheles funestus s.s. to compare the efficacy of non-pyrethroid ITWL, long-lasting insecticidal nets (LLIN) (Interceptor®), pyrethroid ITWL (ZeroVector®), and non-pyrethroid ITWL + LLIN.

Results: The non-pyrethroid ITWL produced relatively low levels of mortality, between 40-50% for An. funestus and An. gambiae, across all treatments. Against An. funestus, the non-pyrethroid ITWL when used without LLIN produced 47% mortality but this level of mortality was not significantly different to that of the LLIN alone (29%, P = 0.306) or ITWL + LLIN (35%, P = 0.385). Mortality levels for An. gambiae were similar to An. funestus with non-pyrethroid ITWL, producing 43% mortality compared with 26% for the LLIN. Exiting rates from ITWL huts were similar to the control and highest when the LLIN was present. An attempt to restrict mosquito access by covering the eave gap with ITWL (one eave open vs four open) had no effect on numbers entering. The LLIN provided personal protection when added to the ITWL with only 30% blood-fed compared with 69 and 56% (P = 0.001) for ITWL alone. Cone bioassays on ITWL with 30 min exposure after the trial produced mortality of >90% using field An. gambiae.

Conclusions: Despite high mortality in bioassays, the hut trial produced only limited mortality which was attributed to pyrethroid resistance against the pyrethroid ITWL and low efficacy in the non-pyrethroid ITWL. Hut ceilings were left uncovered and may have served as a potential untreated refuge. By analogy to IRS campaigns, which also do not routinely treat ceilings, high community coverage with ITWL may still reduce malaria transmission. Restriction of eave gaps by 75% proved an inadequate barrier to mosquito entry. The findings represent the first 2 months after installation and do not necessarily predict long-term efficacy.

Keywords: Experimental huts; Insecticide-treated wall lining; Long-lasting insecticidal nets; Malaria control; Pyrethroid resistance.

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Figures

Fig. 1
Fig. 1
a East African experimental huts in Zeneti village, Muheza District, northeast Tanzania. b Pyrethroid ITWL (ZeroVector®). c Non-pyrethroid ITWL (PermaNet® Lining) + LLIN (Interceptor®) with eaves partially blocked. d Eave baffles and hessian sack cloth ceiling
Fig. 2
Fig. 2
Percentage mortality of pyrethroid-resistant Anopheles funestus s.s. in the experimental hut trial. Percentage mortality was recorded 24 and 72 h after morning collections from huts. If the superscript for a time period (24 or 72 h) is the same, there was no significant difference between treatments (P > 0.05)
Fig. 3
Fig. 3
Percentage mortality of pyrethroid-resistant Anopheles gambiae s.l. in the experimental hut trial. Percentage mortality was recorded 24 and 72 h after morning collections from huts. If the superscript for a time period (24 or 72 h) is the same, there was no significant difference between treatments (P > 0.05)
Fig. 4
Fig. 4
Percentage mortality of pyrethroid-susceptible Anopheles gambiae Kisumu, pyrethroid-resistant Anopheles gambiae Muleba-Kis and F1 offspring of field-collected Anopheles gambiae s.l. in WHO cone and cylinder bioassays on non-pyrethroid ITWL
Fig. 5
Fig. 5
Cumulative percentage of pyrethroid-susceptible Anopheles gambiae Kisumu, and F1 offspring of field-collected Anopheles gambaie s.l. taking off over time, following exposure to untreated netting, Interceptor® LLIN or non-pyrethroid ITWL
Fig. 6
Fig. 6
Percentage mortality of F1 offspring of field-collected Anopheles gambiae s.l. in WHO cylinder bioassays, following different exposures times to non-pyrethroid ITWL
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References

    1. WHO. Global Malaria Programme. World Malaria Report 2014. Geneva: World Health Organization; 2014. http://www.who.int/malaria/publications/world_malaria_report_2014/en/. Accessed 12 Jan 2017.
    1. Ranson H, N’Guessan R, Lines J, Moiroux N, Nkuni Z, Corbel V. Pyrethroid resistance in African anopheline mosquitoes: what are the implications for malaria control? Trends Parasitol. 2011;27:91–98. doi: 10.1016/j.pt.2010.08.004. - DOI - PubMed
    1. Corbel V, Akogbeto M, Damien GB, Djenontin A, Chandre F, Rogier C, et al. Combination of malaria vector control interventions in pyrethroid resistance area in Benin: a cluster randomised controlled trial. Lancet Infect Dis. 2012;12:617–626. doi: 10.1016/S1473-3099(12)70081-6. - DOI - PubMed
    1. Singh M, Brown G, Rogerson SJ. Ownership and use of insecticide-treated nets during pregnancy in sub-Saharan Africa: a review. Malar J. 2013;12:268. doi: 10.1186/1475-2875-12-268. - DOI - PMC - PubMed
    1. Irish S, N’Guessan R, Boko P, Metonnou C, Odjo A, Akogbeto M, et al. Loss of protection with insecticide-treated nets against pyrethroid-resistant Culex quinquefasciatus mosquitoes once nets become holed: an experimental hut study. Parasit Vectors. 2008;1:17. doi: 10.1186/1756-3305-1-17. - DOI - PMC - PubMed

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