Table 1.
Summary of experimental hut trials demonstrating the impact of insecticide-treated housing materials on malaria vector control
| Field site, country, trial type | Intervention(s) | Insecticide (dosage) | Intervention coverage | Control(s) (dosage) | Major malaria vector speciesresistance status | Entomological parametersb | References | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mortality | Deterrence | Exiting rates | Blood feeding inhibition | Personal protection | Impact on insecticide resistance | |||||||
| Afghan refugee camp, Pakistan, experimental platforms | Impregnated polythene tarpaulins | Deltamethrin | Full coveragea | Untreated polythene tarpaulin | An. subpictus ND, An. stephensi ND | High mosquito mortality (86–100%); no significant differences between interventions | ND | ND | No impact on blood feeding (~20% for all interventions) | ND | ND | [36] |
| (45 mg/m2) | ||||||||||||
| Sprayed polythene tarpaulins | (30 mg/m2) | |||||||||||
| Impregnated polythene tents | (45 mg/m2) | |||||||||||
| Afghan refugee camp, Pakistan, experimental platforms | Polyethylene canvas | Deltamethrin (ND) | Full coverage | Untreated canvas tent | Anophelines (spp. grouped)ND | Increased mosquito mortality relative to control (51 vs. 26%, respectively) | No significant reduction in mean no. of mosquitoes relative to control (7 vs. 19, respectively) | ND | Reduced blood feeding relative to control (9 vs. 46%, respectively) | ND | ND | [37] |
| Bobo Dioulasso, Burkina Faso, experimental West African huts [50] | Polyethylene sheeting | Permethrin (2% w/w) | Ceiling only | Untreated polyethylene sheeting | An. gambiae r | Mortality correlated with coverage (20% for two walls; 45% for four walls; 46% for four walls + ceiling covered) | Deterrence correlated with coverage (28% for two walls; 43% for four walls; 46% for four walls + ceiling covered) | All treatments highly repellent (induced-exophily 68–78%) | No significant impact on blood feeding; level of inhibition correlated with surface area covered (10% for two walls vs. 27% for four walls + ceiling) | ND | Mortality and blood feeding inhibition kdr r/kdr r < kdr r/kdr s + kdr s/kdr s (19 vs. 64% and 12 vs. 62% for four walls + ceiling, respectively) | [38] |
| Two walls | ||||||||||||
| Four walls | Untreated control | |||||||||||
| Four walls + ceiling | ||||||||||||
| Cotonou, Benin, experimental West African huts | Polypropylene mesh | Bendiocarb (200 mg/m2) | Top thirds of walls | Deltamethrin-treated mosquito net (ITN; 45 mg/m2) | An. gambiae r | Mortality proportional to wall surface area covered (80% vs. 100% for upper third of wall or full coverage, respectively) | No significant reduction in mean no. of mosquitoes in full coverage hut relative to control (202 vs. 206, respectively) | ND | High levels of blood feeing inhibition; no significant increase when combining wall treatments with ITNs compared to ITNs alone (100% vs. 94%, respectively) | ND | ND | [39] |
| Full coverage | Untreated mosquito net | |||||||||||
| Bobo Dioulasso, Burkina Faso, experimental West African huts | Polypropylene sheeting (ITPS) | Bendiocarb (400 mg/m2) | Upper thirds of walls | Deltamethrin LLIN (PermaNet® 2.0; 55 mg/m2) | An. gambiae r | Significantly higher mosquito mortality when interventions used in combination (ITPS + LLIN: 73% vs. ITPS alone: 53%) | ND | Significantly higher vector exophily when interventions combined (LLIN + IRS: 61%; ITPS + LLINs: 50%) | Significant blood feeding inhibition only when ITPS combined with LLIN (58%) relative to untreated control | ND | Frequency of ace-1 R allele significantly higher among heterozygote survivors from individual IRS and ITPS treatments but not when combined with LLIN | [41] |
| IRS (bendiocarb; 400 mg/m2) | Mortality similar for partial coverage of ITPS vs. full coverage with IRS (53% vs. 42%, respectively) | |||||||||||
| Untreated mosquito net | ||||||||||||
| Bobo Dioulasso, Burkina Faso, experimental West African huts | Polyethylene sheeting (ITPS) | Permethrin (2% w/w) | Full coverage | Holed permethrin LLIN (Olyset®; 2% w/w) | An. gambiae r | Significantly higher mosquito mortality when ITPS used in combination with LLIN (60%) compared to alone (34%) | No significant reductions in mean no. of mosquitoes in ITPS huts without (443) or with untreated nets (309-315), relative to control (422) | Significant increase in exophily for single (ITPS alone: 80%; LLIN alone: 77%) and combined interventions (ITPS + LLIN: 79%) | Combined use of ITPS + LLIN did not significantly increase blood feeding inhibition over LLIN alone (75% vs. 82%, respectively) | Combined use of ITPS + LLIN significantly increased personal protection over LLIN alone (88% vs. 16%, respectively | Significantly more kdr r/kdr r dead with LLIN (55%) and ITPS + LLIN (67%) than ITPS alone (17%) | [42] |
| Intact or holed untreated mosquito net | ||||||||||||
| Untreated control | ||||||||||||
| Muheza, Tanzania, experimental East African huts [51] | Polyester wall hangings (NWH) | Pirimiphos methyl (1 g/m2) | Ceiling only | Untreated control | An. gambiae s.l.s/r(c) , An. funestus | An. gambiae and An. funestus mortality significantly higher for p-methyl NWH than deltamethrin NWHs (92% vs. 11% and 78% vs. 6%, respectively for two walls) | Significant reductions in mosquito entry for p-methyl (65–95%) and deltamethrin (50–56%) treated NWH | Significantly increased exiting rates in NWH huts compared to untreated control | Limited effect on blood feeding rates (52–77%) relative to untreated control (64–67%) | ND | ND | [46] |
| Two walls | ||||||||||||
| Four walls | An. gambiae and An. funestus mortality significantly higher for two walls than ceilings only (59 and 39%, respectively) | Deterrence increased with increasing coverage (65–77% vs. 92–95% for two walls vs. four walls + ceiling) | ||||||||||
| Four walls + ceiling | ||||||||||||
| No improvement in mosquito mortality when coverage increased beyond two walls | ||||||||||||
| Deltamethrin (55 mg/m2) | Two walls | |||||||||||
| Tiassalé, Côte d’Ivoire, experimental West African huts | Polyethylene wall lining (WL) | Pirimiphos methyl (1 g/m2) | Four walls | Holed deltamethrin LLIN (PermaNet® 2.0; 55 mg/m2) | An. gambiae s.s.r | Significantly higher mortality with p-methyl WL than pyrethroid WL (66% vs. 32%, respectively) | Significant reductions in mosquito entry for p-methyl WL/NHW only when combined with LLIN (59%/65% vs. 28%/3%, respectively) | Significantly increased exiting rates for p-methyl WL (53%) and p-methyl NWH + LLIN (59%), relative to untreated control (29%) | Limited effect on blood feeding rates (82–94%) relative to untreated control (95%), unless combined with LLIN (9–13%) | Limited personal protection for p-methyl WL/NWH relative to untreated control (4%/0%), unless combined with LLIN (93%/92%) | Significantly higher numbers of ace-1 R heterozygote (RS) and homozygote (RR) survivors compared to susceptible homozygotes (SS) following exposure to p-methyl WLs/NHWs | [47] |
| Four walls + ceiling | ||||||||||||
| Holed untreated mosquito net | No improvement in mosquito mortality when p-methyl WL/NWH coverage increased from walls only (66%/49%) to walls + ceilings (56%/69%) | Combined WL and LLIN did not limit the selection of ace-1 R compared to WL alone | ||||||||||
| Nylon NHW | Pirimiphos methyl (1 g/m2) | Four walls | ||||||||||
| Four walls + ceiling | Untreated plastic sheeting | No increase in mosquito mortality when WL/NHW combined with LLINs (72%/61% vs. 61%/53%, respectively) | ||||||||||
| Polyethylene WL (ZeroVector®) | Deltamethrin (175 mg/m2) | Four walls | ||||||||||
| Bobo Dioulasso, Burkina Faso, experimental West African huts | Polyethylene WL | Pirimiphos methyl (1 g/m2) | Four walls | Holed deltamethrin LLIN (PermaNet® 2.0; 55 mg/m2) | An. gambiae s.s.s/r(c) | Significantly higher mortality with p-methyl WL than pyrethroid WL (>95% vs. 40%, respectively) | Largest reductions in mosquito entry for pyrethroid WL and p-methyl WL when used in combination with LLIN (74 and 62%, respectively) | Significantly increased exiting rates for p-methyl WL (53%), relative to untreated control (33%) | Blood feeding significantly reduced when p-methyl WL/NWHs combined with LLIN (91%/90% vs. 50/50%, respectively) | Personal protection for p-methyl WL/NWH relative to untreated control (56%/72%), increased when combined with LLIN (95%/94%) | Significantly higher numbers of ace-1 R survivors (100%) following exposure to p-methyl WL alone, compared to susceptible vectors (32%) | [48] |
| Four walls + ceiling | ||||||||||||
| Holed untreated mosquito net | Significantly higher mortality with p-methyl WL/NHW either alone or in combination with LLIN (100% for all) | Combined WL and LLIN limited the selection of ace-1 R compared to WL alone | ||||||||||
| Nylon NHW | Pirimiphos methyl (1 g/m2) | Four walls | ||||||||||
| Four walls + ceiling | Untreated plastic sheeting | No significant increase in mortality when pyrethroid WL combined with LLINs (48% vs. 40%, respectively) | ||||||||||
| Polyethylene WL (ZeroVector®) | Deltamethrin (175 mg/m2) | Four walls | ||||||||||
| Four walls + ceiling | ||||||||||||
IRS indoor residual spraying, ITN insecticide-treated net, ITPS insecticide-treated plastic sheeting, LLIN long-lasting insecticidal net, ND not described, NWH net wall hangings, r resistant to one or more insecticides under investigation, s susceptible to one or more insecticides under investigation, WL wall lining
aFull coverage defined as four inner walls in experimental huts or all interior surfaces in a λ-shaped tent, as applicable
bEntomological parameters reported relative to untreated control, unless otherwise specified
cResistant to pyrethroids but susceptible to organophosphates