ZeroFly® Shelter - Evidence of the Impact of Insecticide-Treated Plastic Sheeting/Tarpaulins and Tents

Insecticide-treated plastic tarpaulins for control of malaria vectors in refugee camps

Reference

Graham K. et al. 2002. Medical and Veterinary Entomology

Objective

To compare the insecticidal efficacy of plastic tarpaulin sprayed with deltamethrin on its 2 inner surface (target dose 30mg/m²), tarpaulin impregnated with deltamethrin (initially > 2 30mg/m²) during manufacture, and a tent made from the factory impregnated tarpaulin material.

Key Findings

Laboratory and field experiments confirm a level of efficacy near 100% for ZeroFly® plastic sheeting. In refugee camps where coverage is high, the prospect for malaria control would remain high due to the mass killing effect of vector mosquitoes.

Conclusion

Insecticide-treated plastic sheeting has potential as a wider public health tool against various vector-borne diseases in refugee camps.

The indoor use of plastic sheeting pre-impregnated with insecticide for control of malaria vectors

Reference

Diabate A. et al. 2006. Tropical Medicine and International Health

Objective

To evaluate the efficacy of pyrethroid-treated plastic sheeting (ITPS) applied as a lining to the ceiling or walls of rooms against pyrethroid-susceptible and pyrethroid-resistant Anopheles gambiae.

Key Findings

ITPS had a major effect on the mortality of mosquitoes, the proportion killed being dependent upon the surface area covered. Homozygotes for kdr resistance showed lower
rates of mortality than did heterozygotes or homozygotes for susceptibility. Deterred entry of mosquitoes and inhibition of blood feeding were also correlated with surface area
covered. The mode of action and efficacy of ITPS seems to bear closer resemblance to that induced by indoor residual spraying (IRS) than to that induced by insecticide-treated nets.

Conclusion

ITPS might be conceived as being equivalent to long-lasting or permanent IRS but without some of the operational constraints normally associated with spraying. High coverage of ITPS could potentially have a mass population effect on mosquitoes and give rise to long-term community protection against malaria.

Tents pre-treated with insecticide for malaria control in refugee camps: an entomological evaluation

Reference

Graham K. et al. 2004. Malaria Journal

Objective

To evaluate the entomological efficacy of tents made of untreated canvas with deltamethrin-treated polyethylene threads interwoven through the canvas during manufacture (from which ZeroFly® is constructed).

Key Findings

The insecticide-treated tents were effective both in killing mosquitoes and reducing blood-feeding. Mean 24 hour mortality was 25.7% on untreated tents and 50.8% on treated tents in wild anophelines and 5.2% on untreated tents and 80.9% on treated tents in insectary-reared Anopheles stephensi. Blood-feeding of wild anophelines was reduced from 46% in the presence of an untreated tent to 9.2% in the presence of treated tents and from 51.1% to 22.2% for insectary-reared An. stephensi. In contact bioassays on tents weathered for three months there was 91.3% mortality after 10-minute exposure and a 24 h holding period and 83.0% mortality after 3-minute exposure and a 24 h holding period.

Conclusion

The use of pyrethroid-treated tents is already established as a malaria control intervention. A technology that enables tents to be pre-treated with insecticide during manufacture and be shown to retain insecticidal efficacy for up to one year would improve the feasibility of malaria control during the acute stage of an emergency.