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Modified mosquito landing boxes dispensing transfluthrin provide effective protection against Anopheles arabiensis mosquitoes under simulated outdoor conditions in a semi-field system.

Andrés M, Lorenz LM, Mbeleya E, Moore SJ - Malar. J. (2015)

Bottom Line: Two MLBs were located 5 m from a human volunteer to investigate the repellent effects of a transfluthrin 'bubble' created between the MLBs.A fully randomized cross-over design was performed in a large, semi-field, screened cage to assess the effect of the repellent against laboratory-reared Anopheles arabiensis mosquitoes under ambient outdoor conditions.Transfluthrin-treated strips continued to knock down mosquitoes in laboratory tests, 3 weeks after impregnation, although this effect diminished with time.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular Neurobiology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany. martaandresm@gmail.com.

ABSTRACT

Background: Efforts to control malaria vectors have primarily focused on scaling-up of long-lasting insecticidal nets (LLINs) and indoor residual spraying. Although highly efficient against indoor-biting and indoor-resting vectors, these interventions have lower impact on outdoor-biting mosquitoes. Innovative vector control tools are required to prevent outdoor human-mosquito contacts. In this work, the potential of spatial repellents, delivered in an active system that requires minimal user compliance, to provide personal protection against exophagic mosquitoes active in the early evening was explored.

Methods: A device previously used as an odour-baited lure and kill apparatus, the mosquito landing box (MLB), was modified to dispense the volatile synthetic pyrethroid, transfluthrin, as a spatial repellent. The MLB has an active odour-dispensing mechanism that uses a solar-powered fan and switches on at dusk to provide long duration dispensing of volatile compounds without the need for the user to remember to employ it. Two MLBs were located 5 m from a human volunteer to investigate the repellent effects of a transfluthrin 'bubble' created between the MLBs. Transfluthrin was emanated from polyester strips, hanging inside the MLB odour-dispensing unit. A fully randomized cross-over design was performed in a large, semi-field, screened cage to assess the effect of the repellent against laboratory-reared Anopheles arabiensis mosquitoes under ambient outdoor conditions. The knock-down capacity of the transfluthrin-treated strips was also evaluated at different time points up to 3 weeks after being impregnated to measure duration of efficacy.

Results: The protective transfluthrin bubble provided 68.9% protection against An. arabiensis bites under these simulated outdoor conditions. Volatile transfluthrin caused low mortality among mosquitoes in the semi-field system. Transfluthrin-treated strips continued to knock down mosquitoes in laboratory tests, 3 weeks after impregnation, although this effect diminished with time.

Conclusion: Modified MLBs can be used as efficient and long-lasting dispensers of volatile spatial repellents such as transfluthrin, thereby providing high levels of protection against outdoor-biting mosquitoes in the peri-domestic space. They have a potential role in combatting outdoor malaria transmission without interfering with effective indoor interventions such as LLINs.

No MeSH data available.


Related in: MedlinePlus

Modified mosquito landing box. a The lateral panels from the mosquito landing box (MLB) previously described in Matowo et al. [13] were removed to allow a better dispersion of the repellent. A solar battery (arrowhead) provides the energy to power the fan that draws the air emanated by the strips. b A deflecting dish (asterisk) is attached to the underside top cover to disperse the air driven by the fan. c The dispensing unit consists of a PVC pipe (arrowhead) with a fan on the top of it. The polyester strips are hanging from a cable wire within the dispensing tube (arrow).
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Fig1: Modified mosquito landing box. a The lateral panels from the mosquito landing box (MLB) previously described in Matowo et al. [13] were removed to allow a better dispersion of the repellent. A solar battery (arrowhead) provides the energy to power the fan that draws the air emanated by the strips. b A deflecting dish (asterisk) is attached to the underside top cover to disperse the air driven by the fan. c The dispensing unit consists of a PVC pipe (arrowhead) with a fan on the top of it. The polyester strips are hanging from a cable wire within the dispensing tube (arrow).

Mentions: The structure of the MLB has previously been described [13]. In its original design, the MLB consisted of a wooden box measuring 0.7 × 0.7 × 0.8 m on short wooden pedestals that raised it 10 cm above ground. For this study, the side panels were removed, leaving only the wooden box structure to allow for a better dispersion of the repellent volatiles (Figure 1a). The dispensing unit consists of a short PVC pipe of 5.7 cm diameter and 20 cm length held by suspension wires to the wooden frame. A 12 V fan to the top of the PVC pipe that draws air upwards through the dispensing unit (Figure 1c). The fan is powered by a 12 V, 7.2 A battery charged by a 20 W solar panel that switches on at dusk using a photoswitch. The polyester strips with repellent are hung within the PVC pipe. A deflecting dish is attached to the underside top cover of the MLB to redirect the air drawn upward by the fan in all directions (Figure 1b).Figure 1


Modified mosquito landing boxes dispensing transfluthrin provide effective protection against Anopheles arabiensis mosquitoes under simulated outdoor conditions in a semi-field system.

Andrés M, Lorenz LM, Mbeleya E, Moore SJ - Malar. J. (2015)

Modified mosquito landing box. a The lateral panels from the mosquito landing box (MLB) previously described in Matowo et al. [13] were removed to allow a better dispersion of the repellent. A solar battery (arrowhead) provides the energy to power the fan that draws the air emanated by the strips. b A deflecting dish (asterisk) is attached to the underside top cover to disperse the air driven by the fan. c The dispensing unit consists of a PVC pipe (arrowhead) with a fan on the top of it. The polyester strips are hanging from a cable wire within the dispensing tube (arrow).
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4477292&req=5

Fig1: Modified mosquito landing box. a The lateral panels from the mosquito landing box (MLB) previously described in Matowo et al. [13] were removed to allow a better dispersion of the repellent. A solar battery (arrowhead) provides the energy to power the fan that draws the air emanated by the strips. b A deflecting dish (asterisk) is attached to the underside top cover to disperse the air driven by the fan. c The dispensing unit consists of a PVC pipe (arrowhead) with a fan on the top of it. The polyester strips are hanging from a cable wire within the dispensing tube (arrow).
Mentions: The structure of the MLB has previously been described [13]. In its original design, the MLB consisted of a wooden box measuring 0.7 × 0.7 × 0.8 m on short wooden pedestals that raised it 10 cm above ground. For this study, the side panels were removed, leaving only the wooden box structure to allow for a better dispersion of the repellent volatiles (Figure 1a). The dispensing unit consists of a short PVC pipe of 5.7 cm diameter and 20 cm length held by suspension wires to the wooden frame. A 12 V fan to the top of the PVC pipe that draws air upwards through the dispensing unit (Figure 1c). The fan is powered by a 12 V, 7.2 A battery charged by a 20 W solar panel that switches on at dusk using a photoswitch. The polyester strips with repellent are hung within the PVC pipe. A deflecting dish is attached to the underside top cover of the MLB to redirect the air drawn upward by the fan in all directions (Figure 1b).Figure 1

Bottom Line: Two MLBs were located 5 m from a human volunteer to investigate the repellent effects of a transfluthrin 'bubble' created between the MLBs.A fully randomized cross-over design was performed in a large, semi-field, screened cage to assess the effect of the repellent against laboratory-reared Anopheles arabiensis mosquitoes under ambient outdoor conditions.Transfluthrin-treated strips continued to knock down mosquitoes in laboratory tests, 3 weeks after impregnation, although this effect diminished with time.

View Article: PubMed Central - PubMed

Affiliation: Department of Cellular Neurobiology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany. martaandresm@gmail.com.

ABSTRACT

Background: Efforts to control malaria vectors have primarily focused on scaling-up of long-lasting insecticidal nets (LLINs) and indoor residual spraying. Although highly efficient against indoor-biting and indoor-resting vectors, these interventions have lower impact on outdoor-biting mosquitoes. Innovative vector control tools are required to prevent outdoor human-mosquito contacts. In this work, the potential of spatial repellents, delivered in an active system that requires minimal user compliance, to provide personal protection against exophagic mosquitoes active in the early evening was explored.

Methods: A device previously used as an odour-baited lure and kill apparatus, the mosquito landing box (MLB), was modified to dispense the volatile synthetic pyrethroid, transfluthrin, as a spatial repellent. The MLB has an active odour-dispensing mechanism that uses a solar-powered fan and switches on at dusk to provide long duration dispensing of volatile compounds without the need for the user to remember to employ it. Two MLBs were located 5 m from a human volunteer to investigate the repellent effects of a transfluthrin 'bubble' created between the MLBs. Transfluthrin was emanated from polyester strips, hanging inside the MLB odour-dispensing unit. A fully randomized cross-over design was performed in a large, semi-field, screened cage to assess the effect of the repellent against laboratory-reared Anopheles arabiensis mosquitoes under ambient outdoor conditions. The knock-down capacity of the transfluthrin-treated strips was also evaluated at different time points up to 3 weeks after being impregnated to measure duration of efficacy.

Results: The protective transfluthrin bubble provided 68.9% protection against An. arabiensis bites under these simulated outdoor conditions. Volatile transfluthrin caused low mortality among mosquitoes in the semi-field system. Transfluthrin-treated strips continued to knock down mosquitoes in laboratory tests, 3 weeks after impregnation, although this effect diminished with time.

Conclusion: Modified MLBs can be used as efficient and long-lasting dispensers of volatile spatial repellents such as transfluthrin, thereby providing high levels of protection against outdoor-biting mosquitoes in the peri-domestic space. They have a potential role in combatting outdoor malaria transmission without interfering with effective indoor interventions such as LLINs.

No MeSH data available.


Related in: MedlinePlus