Volatile pyrethroid spatial repellents for preventing mosquito bites: a systematic review and meta-analysis

Area of Science:

• Medical Entomology
• Public Health
• Vector Control

Background:

• Volatile pyrethroid spatial repellents (VPSRs) are crucial for preventing mosquito-borne diseases like malaria and dengue.
• Varied evaluation methods have created uncertainty regarding the protective efficacy (PE) of VPSRs.
• This review consolidates entomological evidence on VPSR PE against various mosquito species and testing methodologies.

Purpose of the Study:

• To systematically review and meta-analyze the entomological evidence base for VPSR protective efficacy.
• To assess PE against Anopheles, Aedes, and Culex mosquitoes.
• To compare the effectiveness of different testing methods and settings.

Main Methods:

• Systematic review and meta-analysis of studies from January 2000 to September 2023.
• Included semi-field and field studies measuring PE via human landing catch (HLC) or mosquito trap density.
• Pooled mosquito-level and weather data; analyzed PE by product, active ingredient, capture method, species, and setting.

Main Results:

• VPSRs demonstrated an average PE of 56% against mosquito bites.
• Human landing catch (HLC) provided the highest PE estimates (58% in semi-field, 50% in field studies).
• Lower PE observed for Anopheles funestus (31%); efficacy was consistent across indoor and outdoor settings and unaffected by weather.

Conclusions:

• VPSRs offer significant protection against mosquito contact, with semi-field and field data aligning.
• Human landing catch (HLC) is the preferred method for evaluating VPSR efficacy.
• Further field studies on outdoor protection are essential in malaria-endemic areas of Africa, South America, and Southeast Asia.