Methods for detecting insecticide resistance in sand flies: A systematic review

Area of Science:

• Medical Entomology
• Vector Control
• Insecticide Resistance

Background:

• Current insecticide resistance classification in sand flies often uses methodologies developed for mosquitoes, which can lead to inaccurate interpretations due to biological differences.
• Standardized protocols for assessing sand fly susceptibility to insecticides are lacking, leading to varied and unreliable results.

Purpose of the Study:

• To review and analyze existing literature on sand fly insecticide susceptibility testing.
• To identify methodological parameters used in sand fly resistance studies.
• To propose improvements for more accurate insecticide resistance estimation in sand flies.

Main Methods:

• A systematic literature search was conducted in four databases (PubMed, Scopus, BVS, ScienceDirect) for studies published until December 2019.
• Keywords related to sand fly insecticide susceptibility and resistance were used for the search.
• A total of 3481 articles were identified, and 61 were selected for analysis.

Main Results:

• 47 sand fly populations showed confirmed insecticide resistance across species like Phlebotomus papatasi, Ph. argentipes, and Sergentomyia shorttii.
• 28 populations exhibited resistance in species including Ph. papatasi, Ph. argentipes, Ph. sergenti, and Lutzomyia longipalpis.
• Only three studies compared field and colony populations, with all colony populations showing reduced susceptibility to at least one insecticide.

Conclusions:

• There is a critical need for standardized protocols to accurately assess insecticide resistance in sand flies.
• The CDC bottle test with a Standard Resistance Line (SRL) is recommended for rapid detection of local insecticide resistance and diagnostic time.
• Recommendations for experimental design include using F1 generation sand flies (up to 5 days old), avoiding engorged or pregnant females, and using at least 100 individuals per assay.