A recent study published in the Journal of Medical Entomology by researchers at Virginia Polytechnic Institute and State University (Virginia Tech), led by urban entomologist Dr. Warren Booth, has identified a gene mutation in bed bugs (Cimex lectularius) associated with potential insecticide resistance.
Per Virginia Tech’s online article on the findings, the research was initiated as a molecular skill-building exercise for graduate student Camille Block. It involved analyzing deoxyribonucleic acid (DNA) from 134 unique bed bug populations collected by North American pest control companies between 2008 and 2022. Screening these samples revealed the presence of a specific gene mutation in two distinct populations. Notably, this mutation is the same one known to create resistance to certain insecticides in certain populations of German cockroaches (Blatella germanica) and whiteflies (Aleyrodidae). Further investigation confirmed that all individuals within these two bed bug populations possessed the mutation.
Dr. Booth explains that the resistance mechanism in German cockroaches is linked to a nervous system gene (Rdl) known to confer resistance to dieldrin, an insecticide with the same mode of action as fipronil. While dieldrin has been off the market since the 1990s, fipronil is currently used with great success in consumer flea and tick treatments for pets and in the professional pest control industry for several general household pests. It is important to note that it is not labeled for bed bugs, however.
Dr. Booth theorizes that the observed resistance may be linked to indirect exposure. Residue from fipronil-based pet treatments could be transferring to bedding, inadvertently exposing bed bugs and potentially selecting for resistant populations over time.
PMP magazine reached out to several manufacturers of fipronil-based products for comment on the study’s findings. They unanimously emphasized that a range of effective, labeled solutions are currently available for bed bugs, and because fipronil is not labeled for this pest, it’s essentially a non-issue. The manufacturers also strongly continue to advocate for the established best practice of rotating insecticide formulations and active ingredients to proactively mitigate the development of resistance across all target pests.
The Virginia Tech team’s next steps involve a broader global survey of bed bug populations and an examination of historical samples to understand the prevalence and evolution of this resistance mechanism. Dr. Booth noted that ongoing genomic sequencing efforts, including their recent sequencing of the entire bed bug genome, will be crucial in this research.
About the Author
Heather Gooch is the editor-in-chief for PMP magazine. She can be reached at hgooch@northcoastmedia.net or 330-321-9754.
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