Scientists Unlock Mosquito Repellent Mystery, Paving Way for Safer Alternatives
Jerusalem, February 24, 2026 – An international team of scientists, led by researchers at the Hebrew University of Jerusalem, has solved a long-standing mystery: how certain plant extracts effectively repel mosquitoes. The breakthrough identifies a specific odorant receptor in mosquitoes that responds to borneol, a compound found in camphor tree oils, offering a blueprint for a fresh generation of more precise and safer repellents.
The Science Behind Mosquito Repulsion
For millennia, communities across Asia and beyond have utilized camphor- and borneol-rich plants to deter mosquitoes, even though these insects are strongly attracted to human cues like carbon dioxide and body odor. Until now, the mechanism by which repellent odors override these attraction signals within the mosquito brain remained unclear.
The study, published in Nature Communications, pinpointed a highly conserved odorant receptor, known as OR49, that is specifically tuned to detect borneol in several major mosquito species, including those responsible for spreading dengue, Zika, and West Nile virus. Activation of this receptor triggers a dedicated neural pathway, causing mosquitoes to actively avoid the source of the odor. Researchers confirmed OR49’s crucial role by genetically disabling the receptor, which resulted in mosquitoes no longer avoiding borneol.
Implications for Mosquito Control
Understanding how mosquitoes sense repellents is increasingly important as resistance to conventional chemical repellents grows and concerns about their environmental and health impacts rise. By targeting the insect’s own sensory wiring, future repellents could be more precise, longer-lasting, and safer for both humans, and ecosystems.
The findings also provide historical context. Camphor- and borneol-rich materials from Borneo were historically traded along the Maritime Silk Road for their fragrance, medicinal properties, and insect-repelling capabilities. The newly identified OR49 pathway explains their enduring effectiveness.
New Approaches to Mosquito Management
Beyond understanding the mechanism of borneol’s repellent effect, researchers at the Hebrew University of Jerusalem are also exploring innovative mosquito control strategies. A recent study led by Doron Zaada and Prof. Philippos Papathanos introduced a gene-editing method to separate male and female mosquitoes, a critical step for large-scale mosquito control programs. This new method utilizes CRISPR gene editing to create a strain where females are distinctly yellow, allowing for automated sex separation.
researchers have developed a safe new method to prevent mosquito bites using a skin coating made from naturally occurring cellulose nanocrystals (CNCs). Applying this thin CNC coating to human skin decreased mosquito feeding by 80%. The combination of CNCs with the mosquito repellent indole further enhanced its effectiveness, reducing egg-laying post-exposure to mammalian blood by 99.4%.
Looking Ahead
These advancements from Hebrew University researchers represent a significant step forward in mosquito control. By combining a deeper understanding of mosquito sensory biology with innovative genetic and material science approaches, scientists are paving the way for more effective, sustainable, and safe strategies to combat mosquito-borne diseases.