Tick Off

Have you ever been put off using an insect repellant because of the toxic chemicals it contains? This, plus growing fears of resistance to chemical repellents, has prompted interest in plant-derived repellants to ward off ticks and suppress the tick-borne diseases that threaten human and animal health. Ticks make up for limited vision and hearing with a strong sense of smell, but the mechanisms of tick olfaction aren’t well understood. Researchers have discovered the Haller’s organ (pictured under scanning electron microscopy), a sensory organ on their front legs with protruding sensory hairs and two openings, is the key organ for detecting cinnamaldehyde, a component of cinnamon oil known to repel ticks. The team identified a receptor and binding site that specifically responds to cinnamaldehyde, triggering a response through Haller’s organs. Understanding this process is key to developing naturally-derived repellants to help cross ticks off the list of problems.

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

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• Image from work by Ceyan Kuang and colleagues
• Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in PLOS Neglected Tropical Diseases, March 2025