Ticks are a common problem for anyone who spends time outdoors. After hiking, gardening, or mowing, many instinctively check for ticks. These tiny parasites can carry dangerous diseases like Lyme and anaplasmosis.
Most people use DEET to repel ticks and other biting insects. But DEET can feel sticky, smell unpleasant, and raise safety concerns. Many want a natural alternative that still works well. Lemongrass has shown promise as a natural repellent. Now, researchers have found another option—this time from donkey skin.
A new study shows how a compound called (E)-2-octenal, secreted by donkey skin, repels deer ticks. The research was published in PLOS One and conducted by researchers at the University of Massachusetts Amherst.
Deer ticks, also known as Ixodes scapularis, are the main tick that bites humans in the U.S. (E)-2-octenal stops ticks from moving toward treated areas. It was even more effective than DEET in some cases.
How Did Researchers Test (E)-2-octenal as a Tick Repellent?
The study tested (E)-2-octenal against Ixodes scapularis. They compared its effects to DEET, the current gold standard. Ticks were exposed to 20% solutions of each repellent.
Researchers used a filter paper test to study behavior for 10 minutes. Ticks moved slower and wandered more on treated surfaces. Both repellents were more effective than ethanol, the control.
Male ticks were more affected by both DEET and (E)-2-octenal. Female ticks showed less change in speed or direction. However, the donkey compound worked significantly better than DEET on males.
The study tested 300 adult ticks—half male, half female. Ticks exposed to ethanol moved straight to the target zone. They showed no hesitation, posture change, or direction shifts.
In contrast, ticks exposed to DEET or (E)-2-octenal showed clear avoidance. Many paused, raised their front legs, or turned away. (E)-2-octenal caused the most zig-zagging near the treatment zone.
DEET-exposed ticks often froze instead of fleeing. They stayed in the drop zone when repelled. Neither compound showed signs of irritation or caused death within 24 hours.
Why Is (E)-2-octenal an Effective Tick Repellant?
Ticks reacted to (E)-2-octenal before touching treated surfaces. The compound’s high vapor pressure likely explains this effect. Researchers believe it may act as a spatial repellent. More research is needed to confirm how it works.
Over time, ticks seemed to tolerate the treated zone. This tolerance was more common in female ticks. Further testing could explain how and why this resistance develops.
Researchers think (E)-2-octenal acts as a true repellent. Even in a scent-free lab setting, ticks moved away from it. Still, the compound might also confuse ticks or block host signals. Future studies will help clarify these effects.
Scientists don’t yet know why animals like donkeys emit (E)-2-octenal. It’s also unclear how ticks detect or respond to it.
We still don’t know how far ticks can sense the compound. We also don’t have measurements for what concentration is most effective. It’s unknown whether it can be safely blended with other repellents.
Conclusion
Tick populations are spreading north and reaching new areas due to climate change. More people are now at risk from tick-borne diseases.
Donkey skin compound (E)-2-octenal shows strong potential as a repellent. It performed as well or better than DEET in lab tests. This discovery could lead to safer, natural protection from tick bites.
Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.
Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.
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