Donkey Skin May Be a Secret Weapon in the Fight Against Ticks and Lyme Disease

Nothing sends a shiver down the spine like finding a tick latched onto your skin after a hike. But beyond the nausea-inducing idea of being host to a blood-sucking parasite, the consequences of tick bites can be dire depending on the circumstances. This is because a few tick species carry diseases that can be passed on to humans — the most notable one is Lyme disease.

An unlucky encounter with a deer tick (Ixodes scapularis) could leave you with Lyme disease. Fortunately, a study published in PLOS One has advanced a new way to repel deer ticks with a surprising solution: donkey skin. More specifically, a naturally occurring compound secreted by donkey skin can stave off deer ticks, showing potential to be an effective alternative to existing repellents.

The Dangers of Deer Ticks

Not all ticks carry diseases, but deer ticks (also known as black-legged ticks) are one of the species to watch out for. These ticks span across the eastern U.S, but they’re most likely to carry Lyme disease in the Upper Midwest and Northeast. A 2024 study found that half of all adult ticks in the Northeast carry the bacteria that cause Lyme disease. 

Deer ticks don’t harbor Lyme disease bacteria at birth, but rather, receive it from infected hosts that they feed on, usually small rodents. True to their name, adult deer ticks also commonly feed on white-tailed deer, a reliable source of blood. However, deer do not get infected by Lyme disease and can’t transmit the bacteria to ticks.

Most hikers are probably used to warnings about tall grass, where ticks search for legs to cling onto. They get a hold of skin not by jumping or flying, but by “questing”: This is when they climb plants and reach out with their front legs, patiently waiting for a host to attach to. 

Once a tick has attached itself to the skin, it sucks blood for multiple days and eventually becomes swollen, engorged enough to stop feeding. 

Infected saliva from the tick can spread Lyme disease to humans during this process, but infection isn’t instantaneous. It generally takes at least 24 hours for an attached tick to transmit infection. 

Read More: What Is Lyme Disease, and Why Are Cases on the Rise?

A Natural Tick Repellent

Tick bite prevention usually comes in the form of DEET (applied directly on the body) and permethrin (applied to clothing and gear). However, researchers involved with the recent study say that donkey skin could be the next step forward in fighting tick bites. 

Donkeys and horses secrete substances through their sebaceous glands (which are on most mammals’ skin) that can affect how other animals interact with them. While horses are vulnerable to ticks, donkeys secrete a special compound known as (E)-2-octenal that is able to repel ticks. Previous research has shown that when horses are treated with octenal, their smell is masked and they can resist ticks just like donkeys. 

How Donkey Skin Can Prevent Tick Bites

This superpower of donkey skin, the researchers say, may even have applications for humans. 

“It’s one of the different smells that you find on a donkey that you don’t find on a horse,” said lead author Eric Siegel, a doctoral student at the University of Massachusetts Amherst, in a statement. “So, to ticks, the horse doesn’t smell like the host they’re used to. The ticks don’t like it, and so they won’t feed on it. Our assessment that we can repel ticks with this compound means that, in theory, we could either put it on ourselves or put it on dogs, and the ticks will not want to go near it.”

The researchers confirmed the effectiveness of octenal by testing how it limits a tick’s movement. According to the press statement, they were able to “prevent deer ticks from moving from point A to point B” when placing octenal between the two points. 

The researchers are now working to develop a deer tick repellent with octenal as the active ingredient. They also believe the compound could also be used to control deer tick population in nature and potentially replace pesticides.

Read More: As Lyme Disease Cases Grow, Treatment Makes Progress to Stop Infection

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• PLOS One. Exploiting a natural instance of vertebrate-posed chemical aposematism for tick bite prevention: Repellency of Ixodes scapularis with (E)-Oct-2-enal

• CDC. Where Ticks Live

• Dartmouth College. In the Northeast, 50% of Adult Ticks Carry Lyme Disease

• CDC. Lyme disease

Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.

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