Overview

Tick bites range in severity from being harmless but annoying, to being the connection to potential life-threatening infection. Despite this, there are different ways in which to prevent ticks from biting you. These methods range from chemical interventions to physical barriers to stop ticks from contacting you at all.

What are tick bites and how dangerous are they?

Ticks are parasitic arachnids (meaning they are closely related to spiders) that feed on the blood of mammals, including humans. Tick bites generally are not that painful or even noticeable to some and you most likely experience itchiness around the bitten area, which goes away after a couple of days. Bites from ticks with no associated disease are not considered dangerous but rather unpleasant, so you may wish to prevent it from occurring.¹

Bites can however become more dangerous if the tick is carrying a disease (more specifically, the pathogen that causes the disease). In these cases, ticks are known as vectors, the vessels for transporting the pathogen, which itself is typically bacteria. Some examples of the diseases that ticks can transmit are:

• Babesiosis (caused by Babesia microti), which causes muscle and joint pain, nausea, and vomiting²
• Lyme disease (caused by Borrelia and transmitted by nymphal (the life cycle stage before adult) ticks), which can lead to arrythmia (irregular heartbeat), fever, and facial paralysis³
• Ehrlichiosis is associated with headache, fever, and muscle aches (caused by Ehrlichia and Anaplasma)⁴
• Powassan virus (caused by the Flavivirus virus) is a very serious infection that leads to encephalitis (inflammation of part of the brain) that can result in death⁵

It can be difficult to directly target the bacterial species responsible for these conditions, so the most effective method of prevention is to target the vectors (in other words, the ticks). 

Clothing

If you are in an environment where tick presence is inevitable, you can minimise your exposure to the parasites by wearing long-sleeved tops or trousers and avoiding shorts. Ticks tend to bite you on the limbs or the neck, so covering these areas can limit the chances of being bitten.

While outdoors, synthetic materials such as nylon, polyester, and Lycra (in sportswear) are highly protective of bites but also have pores to allow your skin to properly “breathe” or ventilate. Some ticks may prey on other species and not just humans, so wearing appropriate clothing can limit interspecies transmission.⁶

Bright clothing may help ticks be more noticeable if they do show up. While they are very small, they are not microscopic, so you should be able to see them with the naked eye and even remove them yourself. Fine tools like a pair of tweezers should be sufficient.

Chemical interventions

DEET

Diethylmetatoluamide, more commonly referred to as DEET, is a chemical that is known to be highly effective at repelling bug pests such as fleas, mosquitoes, ticks but also leeches.⁷ DEET affects the antennae of ticks, an organ they use for sensation, blocking a specific chemical receptor. This receptor is used to detect L-lactic acid, a substance that while not abundant in humans, is produced at an adequate level for pests like ticks to identify us and feed. DEET blocks these receptors so ticks cannot identify humans (or other mammals) and therefore less likely to bite you.⁸

Commercially, DEET is aerosolised and can be bought as a spray for your clothes, belongings, and even on your skin.

There have been occasional reports of side effects with excessive DEET usage. These adverse effects are skin irritation, agitation, low blood pressure, loss of coordination, and even seizures. Due to this, it is recommended to primarily use DEET spray on clothes and not too much on the skin, alongside other preventative measures to limit its use.⁷

Picaridin

Another chemical that is widely used as a tick repellent is picaridin which has a different mechanism of action to DEET. Picaridin is believed to interact with the tick’s olfactory system (relating to the sense of smell) by binding to several different receptors. This contrasts DEET which targets ticks’ detection of one certain chemical we humans produce, as picaridin essentially removes any sense of detecting humans (or anything). Picaridin has been shown to be slightly more effective than DEET in repelling mosquitos, but the same is unconfirmed for other pests like ticks.⁹

While ticks do have eyes, they rely on odours that we release to move towards us so targeting their olfactory system is more important. Picaridin is commercially available as a spray or a lotion that can be applied directly to the skin. To prevent overuse or skin damage, it is typically sold at a 20% concentration.⁷

Excessive use of picaridin can cause skin irritation but this is uncommon. Sprays have the risk of accidental entry of the chemical into the eyes which also can lead to irritation. Accidental ingestion of picaridin has been shown to affect the kidneys and overall body weight, however, this is in a rare worst-case scenario.⁹

Permethrin

The strongest insecticide against ticks that is commercially available is permethrin which is sold at concentrations as low as 0.5% due to how strong it is. Because of this, permethrin can remain on clothing after several washes. As permethrin is an insecticide, it kills ticks. This is done by blocking sodium channels that neurons rely on for survival (not limited to olfactory sensing), making this substance the strongest and most potent option out of the three chemicals described in this article.

The strength of permethrin corresponds to its potential danger if misused. It should only be used on objects like clothes or insect nets and not directly on the skin, despite it being sold in diluted quantities. The main unintended effects on people are skin irritation, redness, and swelling that can take the form of rashes or chemical burns if more serious. If accidentally inhaled, it can irritate the throat and lungs and cause fatigue or dizziness. In any case, where accidental inhalation (or ingestion, which is significantly more serious) occurs, you should seek immediate medical attention.¹⁰

Environmental maintenance

When not feeding on human hosts, ticks tend to inhabit vegetation including grass. Long grass typically causes a greater risk of tick interaction since it brushing onto you provides an opportunity to move onto you or your clothes, even if your exposure time is short. Keeping your lawn short can reduce the risk of tick interaction if they cannot reach you since ticks cannot fly or jump.¹¹

This concept can extend to any tall bush or shrubbery that could be a tick habitat. These measures should only be considered if you do have an existing tick problem and need to rule out the sources of the issue.

Physical barriers can be considered if there is a tick problem in your garden, such as having an area without grass (such as gravel, sand, or wood chips). These are not suitable habitats for ticks so they will stay in grass/plant-containing areas.¹² Paving slabs are also effective.

Insecticide-treated nets

Bed nets are mesh veils that typically surround beds or cover windows to block pests, typically mosquitoes. This creates a physical barrier to prevent bites, which has been shown to be highly effective at blocking the transmission of tick-borne infections. These nets may also be treated with insecticides or insect repellents to increase their effectiveness.¹³

This combination method, commonly referred to as insecticide-treated nets (ITNs) is fairly common and works well for tick bite prevention since the holes in the mesh may be too large to keep out the ticks. ITNs can also be considered useful for keeping out larger bug pests like mosquitoes.

Tick collars

While it has not been mentioned so far in this article, your pets (namely cats and dogs) can be vulnerable to ticks. This could be due to their hygiene or they may have been in an area with an unusually high density of these parasites.

Tick collars are covered in acaricides (chemicals that specifically kill ticks and mites) which are designed to leak into dog hair to surround your pet so ticks die upon contact. These collars are marketed for dogs since they do not tend to groom themselves often, but cats can also use these products if they have a persistent tick problem.¹⁴

Summary

The different approaches used to prevent tick bites can be broadly categorised as being either chemical or physical. These methods such as the use of repellents and ITNs can be used alone, but it is better to use a combination to maximise success. In terms of repellents, there are a few options to choose from – aside from their differences in mechanism of action, they vary based on strength but also the potential adverse effects they can bring with misuse. Environmental interventions are more time- and effort-consuming, however, these can bring positive, long-term effects regarding reduced tick problems, should such problems be present within your own home.