What Attracts Fleas to Humans and How to Protect Yourself

Fleas are nasty little pests that can range from being a mild annoyance to a serious health risk. They often give our pets a hard time, but in my experience, they can also affect us, humans, too.

There are three main factors that attract fleas to humans. Warmth, movement, and the odor of carbon dioxide that we exhale. Fleas can also be attracted to some other smells that humans emit. However, fleas are normally only attracted to humans if they have not yet found a more suitable host.

The thought of “contracting” fleas is not a pretty one. Not to worry! Let’s talk more in-depth about what fleas are attracted to, the dangers associated with flea bites, and what we can do to repel fleas from us, our pets, and our homes!

What Attracts Fleas to Humans?

Even though humans are not ideal hosts for the majority of flea species, in the absence of any more suitable hosts, they will still bite us. This is due to a few basic survival instincts that fleas possess. Let’s go over these in some more detail.


Fleas are very driven by their stomachs and the need to fill those stomachs in order to survive. Can’t really blame them for that!

Fleas need to feed on warm-blooded animals so naturally if a flea detects a heat source, such as a human, it will be drawn towards said heat source in the hopes of finding a nice warm meal.

Additionally, there is a reason why fleas tend to prefer warmer climates and why flea season tends to be in the warmer months of the year.

Fleas need to stay warm for their bodies to function properly but as they are cold-blooded insects, they are unable to regulate their own body temperature.

Therefore, finding a warm place to stay i.e. a warm-blooded host is all the more important to them.


The next thing that fleas are drawn to is movement. While fleas do not have the best eyesight, they do have photoreceptors that can detect changes in light. Adult fleas are phototactic creatures which means they move towards the light.

While fleas are attracted to light, they are even more attracted to sudden changes in light level.

Changes in light level signify that a potential host may have just passed by and cast a shadow or obstructed the light in some way.

For this reason, flea traps that use light to attract fleas (which are fairly common) are more effective when the light is intermittently switched off and on again.

Something worth noting is that while adult fleas are attracted to light, flea larvae are drawn to darkness. Hiding away in the dark while in this more vulnerable state makes sense.

Scent Such as Carbon Dioxide (CO2)

One of the flea’s strongest senses is its sense of smell and they use this to seek out any potential food sources.

Given that larger animals expel carbon dioxide when they exhale, the scent of CO2 is a great indicator that a potential host is nearby so fleas will follow their noses to the source.

Fleas are also attracted to certain other aromas such as the smell of blood.

Luckily, they are also repelled by some scents such as citrus, rosemary, vinegar, witch-hazel, and many more. These scents can be used to our advantage in keeping fleas away. More on this later.

Do Fleas Live on Humans?

If you’re reading this article, there is a good chance that you are aware that fleas can (and do) bite us humans, but can fleas actually live and thrive on humans?

There is only one species of flea named “Pulex irritans” that is known to live on humans. However, there are over 2,500 species of flea worldwide that cannot. Humans don’t make good hosts for fleas due to a lack of warm, dense fur or feathers that fleas use for shelter in order to reproduce.

Fleas need to feed and remain on their hosts for longer durations to successfully find mates and breed. They also need warm temperatures to do so.

Many mammals, including cats and dogs, have a slightly warmer body temperature than us humans which may also be a contributing factor to most flea species preferring these animals.

The Pulex Irritans species of flea is better adapted to live undetected on humans due to their flat bodies and ability to burrow under the skin! They can also reproduce more quickly.

For this reason, Pulex irritans is also known as the “human flea.” However, despite this name, it is often found on a variety of animals including (but not limited to) badgers, foxes, coyotes, bobcats, skunks, raccoons, opossums, certain bats, rats, chickens, and pigs.

Fortunately, “human fleas” do not thrive in urban areas and are fairly localized across the globe. In the states, they are typically found in the south and midwest.

While it is still possible to get fleas from your house pets, it is not common. Cats and dogs typically attract specific species of fleas that do not live on humans. So, although you may still get bitten by these fleas from time to time, for the most part, you can rule out “contracting” fleas from your pets.

Why Do Fleas Bite Me and Not Others?

If you tend to get the brunt of the flea bites in your family or household, you probably wonder, why you?

While no conclusive research has been carried out, there are a few potential reasons and theories as to why fleas are more attracted to certain people than others.

Fleas may be attracted to certain humans because:

  • They exhale more CO2 than others
  • Their chemical makeup or aroma is more appealing to fleas
  • They are in closer proximity to infested animals or flea hotspots
  • They have more exposed skin particularly around the feet and ankles
  • They radiate more heat than others

There is also speculation that fleas may communicate with each other. If this is the case then it is possible that once you have been bitten by one flea, it may somehow communicate the fact to other nearby fleas. This may encourage multiple fleas to attack one person in particular while others are left unscathed.

It’s also worth noting that some people tend to have a worse reaction to flea bites than others so this may also make one feel as though they are being attacked worse than others.

Health Risks Fleas Pose to Humans

The majority of the time, other than the expected irritation, a flea bite is nothing to worry about. However, some health complications can arise from being bitten.

As with any open wound, flea bites may become infected. Signs of infection include:

  • Intense pain at the site of the wound
  • Excessive swelling or redness at the site of the wound
  • Swollen glands

If you notice any of these symptoms, you should see a doctor.

Fleas can also transmit diseases such as:

  • Cat scratch fever
  • Typhus
  • Plague
  • Flea-borne spotted fever

It is also possible to contract other parasites such as tapeworm if fleas are ingested. For more information on these diseases, and parasites check the CDC website

Some people may also have allergic reactions to flea bites such typically these are not severe allergies like hypersensitivity or flea-bite dermatitis. Nevertheless, if someone has been bitten and then suffers from nausea, has swelling of the lips or face, or has difficulty breathing, they should seek immediate medical attention.

8 Ways to Protect Yourself From Fleas

As with most problems in life, prevention is better than cure. Once you already have a flea problem, getting rid of it is a long grueling process. Believe me, I’ve been there!

No single solution works as a magical silver bullet. Using a multifaceted approach is the best way to combat fleas. Here are several things you can do to help prevent fleas from causing you issues.

1. Check and Treat Your Pets for Fleas Regularly

If you are a pet owner then I strongly recommend treating your pets first and foremost before implementing any other preventative measures.

Your animals are by far the most likely to contract fleas and bring them home which can lead to a nasty infestation. Before you know it, everyone in your house may be itching and scratching.

There are plenty of methods and treatments to keep your pets flea-free, such as anti-flea collars, oral treatments, flea combs, etc.

My preferred method of keeping my many pets flea and tick-free is to use a topical or “spot-on” treatment such as Frontline (Amazon). In my opinion, this is by far the most effective and stress-free approach.

You apply it to the back of your pet’s neck and then it dissipates into your pet’s natural skin oils. This not only repels fleas but will kill any that decide to chow down on your pet for up to a month.

Eliminating your pet as a potential food source will significantly reduce the chances of flea infestations at home.

Check your pets over every so often, especially If your pets have been out and about. Fleas tend to be found around your dog’s neck, shoulder blades, belly, groin, and around the base of their tail. If you are always on the lookout, you should be able to catch the problem before it escalates.

2. Stay Away From Flea “Hot-Spots”

A good way to avoid fleas is to steer clear of areas where they are typically found.

Admittedly, fleas can be found almost anywhere but they tend to be more prevalent in areas where wild animals live and particularly on wild animals themselves. Avoid woods, long grass, woodpiles, and damp sheltered areas.

Unfortunately, these are also the types of areas that our pets, particularly dogs love to explore. However, if you have pets that have not been treated against fleas you should also keep them away from these places.

3. Keep Covered Up

If you do go out to the places where fleas are common, one way to prevent yourself from getting bitten is to simply stay covered up.

Keeping your ankles and feet covered is especially effective as these are the areas that fleas will usually jump onto and attack the most.

If possible, you should wear long socks and even keep your pant legs tucked into the tops of your socks or boots. Fleas cannot bite through clothing.

4. Use Flea Repellent Sprays

When venturing out to an area with a high flea population, there are also bug repellant sprays for use on your person. These products are great for repelling fleas and many other pests such as ticks, gnats, and mosquitos.

There are many different products available, some use more natural ingredients than others depending upon what you are looking for. Always use an EPA registered repellent as they use ingredients that have passed various health risk assessments.

I recommend using this EPA registered bug repellent spray (view on Amazon). It’s a DEET (diethyltoluamide) based product. DEET was developed by the US army back in 1946. It was designed specifically for use by troops that were patrolling in the jungle and has been used in a wide range of bug repellents ever since.

Many bug repellent sprays say they can be used directly on your skin. Nonetheless, I would always use caution when applying them for the first time.

Even the more natural formulas that are designed for sensitive skin, can give a small percentage of people adverse reactions. These may include itchy, red, and blemished skin in areas where the product has been applied.

Therefore I suggest testing a tiny amount of any product on a small area of your skin before full application.

There are also many bug-repelling sprays for use around the home (view on Amazon) that can be used to prevent fleas from settling in.

5. Wear Permethrin Treated Clothing

Permethrin-treated clothing (view on Amazon) has also been utilized by the military to prevent troops from being infected by disease-carrying insects and arthropods, such as mosquitoes, ticks, and fleas.

Permethrin binds strongly with clothes that have been properly treated and will remain in fabrics for many, many washes so you don’t have to reapply bug repellent every time you go on a trip.

You can also purchase 0.5% permethrin sprays and use them to treat your outdoor gear such as clothes, tents, and sleeping bags. Again just check any products you use have been EPA approved.

The effective bug-repelling lifespan of home-treated fabrics is not as long as commercially treated, store-bought clothing but can still last up to 6 weeks or 6 washes making it another great way to protect yourself long-term, especially if you like to go camping.

6. Use Ultrasonic Flea Repelling Devices

A relatively new concept for repelling fleas and other pests is to use an ultrasonic pest repelling device (view on Amazon). These products emit a high-frequency audio signal that cannot be picked up by the human ear. This signal deters many pests, including fleas.

The beauty of these products is that you can just plug them in and forget about them. No intruding odors or mess to worry about. They are energy efficient too so you don’t have to worry too much about electricity usage.

There are also battery-powered versions and some that can be fitted straight to your dog’s collar for use when out and about.

7. Keep Flea Repelling Plants

As previously stated, fleas are repelled by the scent of many different natural plants.

Non-toxic flea repelling plants include:

  • Catnip
  • Chamomile
  • Chrysanthemums
  • Lavender
  • Lemon Grass
  • Marigold
  • Mint
  • Rosemary
  • Sage

Many other plants will do the trick too but the ones that I’ve listed above are relatively safe to keep around pets who might ingest them.

Flea repelling plants are most effective if kept near the entrances to your house or in places that your pets hang out the most.

If you are thinking about planting some of these in your garden then it’s worth doing a little research beforehand. For example, mint is considered invasive as it can quickly take over your garden. It needs to be grown in a pot or have its roots restricted in some other fashion.

8. Vacuum Carpets and Wash Bedding Regularly

Given that fleas and their eggs will often drop onto carpets, bedding, and upholstery, cleaning these things regularly can prevent any potential outbreaks from getting out of hand.

Vacuuming carpets and emptying outside will remove any eggs that may potentially hatch. Hot washing or tumble drying bedding (especially pets bedding) and upholstery will also kill off fleas at any stage of the life cycle.

Getting Rid of Fleas

If you find that you have a flea infestation at home, you can implement some of the previous suggestions but you should also do the following:

  • Bathe yourself/your pets with plenty of soap
  • Wash and tumble dry bedding particularly your pet’s
  • Wash upholstery that fleas may have infested
  • Use diatomaceous earth in and around your home
  • Vacuum daily for 2-3 weeks

For a more extensive guide on how to implement these suggestions for getting rid of fleas, please check out my article Child-Friendly Flea Treatments That Actually Work. Whether you have children at home or not, it details steps that I would personally take and have taken to successfully eliminate flea infestations.

Mark Ingram

Thanks for taking the time to read this article. I hope that it was informative and useful in some way. I love all of my pets and their care is paramount to me. I hope that my writing will help others in caring for their pets also.

Recent Posts