Cat Fleas & Humans: 6 Things You Need to Know!

This is a great reference guide with all you need to know about cat fleas & humans. Find out all about these irritating and hard to remove feline parasites.

Domestic cat with fleas, Cat Fleas & Humans

Itching is one of the obvious flea symptoms

We’ll go over the best practices on how to prevent infestations, how to really get rid of these blood-sucking insects and what to do to keep your furry friend flea-free over time.

Sometimes there is no way to avoid having your cat pick up a flea from the surroundings, for example, just going out and meeting other cats can be enough. Our smallest son started getting bites all over his legs and then his body, not something you as parents take lightly. Getting rid of them was very complicated and required testing quite a few different anti-flea medication options, until we got the right prophylactic program.

Unfortunately, cats are pets that are not only loved by their human companions, cat fleas love them too, for them they are tasty, warm and welcoming breeding grounds.

1- How do you recognize cat fleas?

2- Do cat fleas bite humans?

3- What symptoms do fleas cause?

4- What is the Flea’s Life Cycle

5- How do you prevent flea infestations?

6- What diseases can fleas transmit?


The cat flea (Ctenocephalides felis) is a very small external wingless insect parasite, one of approximately 2000 species worldwide that affect both birds and mammals and require blood meals from their host [1]. At first glance they look like small shiny black dots, they multiply very quickly and in large numbers (a female flea can lay 20 to 30 eggs a day [2]).

If we live with cats, we will always have to include anti-parasite care and include either flea repellents or treatments for them from time to time, especially if they have permission to go outside your house, if they have a garden where they spend a lot of time, or if we take them out regularly. We also should not forget that fleas can also hitch a hike on our clothes, and end up in your house and on your pet.

Along with all the irritation they cause our pets, can they also affect us? Sadly yes, these disagreeable pests can also harm us.

1- How do you recognize cat fleas?

The cat flea (Ctenocephalides felis) Cat Fleas & Humans

The cat flea (Ctenocephalides felis)

These parasites are very small, less than 4 millimeters when they reach the adult stage. Their bodies include two very long and strong hind legs that they use to jump (200 times their length [6]) and four frontal ones that are somewhat shorter, they have a very small head with a mouth designed to pierce skin and suck blood [1], and a big abdomen where they store the blood they suck.

When they are in their larval phase they look totally different, they are like a very small worm, with an almost transparent body, when you look at them under a microscope you can see some “bristles” that actually are sensory hairs on the upper half.

Eggs are laid by the female on various animals that serve as a host: dogs and cats especially, but also rodents, rabbits, ruminants and humans, although in the latter they do not usually complete their life cycle.

2- Do cat fleas bite humans?

The Cat flea (Ctenocephalides felis) is one of the most common flea species after dog fleas. These fleas can bite humans, just as they bite cats. However, unlike cats, these fleas do not stay to live on our bodies, that is, they can bite us, attempt to feed on our blood and leave [4], they do not live and breed on us [3]. They are adapted to live on furry hosts, not hairless ones like humans, they have a hard time attaching to humans and are often seen and killed before feeding [5].

3- What symptoms do fleas cause?

The truth is that the symptoms are the same for both cats and humans and they include the following:

  • Itching. Bites itch because fleas release saliva that includes an anticoagulant into your skin and blood flow that makes it easier for the flea to feed, but it’s a foreign substance and your immune system reacts to it.
  • Swelling. The skin around the bite will swell as part of the allergic reaction.
  • Reddened skin as a result of the bite itself and from the allergy, the flea saliva generates.
  • Injuries and Infections in serious cases, injuries can be caused by you scratching the bites and these in turn can become infected, causing even more discomfort and other diseases.
  • Irritability and discomfort. The bites will continue as long as you host the fleas, they will hurt and itch and the affected area will increase. You’ll want to shower try to get rid of them. You’ll be continuously scratching your skin and hair until it’s over.

Anyway, you can see it’s no fun and you’ll no longer be surprised if our cat seems to be irritable when it has fleas. So it makes perfect sense to help your pet and yourself prevent these infestations and to get rid of them as soon as you detect them.

4- What is the Flea’s Life Cycle

Cat Flea Life Cycle

As mentioned before, fleas are insects and have a specific life cycle that repeats with small variations in all species within this, the largest arthropod phylum (6 to 10 million insect species) [7]. Egg, larva, pupae, adult and the cycle repeats.

In fleas the cycle will include a host, that is, your cat and lacking a furry pet, they’ll bite you too.

You’ll either bring them yourself into your home on shoes and clothes or your cat will hide them in their fur. They start reproducing within 24 hours.

After feeding on your pet’s blood (or yours) adults lay eggs around the house on your furniture, carpets, crevices, in corners and anywhere your cat goes, eggs will be falling off and into the surroundings [8]. Eggs hatch in one to 12 days depending on the temperature [9], warmer temperatures, faster hatching [8]. White worm-like flea larvae come out of the eggs and within 7 to 14 days it will spin a tiny cocoon and pupates. After a week, more or less, an adult emerges from the pupae and starts its search for food and the cycle repeats [9].

5- How do you prevent flea infestations?


Generally, people who care for cats or have cats at home, also suffer flea bites, so basic prevention includes keeping your pet and the place where it lives clean. Comb and shampoo the cat frequently to remove adult fleas before they irritate the pet or lay eggs [9]. A power tip: start shampooing around the cat’s neck before shampooing the body, as fleas will immediately migrate to the head if they notice the water on the body.

In our specific case, we were able to control the flea infestation with Frontline pipettes, whereas other options never really got rid of them, so personally I can recommend them. In general, there are two treatment options, for best results you need to follow both.

On-Cat Treatment

The most effective method to effectively control fleas is on-animal. The cat is treated with a product that attracts the fleas while it moves around the infested parts of the home. Fleas are then killed by contact with spot-on and sprayed products or by sucking treated blood through pills and oral liquids. This treatment also has the added benefit of reducing the number of pesticides used to treat the premises, which concentrates on killing eggs, larvae, and pupae.

These treatments are weight-based and you need to make sure you use the right amount of product. Your vets can prescribe and apply options not available over the counter [1].

Premise Treatment
vacuum clean to remove cat flea eggs

Carefully vacuum the whole house to remove flea eggs

Standard means of control of the pet: Wash bedding and vacuum regularly (especially along cracks and crevices). You can also spray baseboards with flea insecticide. Pay particular attention to areas where the pet frequents. Steam clean carpets and upholstery if necessary. Any dirt that’s collected should be disposed of immediately to destroy fleas and larvae.

There are a number of chemicals and methods (pipettes are popular) to control flea infestations such as the application of lufenuron (Program), imidacloprid (Advantage), fipronil (Frontline),

Carbaryl, (Sevin), resmethrin, Methoxychlor and Malathion are available to the general public. Insect growth regulators available through veterinarians, such as Methoprene (Precor) and pyriproxyfen (Nylar, Archer, Biospot), also are effective [1].

Other things you can use are the anti-flea collars (preferably with safety lock), or anti-flea sprays. Be very careful with these last ones, never buy those that carry permethrins or cypermethrins, as they are very toxic to cats. Furthermore, it is best to apply first in a small area, wait to see if it generates any adverse reaction; if all goes well, then finish off the treatment avoiding eyes, nose, mouth, ears and the genital area.


Take a good shower, wash the clothes you were wearing as well as the house (tablecloths, sheets, the cat’s bed, etc.), and carefully vacuum clean the whole house.

If the bites itch a lot, we can use a natural Aloe vera cream or gel, it quickly relieves the itching.

Aloe vera cream relieves FLEA BITE itch Cat Fleas & Humans

Aloe vera cream or gel quickly relieves flea bite itch

For your hair and/or beard, you can use a flea shampoo (the kind for cats or dogs) there aren’t any specifically for humans or maybe lice shampoo. If you can’t get any, then dish soap will kill your fleas too. Apply it to the hair and leave it there for 10 minutes before combing with a flea comb, then wash it out.

Make sure you clean any combs you’ve used and continue combing your hair in the same fashion for a week after you think they’ve gone away.

Spray yourself with anti-flea spray, or make your own version with 90% boiled water mixed with 10% essential oil as a spray [10].

6- What diseases can fleas transmit?

In developed countries, the diseases transmitted by fleas are relatively minor. International travel and global warming will potentially increase the number of diseases and the number of people and pets affected by them [11].

Bubonic plague

FLEAS CAN TRANSMIT bubonic plague Cat Fleas & Humans

Fleas can transmit Bubonic Plague

It’s a disease that in the middle ages killed almost half the population in Europe. It still occurs in our day and age, but only a few cases where fleas transmit it from rodents to humans and pets in the southwestern USA. It can successfully be treated with antibiotics[11].


Typhus is an infectious disease transmitted by several species of the Rickettsia bacteria, which uses fleas, mites, lice, and ticks as a host and affects humans. Symptoms are recurrent high fever, chills, headache (headaches) and generalized skin rashes.


It is a genus of bacteria that, using fleas, mites, ticks, and mosquitoes, infect humans causing various symptoms: fever, vomiting, nausea, malaise, weakness.

Flea allergy dermatitis (FAD)

An eczematous itchy skin disease in cats and dogs. Symptoms include redness, bumps, pustules and scabs [12]. As a result, animals may develop crusty lesions and may constantly scratch at their skin, often leading to fur loss [11]. In humans it is rare, but we could also have scab wounds and itching.

Fleas can also be parasite vestors, such as tapeworm, that mainly affects pets when they accidentally ingest infected fleas while grooming [11].

Our vets can help & guide you through any flea issues you may have with your cat and pet. Call us at (419)362-9696 or click the button below to get an appointment and the right treatment or solution for your specific flea situation.


[1] Cat Flea, Gale E. Ridge.
[2] Fleascience “Can fleas survive and reproduce on human blood?”
[3] Williams, B. One jump ahead of the flea. New Scientist 31, 37–39 (1986).
[4] Pullen, S. R. & Meola, R. W. Survival and reproduction of the cat flea (Siphonaptera: Pulicidae) fed human blood on an artificial membrane system. J. Med. Entomol. 32, 467–470 (1995).
[5] Fuller, G. K. Observations on flea attachment at low hair densities on man. Journal of Natural History 8, 207–213 (1974).
[6] “Why do flea bites itch so much?”
[7] Insect. – fetched Sept. 8, 2019
[8] The Flea Life Cycle. Pet Basics from Bayer.
[9] Fleas. University of Florida IFAS Extension.
[10] Can Fleas Live on Humans. Metro.
[11] Flea diseases. Ehrlich.
[12] Allergic Flea Dermatitis. Wikipedia.

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