This article will explain the difference between dog fleas and cat fleas. Is one worse than the other? Are cat or dog fleas harmful to humans? And what exactly is the difference between a cat fleas vs a dog flea vs a human flea?
We’ll answer all the above, and more.
Let’s dive in!
Cat Flea vs Dog Flea
In both the UK and the USA, the most common type of domestic flea is the cat flea, whose “proper” (latin) name is Ctenocephalides felis. Yes really. That’s the sort of sh*t we had to deal with at Vet School.
When I say “domestic” flea, I mean a flea which is found in and around human dwellings. Whereas a non-domestic flea would be something like the UK’s hedgehog flea, Archaeopsyllus erinacei.
Contrary to its name, the cat flea is actually the most common type of flea to affect both cats and dogs. So, if your dog has fleas, it’s very likely that these are in fact cat fleas. Dog fleas have a different latin name, Ctenocephalides canis, and are actually an entirely different species to C. felis.
Dog fleas are way less common than cat fleas, especially in the USA (also here in the UK). In fact, we’re talking about 90% of all fleas found on dogs in the UK being cat fleas, and the figure in the USA is even higher.
In the same way that cat fleas can feed on dogs, dog fleas are able to feed on cats…but C. Canis is a fussier eater than C. felis. Although it has been found to occasionally feed on cats and humans, this is unusual. The dog flea generally prefers to stick to dogs.
If you kill a cat flea and a dog flea (as you most certainly should), stick both on a glass slide and examine them down a microscope, you will notice that there are some microscopic difference between the two. However, to the naked eye, there is no way to tell them apart. You cannot tell just from looking whether your dog has cat fleas. But – especially if you live in the USA – you can make the assumption that your dog probably has cat fleas.
Can Cat Fleas Affect Humans?
As a vet I’m commonly asked whether cat fleas can get on humans (usually by itchy owners who arrive with the tell-tale small red spots of a flea bite on their arms or legs). The answer to this question is yes, sort of, and also no, not really:
Whilst cat fleas are able to bite humans, and will happily view us as a drive-by snack, they can’t actually live on us.
Although studies have shown that cat fleas can survive exclusively on human blood under laboratory conditions, in real life, cat fleas are not able to live on humans for one main reason: we simply aren’t hairy enough.
Our distinct lack of fluff means we don’t offer the warmth, protection and camouflage that fleas can find on our feline and canine housemates. Cat fleas also have some degree of “host specificity” in terms of what blood they prefer to consume; if given the choice, they’ll opt for cat blood for preference, followed by dog blood, and finally if neither of the above are available, they may resort to biting a human, in a pinch.
Fleas are also way less good at reproducing (laying eggs) when they are feeding on humans. This is likely because a flea needs to feed for a significant amount of time, at least 8 hours (some sources suggest 12 hours when a human is the meal), before they are able to lay eggs…and really, because we humans are fairly bald, it is highly unlikely that a flea will be able to feed uninterrupted for this length of time on a human without being found and – hopefully – squished without delay into a small brown puddle.
Be aware, that immature (baby) fleas, ie, those who just recently hatched and have not yet reached an adult stage, do not actually live on dogs, cats or people, but rather they live freely in the environment and feed on detritus (such as dandruff, shed skin cells, and – super gross – the faeces of adult fleas). Nor are flea eggs or pupae found on us or our pets, but rather these are found in the environment….typically in pet beds, sofas, carpets and the cracks between wooden flooring.
A full overview of the life cycle of a flea can be found here, for those who are interested:
What About Actual Human Fleas?
I’ll start by pointing out that a variety of different species of flea can feed on humans, but typically, when we use the term “human flea” we are talking about Pulex irritans, which is also frequently referred to as the “house flea”.
This flea is not common in developed countries or industrial areas, but may occasionally be found in parts of Europe and the USA, especially rural areas. It is believed to have originated in Central and South America, although today, it seems to be rarely found in these regions.
The human flea, like its canine and feline counterparts, is not too fussy when it comes to choosing where to grab a bite, and will readily accept pig, dog, cat, rabbit, rat or guinea pig blood (amongst other delicacies). In fact, contrary to the name “human flea”, pigs are thought to have been the original host for P. irritans, and likely remain it’s preferred meal, if a variety of food sources are on offer.
Due to it’s somewhat indiscriminate eating habits, and specifically it’s readiness to hop from human to rat and vice versa, P. irritans was one of the key species involved in the spread of bubonic plague (caused by the bacterium Yersinia pestis), although the Oriental rat flea (Xenopsylla cheopis) was more to blame.
Fleas of all kinds (cat, dog, human and other) remain important spreaders of a variety of diseases; more information can be found here:
Finally: What’s Worse: Cat Fleas Or Dog Fleas?
Ah yes, that age-old question – what’s worse?
Well, to be honest, when it comes to sharing your home or your pet with fleas, it doesn’t really make much difference whether you happen to have crossed paths with cat fleas or dog fleas. Both will cause the same annoying clinical signs for your poor pet, and both have potential to give you a nasty bite.
On the positive side, both are eliminated in the same way – by treating your pets and your home – and so it really isn’t necessary to identify whether you have cat fleas or dog fleas before getting started with eradication methods.
I plan on doing a full blog post on flea eradication in the near future, and will link it here when finished. But in the meantime, if you need help with a pesky flea infestation, I suggest you check out the following two resources:
…And please, don’t even bother faffing around with the natural remedies like baking power and lemon juice (as if that was ever going to work). And don’t be that person that puts tea tree oil or witch hazel on your dog. Your dog is not a teenage girl with acne. Your dog is a dog. And besides, it’s not going to work.
Fleas are a real health hazard for you and your pet. Use prescription flea treatment dispensed from your vet, and a proper house treatment spray, OK?
It’s really not worth fannying about with anything else.
And, in case it needs to be said, as a vet I strongly, strongly recommend that you keep all pets in your household protected against fleas at all times. Even in winter (fleas love central heating). This is for the sake of your pet’s health and comfort, and – as we’ve discovered – for the sake of your health and comfort, too!
Still have questions? Stick ’em in the comments, and I’ll get back to you.
Want to read more by me? Here’s a few suggestions:
- Why is My Dog Dry Heaving?
- Top 5 Best Calming Treats for Dogs
- Is there an Alternative to Apoquel for Dogs?
- Can Dogs Eat Raw Chicken – And Raw Chicken Bones?
- When To Euthanize A Cat With IBD