why do fleas sometimes cause infestations but other times stick to the pets they entered the home on?

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sorry if this isn’t biology. not sure.

why do some get huge flea infestations from coming into contact with animals with fleas while others have pets with fleas that pretty much seem to stick to the animals?

i live with cats and a dog that get fleas. i give them flea baths/treatments and use flea home sprays to keep it under control, but they always come back in some capacity. the dog unfortunately has to deal with them more than the cats — she’s not my responsibility, but her owner neglects her so i do what i can to tame the fleas when i have the time.

anyway, the thing is that i never see fleas just hopping around on my couch, or mingling in my bed sheets, or bouncing about in the carpet. i definitely never see them on my own body, let alone get bitten by them. the only time they’ll leave my cats is if i happen to see one in the perfect positioning for me to kill and it ends up literally slipping through my fingers. or, if i’m spraying my cats down in flea spray, sometimes one or two will pop away from their wet bellies. or, when i’m bathing them, there might be a couple on my clothes when i’m done. whatever the case, the fleas never multiply and take over my house, my bed, or my body.

on the other hand, i heard a woman talking about a friend that gave her fleas the other day. the friend brought her dog into the woman’s apartment, it scratched its ears a lot and scooted its butt on a rug, and voila, a million fleas jumping jumping when the friend left. they ate her up in the middle of the night and had even taken over her baby in her cradle, who was screaming and slapping herself madly. interestingly, her boyfriend, who slept in the same bed as her, was unaffected by the fleas.

they left, and before entering the hotel room they would stay in temporarily, they meticulously treated themselves, the car, and the apartment. the next night in the hotel, the woman woke up to a live flea on her pillow. it took her a while to finally become flea-free.

so why is it that some can live with flea-having animals just fine, but others get horrible infestations? are there, like, different bloodlines of fleas or something? do i need to worry about my animals’ fleas suddenly starting to fiend for human blood?

edit: the woman who got the flea infestation and i live in the same city. don’t know if that matters.

In: Biology

2 Answers

Anonymous 0 Comments

IME, flea infestations happen when the pet doesn’t live in the home. IE the flea ridden pet was there and brought in the fleas, but then left. Fleas are then left without a host, so they bite humans. When you have a untreated pet, the fleas just eat the pet and you really don’t notice them that much, except for the occasional scratching. Also, eggs can stay dormant for a very long time, so it is hard to get rid of them once you have them. Fleas don’t really like humans so if they have another option as a host they will rarely affect a human, unless like you described where one happened to get knocked off the pet right where you were watching.

Anonymous 0 Comments

A flea infestation is 5% on the pet and 95% in the home. Even if you do not see it the infestation is there. Once the flea lifecycle starts it takes 3 months of consecutive treatment (of the animal) for the lifecycle to die off. 5% of the infestation is on the animal and 95% of the infestation lives in carpets, baseboards, furniture, bedding, any nook and cranny they can fit really. I’m not just talking about adult fleas but their eggs and larvae and pupae (the part of the infestation you don’t generally see). They make powders like FleaBusters that you can sprinkle in these areas to treat them.
Dogs and cats should be on prevention year round. If you’re constantly dealing with fleas the vet can provide prescription strength products that take care of fleas for 30 days to 3 months at a time depending on the product. If that isn’t feasible OTC Seresto collars last for 8 months and are $40-60 dollars (I have seen fleas resistant to them though).

ETA: most flea shampoos are harsh and irritating to the skin. Depending on the size of the animal they can overdose on flea shampoos and have neurologic problems. Dawn Dish soap takes care of fleas better than any marketed flea shampoo and it’s so much safer.