No pets, still seeing fleas emerge after 3 months and 3 exterminator treatments

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QuestionsCategory: Flea InfestationsNo pets, still seeing fleas emerge after 3 months and 3 exterminator treatments
Anonymous asked 1 year ago

Hi there,
Thank you for the great site – so informative and helpful. We moved into our new house 3 months ago and discovered a flea infestation left by the previous owners cat. We tried to solve the problem ourselves (vacuuming, salt, borax, shop bought flea spray etc) but after a few weeks got an exterminator in to spray the entire house. We have had him out 3 times (will be a fourth this week) as after some periods where they seem to be gone – bang – they emerge again. We think they are in the cracks in laminate floors and under the baseboards in the sitting room and hallway mainly (have found what appears to be remnants of a sticky white-ish empty pupae in the cracks). Could you give me some advice as to how to make the last remaining fleas emerge more quickly to hit the insecticide. We don’t have any pets and are ensuring not to be bitten ourselves – so we have to be near the end. We are considering ripping the baseboards off to get at the pupae. Note we really have only start vacuuming again this week as the exterminator told us not to previously.

Many thanks,

1 Answers
Adam Retzer FleaScience answered 1 year ago


Thank you for the compliments on the site!

You should definitely be towards the end of your problem. The fleas won’t be able to reproduce without any animals to feed on. They can’t reproduce on human blood. So, you’re seeing the last generation. That is, of course, assuming there are no animals in the home. Make sure no wild animals are living in the crawl space, attic, etc.

Enough time has passed where the eggs, larvae and pupae are completely gone. The only remaining stage left is the adults. The fleas you’re seeing are most likely adults emerging from their dormant-like stage. These ‘pre-emerge adults’ can remain inside their cocoons until they sense nearby heat and pressure, which indicates a host.

Unfortunately, insecticide treatments are least effective against pupae and pre-emerged adults. They are semi-resistant to treatments, plus they’re often protected in the environment beneath the carpet canopy (or within cracks of hardwood, etc). This is probably why you’re still seeing new fleas emerge after spraying and hiring an exterminator.

Here’s the good news: the pre-emerged adult stage can’t last beyond 5-6 months. Even without doing further decontamination, the problem will soon end on its own since you don’t have pets.

If you want to speed up the process, employ a regular vacuuming routine. Heat and pressure from the vacuuming will mimic a host and cause the cocooned fleas to emerge. The exterminator probably told you not to vacuum because it may remove some residual insecticide. However, vacuuming is best way to get the pre-emerged adults to emerge.

Ripping up the baseboards seems like an extreme measure. Especially considering the fleas should be extinct within your home soon. Though, I don’t know the full extent of your situation.

Wish you the best!


grettahalpin replied 1 year ago

Thanks very much for the advice Adam! I spoke with the pest control guy today before he did the spray and he said it is okay to hoover after a few days – just no mopping so hopefully that will wake any remaining fleas up and get them out into the insecticide. We don’t have a crawl space and have checked the attic; no signs there or anywhere else of wild animals so hopefully this is just the remnants of the fleas from the previous owners cat! In the last couple of weeks (after nearly 3 weeks of nothing) we are only seeing small bursts of 4 or 5 of them at a time (some dead, some alive) with a week or so in between each burst. We might see one or two dead or alive in between. We really can not wait to see a real end to this; its been very mentally, physically and emotional draining! I had no idea that something like this could happen and I grew up with cats and dogs in my parents home in the country. We never had any problems!Thanks again Adam; I’m feeling more confident now that this will actually come to an end.G.

Adam Retzer FleaScience replied 1 year ago

Glad I could help. I hope this problem ends very soon for you!

Gretta Halpin replied 1 year ago

Hi Adam,
I just had one more quick question – in lots of different sites on fleas I see them saying that that fleas can remain in their cocoons for up to 2 years! I know your estimate of 5-6 months is backed up by a lot of research. Would you be able to shed some light on why the pre-emerged fleas die after 5-6 months and don’t last longer as the other sites mention? We are still seeing some fleas emerge and I am hoping, based on your research, that by the end of April we should see no more!
Thanks very much,

Adam Retzer FleaScience replied 1 year ago


Pre-emerged fleas won’t persist for 2 years. All the literature I’ve read states that 5-6 months is the maximum length of time they can survive. Perhaps other species can last longer, but cat fleas (C. felis) can’t. And cat fleas are almost certainly the species in your home.

Within their cocoons, fleas enter into a quiescent state. This is almost like a dormancy, but not quite. There is no true dormancy or hibernation.

The reason why the fleas can’t survive 2 years is because they use up their metabolic reserves. In the quiescence, their metabolic activity is drastically slowed down, but it still continues. Eventually, they must emerge to feed or they’ll starve. This is evidenced by experiments showing that fleas from malnourished larvae can’t stay within their cocoons long at all.

Here’s the most comprehensive journal article on this topic:

Extended Longevity of the Pre-Emerged Adult Cat Flea and Factors Stimulating Emergence from the Pupal Cocoon

False information on websites results from unscrupulous internet marketing techniques from the recent past. And, of course, laziness with research. Web masters would write content which focused on keywords they knew people were searching for on Google. The content didn’t have to be accurate to get visitors. Once, the visitors were on the page, advertising commissions could be accrued.

Google has cracked down on this recently. However, a lot of this kind of misinformation still floats around the internet, on tons of different topics. It may take a while to disappear, as new webmasters often don’t research deep enough, and end up copying the incorrect information into their own new websites.

This is why I provide citations for all my content, because there’s a lot of incorrect information out there.