Why Do We Have Fleas Indoors in the Winter?

By Chris Williams on February 10, 2016.

This is the first time this has happened. We have a dog and a cat so we often have flea problems in warm weather. Both animals are treated by our veterinarian when needed. But it’s winter here in New Hampshire and we are having a flea problem in our house. Our pets were treated in the fall but we’re still getting bitten by fleas!

C. C., Epsom, NH

You’ve probably just been lucky that this hasn’t happened before since you don’t mention having had any flea treatment of your home itself. We always tell people that flea control is a two-part (at least) process. Treating your pets kills the fleas on the animals but has no effect on immature fleas that continue to develop off of the animal inside your home (see Fleas Still a Problem).

To really get rid of fleas, you have to vacuum and then have a professional exterminator treat your home, concentrating on areas where your pets sleep and spend their time because that is where you find flea eggs and larvae. Then follow up by thoroughly washing pet bedding (see How to Get Rid of Fleas in Your Pet’s Bedding).

Flea Biology 101

To understand how to effectively get rid of fleas you need to know a bit about how they develop:

  • Adult fleas spend all of their time on the pet (when available) clinging to hairs and feeding on its blood.
  • Female fleas lay eggs that fall off of the animal and end up in various places, but most are found where the pet sleeps or rests.
  • The eggs hatch into white, wormlike larvae that develop in the same pet resting areas where they feed on feces (which is mostly dried blood) that drops from the adult fleas.
  • When the larvae are fully-grown, they pupate in a small cocoon and later emerge as hungry adult fleas. These new adults will jump onto a passing pet, or sometimes a person, and the cycle continues.

Your Pets Can Pick Up Fleas Outdoors

Pets that go outside can pick up fleas outdoors although the outdoor flea population dies or becomes inactive in winter (See Fleas Can Reinfest Your Home From Outside). This year’s warmer fall and early winter temperatures probably also contributed to your flea problem. Fleas from your pets and from other animals may have remained active outside later than usual. You don’t say exactly when your pets were last treated so they may have been re-infested by fleas after that treatment wore off.

To Get Rid of Fleas, Have Your Home Treated By a Pro

You may be getting bitten by fleas either because your pets are still protected by their on-animal treatment and fleas are desperate for a blood meal, or because there are so many fleas present that they are looking for other animals to feed on.

You need to give Colonial Pest a call and have one of our flea specialists inspect and treat your home to kill the flea eggs and any developing larvae. At the same time, you should contact your veterinarian to see if your animals need to be retreated for fleas. Remember, you can’t have one without the other if you want to be flea-free!



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