Fleas in the Winter?

As I’m writing this newsletter there is a fresh blanket of snow on the ground and it is 23° outside. Even with the cold and snow, I have seen five dogs and two cats with fleas during today’s appointments. The question I get asked most often is “why are fleas still alive in the winter?”

The answer lies in understanding the adult flea life cycle. An adult flea can lay up to 50 eggs per day for more than 100 days after biting your pet. That means a small number of fleas on a dog can lead to 160,000 eggs being laid in two months! The flea eggs hatch in one to six days and become larvae. Then they go into the pupal stage in as little as five days and become adult fleas one to two weeks later. But, pupae can stay in this stage for up to four weeks and delay becoming adult fleas for that long. Depending on temperature and humidity, a flea egg can become a flea in as little as 14 days or as long as one year!

It is important to remember that even as temperatures reach freezing outside your home, it is warm enough inside to sustain the flea life cycle throughout the year. That’s why we recommend using flea prevention year round. This helps control the flea population. It is difficult to kill all the flea eggs because 84% of the flea’s life cycle happens at the base of the carpet where flea egg have been deposited, and most household pesticides can not penetrate through the carpet. 

Fleas not only cause annoying itching and discomfort for your pets but they can also bite people.  Fleas can infest dogs with tapeworms and may carry other diseases.  Also, dogs and cats can be allergic to flea bites. This occurs when the flea bites and injects its salvia into the skin of your pet. Up to 55% of dogs that have fleas also have a flea allergy in the US. It is important to remember that fleas may not be seen on the dog because he/she is repeatedly scratching and rubbing them off.

Also, fleas do not have to be present or seen on the dog or cat for the veterinarian to diagnose a pet with flea allergy dermatitis (allergy to flea bites). Even when a dog is not allergic to fleas, he/she may be itching from flea bites. Any dog that has fleas may introduce flea eggs into the environment – so be careful when you have pet play dates! If a dog has been diagnosed with seasonal or food allergies or atopy (generalized allergies), he/she should be on flea control medication all year round to decrease the allergen load and lessen the itching that he/she experiences.

If your animal has been diagnosed with fleas, he/she should be on flea treatment for at least six months so that the environment has time to be cleared of all eggs and pupa. After the infestation is eliminated, it is important to continue the flea prevention so that fleas do not come back. We do not recommend using over the counter flea medication because they have not been found to be effective and have a low level of safety.

For dogs and cats, you should consult with Feeder Creek so we can customize a flea program that’s best for you pets.   It is important to remember that just because its winter doesn’t mean fleas aren’t here – keep your pets on flea prevention and control year round to give them the most protection!          

  By Jonathan A. Yardley, DVM