Keeping Fleas, Ticks and Mosquitoes Away … Even in the Winter

For those of us with pets, we look forward to winter as a time of respite from the bugs that torment us and our pets. We look forward to a break from the sprays and gels and powders and medicines … all the things we try on our pets and in our home to keep the blood suckers at bay. However — and we hope you are sitting down as you read this — winter does not necessarily spell the end of bug season. Consider the following …

The flea is a very persistent and resilient pest with a very complicated life cycle. It is even capable of surviving in outdoor temperatures as low as the upper 30s. As long as an adult flea can find a suitable host to feed from (such as wild animals or your pet), it can stay warm and healthy through the cold season. Their pupae remain settled in their cocoons until it is warm enough to come out — as long as they have been placed in a location where they are protected from freezing cold (for example, a garage, covered patio, or basement).

Flea pupae can remain dormant for over a year until the surroundings have reached ideal temperatures. Once conditions are ideal (either inside or outside), the pupae will complete their development and emerge from their cocoons en masse, resulting in a surge of activity both on and off your pets.

Generally speaking, 65-80 degrees Fahrenheit with 75-85 percent humidity is the ideal temperature range for growth and reproduction of fleas. All they need is a warm place in which to settle and lay their eggs. For the majority of pet owners who keep their homes at a consistently warm temperature throughout the winter season, this can mean that a flea population, once settled indoors, can remain active all year long.

For residents of the southern states of the U.S., where the winter season may only go as low as the 30s, fleas will often stay active throughout most or all of the winter season. Only sustained cold (less than 30 degrees) and low humidity levels will kill off outdoor eggs, larvae, and adult fleas.

The best time to fight fleas is during the winter, when there is the best chance that they will become less active and fewer in number. Regularly vacuuming the areas where your pet spends time and continuing regular flea treatments throughout the winter season are the best ways to combat them before the next flea season is in full swing.

Ticks are also capable of surviving winter temperatures when they are able to find a host to feed from or a warm location to hide in during the coldest weather months. Generally, adult ticks will still be a threat when temperatures hover around 45 degrees Fahrenheit.

For this reason, if your pet spends time outdoors in the winter, tick prevention is still a good idea. And since most medications are designed to thwart both fleas and ticks, it’s a good idea to use preventive medications through the year.


While most geographical areas do enjoy a seasonal respite from mosquitoes, the southern climes are still captive to their buzzing, blood-sucking schemes — even in the winter. Mosquitoes, of course, are carriers of the heartworm parasite, a life threatening nematode that can cause severe disease and even death. (Note: the heartworm actually takes up residence in the lungs. Read more about the symptoms of heartworm infection in dogs and cats.) Even in areas where residents do not have to worry about mosquitoes during the winter, their return in the spring and summer months can catch you off guard. It is best to be pre-prepared.

To safeguard your dogs and cats against heartworm infection, veterinarians suggest using heartworm prevention medication year-round. This is a much easier method of prevention, since you won’t have to remember when to star, or find yourself rushing to get the medication, and you won’t have to worry about having your pet tested for heartworms before beginning a new round of medication in the spring.

The final word on avoiding parasitic infestations of any kind is to use preventive techniques. Remember that while fleas, ticks and mosquitoes may seem to be merely nuisance pests, they are actually capable of causing severe health problems, from the above mentioned heartworm infection, to skin disorders and infections, to anemia. As the old axiom goes: It is better to be safe than sorry.