Even during the coldest season of the year, fleas can be a problem for our dogs and cats. In fact, stopping flea treatments in cool months has been attributed to the infestation of pets.1,2,3 So how do fleas defy frigid temperatures and how are you best able to protect your pets? Let’s take a look...
Thankfully no flea (whether it’s in the egg, larvae, pupae, or adult part of its cycle) can survive in near- freezing temperatures for extended periods.6,7 However, fleas are crafty creatures and will seek warm- bodied hosts (e.g., dogs, cats, raccoons, opossums) or warmed shelters (e.g., sheds, garages, your home) in order to survive all year long.3 Immature fleas can even develop in freeze-protected dens of wild animals.
At least not in the traditional sense. Adult fleas can enter an inactive state within their cocoon for up to 5 months9, 10, 11, 5 but temperatures below 37.4°F (3°C) kill these pre-emerged fleas.1 This is why adult fleas seek warm or insulated areas to lay their eggs, from which the flea larvae emerge during spring when conditions are more ideal.
The adult female flea typically lives for several weeks on a host (such as your pet). During this time, she will suck the host’s blood two to three times and lay twenty to thirty eggs each day. She may lay several hundred eggs over her life span. These eggs fall off of the host into the yard, bedding, carpet, and wherever else the animal spends time.
Flea eggs then proceed to develop where they have landed. Since they are about 1/12 the size of the adult, they can even develop nearly anywhere – e.g., small cracks in the floor or between crevices in carpeting. The egg then hatches into larvae. These tiny worm-like larvae live among the carpet fibers, in cracks of the floor, and outside in the environment. They feed on organic matter, skin scales, and even the blood-rich adult flea feces.
The flea larvae grow, molt twice and then form a cocoon and pupate, waiting for the right time to hatch into an adult. These pupae are very resilient and are protected by their cocoon. They can survive quite a long time, waiting until environmental conditions and host availability are just right. Then they emerge from their cocoons when they detect heat, vibrations and exhaled carbon dioxide, all of which indicate that a host is nearby. The newly emerged adult flea can jump onto a nearby host immediately.
The best way to kill fleas and prevent infestations is to combat them year-round. That said, winter may actually be the perfect season for you to take on the fight since it will often be when fleas are least active and fewer in numbers.
Start by regularly vacuuming the areas where your pet spends time and regularly washing pet bedding with hot water. If your area is experiencing a mild winter or you live in an area where plants, trees, grasses, and shrubs abound year-round, practice anti-pest landscaping. This includes keeping your yard trimmed and orderly as well as cleaning up piles of debris and leaves that may be littering the ground. Fleas love to congregate in places where they are protected from bright sunlight and that have slightly higher humidity.
Most importantly, consult your veterinarian about using flea preventatives year-round. Having your pet skip even one or two months of a flea preventative regimen may inadvertently cause a flea infestation to begin in your home or on your pet. There are many different flea preventatives to choose from, including spot-ons, oral medications and flea collars. Each preventative has its own way of eliminating fleas and duration of effectiveness. Some medications are even effective at protecting pets from fleas for up 12 weeks. Your veterinarian can make suggestions based on your preferences and your pet’s unique situation.