The Flea Lifecycle: Know Your Enemy

Fleas are one of the most common parasites which afflict our pets. They feed on the blood of their host and hence cause the pet to become anemic. The reduction in whole body blood supply can lead to weakness, lethargy and even death. Moreover, fleas can transmit tapeworms to your pet as well as infectious diseases including typhus, bubonic plague both of which are transmissible to people.

Fleas can make your dog itch and cause considerable discomfort, often leading to severe skin infections, bad odor and bleeding sores. Because fleas are so tiny, you might not even see them. But an unseen flea can begin feeding on your dog within seconds. And within 24 hours of its first blood meal, a flea can begin laying eggs. Egg production can reach a rate of 40–50 per day, resulting in an infestation. That’s why it’s critical to kill fleas quickly, before they can lay eggs.

To protect your pet and home from fleas, it helps to understand the flea lifecycle.

The Egg Stage:

Adult fleas can begin feeding within seconds of finding a host. They must feed to begin reproduction, and female fleas will begin producing eggs within 24 to 48 hours of taking their first blood meal2.

Female fleas can produce 40 to 50 eggs per day, up to 2,000 in their lifetime1. The eggs readily fall off the hair into the environment, so you can think of your dog as a flea-egg “salt shaker.” Wherever the pet spends the most time is usually where the heaviest flea infestations are found.

The Larval Stage:

Larvae hatch from eggs in one to six days given appropriate environmental conditions (a relative humidity between 50 percent and 92 percent). Their principal food is adult flea feces (“flea dirt”).

Flea larvae are small, thin and white, measuring 1 to 2 millimeters in length (about the thickness of a dime). Indoors, flea larvae tend to live deep in carpeting or under furniture. Outside, they develop best in shaded areas or under leaves or similar yard debris. Any area of a yard where a pet seeks shelter from the heat or cold is potentially a great environment for fleas.

The Pupal Stage:

A mature larva transforms into a pupa inside a silk cocoon. Under most household conditions, the adult flea will emerge in three to five weeks. However, a fully developed flea can remain inside the cocoon for up to 350 days4, a reproductive strategy that enhances the flea’s chance of survival. This helps to explain how a flea infestation can seemingly “explode” out of nowhere, even inside your home.

The Adult Stage:

Adults emerging from cocoons can begin feeding immediately if a host is present. They are attracted by body heat, movement and exhaled carbon dioxide2.

The flea feeds through a tiny, slender mouth part called the proboscis. Before feeding, it pumps saliva, which contains an anticoagulant, onto the skin. This prevents the blood from clotting, and the protein it contains can cause a severe allergic reaction in the host (flea allergy dermatitis).

Adult fleas can survive throughout the winter on pets as well as on wildlife.

Flea Control

Because fleas lay so many eggs, if your house is infested, you may need to spray the rugs and bedding with a product, which can kill both the adults and eggs. Our veterinarians recommend Knock-Out spray and foggers for this purpose.

On the pet, you can use a topical treatment, such as Frontline Plus, which is administered on the skin above the neck once a month to kill the fleas. This product is water proof and will not wash or bath off once it is applied. It also protects the pet from intestinal parasites (roundworms and hookworms) and it will kill ticks as well.

If you prefer to administer a pill once a month instead of apply a topical, Trifexis™ (spinosad + milbemycin oxime) is a great alternative. It kills fleas before they lay eggs. A single pill taken once a month will keep your pet free of fleas. In addition, it will prevent heartworm infestation and kill the intestinal parasites; whipworms, roundworms and hookworms.