Fleas: A common problem from coast to coast

A pet in his home itches his neck as his owner vacuums nearby

It helps to know your enemy

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

Comfortis™ kills fleas before they can lay eggs, breaking the flea life cycle

A flea newly emerged from its cocoon (pupa) can begin feeding within seconds and laying eggs within 24 hours after taking its first blood meal. Comfortis™ begins killing fleas in 30 minutes, before they lay eggs.

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 its first blood meal[6].

Female fleas can produce 40 to 50 eggs per day, up to 2,000 in their lifetime[1]. 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”)[5].

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 Pupa 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 days[8], 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 dioxide[6].

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 wildlife.

The most common adverse reaction recorded during clinical trials was vomiting. Other adverse reactions were decreased appetite, lethargy, redness of the skin, hyperactivity and excessive salivation. Click here for important safety information and full product label (PDF).

[1] M.W. Dryden, Integrated Flea Control: Flea Control for the 21st Century; presented at the North American Veterinary Conference, January 2001

[5] Bowman, Dwight D. Georgi’s Parasitology for Veterinarians, pgs 38-43

[6] 2005 Flea Guidelines, Flea control for dogs and cats, Advanstar Veterinary Healthcare Communications, sponsored by an educational grant from Merial

[8] Michael W. Dryden and Michael K. Rust. 1994. The cat flea: biology, ecology and control. Veterinary Parasitology 52:1-19

Flea Life Cycle Diagram