CVMA-ACMV

Fleas Continue to be a Problem Despite Advances in Prevention

October 23, 2012

Fleas have literally been around for millions of years and have tormented man and his pets ever since man first started walking upright and keeping pets. Fleas are ideally suited to their task and are designed to survive against all odds, and it is this survivability that makes them such formidable antagonists.

Fleas are small (1-2 mm), brown, wingless insects, equipped with powerful hind legs that allow them to jump onto pets. Their flattened bodies allow them to race through a hair coat, and their tough bodies are able to withstand the vigorous scratching that pets do when they are infested with fleas. The most common flea species on both dogs and cats is the cat flea (Ctenocephalides felis). The dog flea (Ctenocephalides canis) is found on pets only occasionally.

Fleas bite both pets and people (although they prefer pets) and feed on their blood in order to survive and reproduce. These bites cause small red swellings that are very itchy, leading to severe scratching and self-trauma. Severe infestations can cause anaemia, especially in young puppies and kittens. Fleas are also involved in the spread of tapeworms and, in cats, a blood parasite called haemobartonella.

Female fleas can lay from 10-40 eggs per day. During the lifetime of the average female flea, she may lay up to 600 or more eggs, which eventually fall off the pet and end up in the surroundings. Eggs hatch in about 2-12 days and larvae emerge. Larvae then spin cocoons and become pupae within 1-2 weeks under average environmental conditions. The pupae are extremely tough and resistant to adverse conditions, pesticides and insecticides and can even survive freezing. This pupal stage usually lasts for about 8-9 days, but can last for up to one year.

Contrary to what was believed in the past, adult fleas live permanently on the host animal and do not jump off after feeding it is estimated that only about 5 per cent of fleas in the home are adult fleas. By contrast, flea eggs account for about 50 per cent of the total infestation problem while larvae account for 35 per cent and 10 per cent are in the pupal stage. These stages tend to occur in carpeting, furniture, and in cracks and crevices.

When a pupa "detects" vibration (e.g., a person walking into a room) or increased carbon dioxide concentrations (e.g., a person or pet exhaling), the adult flea emerges from the cocoon. Even a very small flea population can cause a heavy flea infestation. Given average environmental conditions, the entire flea lifecycle usually takes about three to four weeks. Adult fleas die or are knocked off the pet by licking, scratching or grooming in seven to 10 days.

With an understanding of the flea life cycle, owners can appreciate the importance of flea control that is directed not only at their pets but the environment as well. If there is to be any hope of success in controlling flea infestations, prevention (and treatment) must include both pet and household. Because of the numerous variety of flea control products available on the market, your veterinarian is the only health care professional qualified to advise you on which flea control program is ideal for your situation and your pet.