Quarterly Newsletter

Spring 2003

"The fleas are coming! The fleas are coming!" - Paul Rover

Springtime is flea time. While these parasitic pests can be a problem year-round, they do not like the colder temperatures, and may go dormant or die off during the winter months. Once the weather starts warming up again, the eggs and pupae that were left behind will start hatching and viola; a new infestation has begun.

THE FLEA

The flea in question is Ctenocephalides felis, the common cat flea, which is found on both cats and dogs. Fleas have a fairly typical insect lifestyle: egg to larva to pupae to adult.

Flea eggs are ovoid in shape, whitish in color and about 0.5mm (1/32in) in length. They are fairly hard to see with the naked eye. Eggs are laid on the pet by the female flea after a blood meal, and quickly fall off into the environment. Depending upon the temperature and humidity, flea eggs can hatch within 14 to 28 days. With the exception of the adult flea, all flea life-stages favor a warm, humid environment.

Flea larvae are 2-5mm (1/8-1/4in) in length. They feed on organic debris (such as dead skin cells) and adult flea feces in the environment. They dislike the light and will move deep into carpet fibers or cracks and under furniture. Again, they prefer dark, warm, moist habitats. It is during this stage of life that fleas become infested with tapeworms, when a larva eats a tapeworm egg packet from an infested animal's stools.

The flea pupae are protected by a sticky, silk-like cocoon. This cocoon quickly becomes coated with debris and forms a kind of camouflage for the pupae. Within five to ten days, the pupae will develop into an adult flea. This pre-hatch adult can lie dormant within the cocoon for up to nine months, until hatching is stimulated by pressure, carbon dioxide or heat. During this time, they are very resistant to environmental insecticides. After adults emerge, they must obtain a blood meal within a few days to survive.

Adult fleas are attracted to light and will emerge to the surface in order to encounter a host. Two days after the first blood meal, female fleas begin egg production. They will live up to three weeks, laying approximately 40 eggs per day.

This means that one female flea can produce approximately 800 eggs during her lifetime. If approximately half of those are female (and assuming a 100% survival rate), the next generation of fleas could produce up to 320,000 new fleas. Depending upon environmental conditions, the entire flea life cycle can be completed in 14 to 28 days. Within a very short amount of time, you can have a very large amount of fleas to deal with.

WHAT HEALTH RISKS DO FLEAS POSE?

Fleas can pose several different health risks to household pets. In newborns, geriatric, and debilitated pets, we can see a condition called flea anemia. In these cases, the flea population is too large and they are in essence, overfeeding on one host and taxing that pet's resources.

In addition, fleas are vectors for certain infectious diseases, and they also serve as the intermediary host for the common tapeworm.

Perhaps the most common flea-related health problem we deal with is that of allergic reactions.

WHAT IS A FLEA ALLERGY?

An allergy is an overreaction of the immune system to foreign substances (allergens or antigens). Dogs and cats who suffer from flea allergy dermatitis (FAD) are actually sensitive to the saliva of the flea bite. An allergic reaction can result in biting, licking or chewing at the skin to relieve itching. This can in turn cause hair loss, scabbing and open sores, allowing a secondary bacterial infection to begin.

It can take as little as one flea bite in a sensitive pet to begin the cycle. While we can treat the symptoms and help to alleviate the pet's discomfort, it is also important to prevent the cycle from starting in the first place. Since the allergy is tied to the bite of the flea, we need to try to prevent the pet from coming in contact with adult fleas.