Fleas are parasites of most mammals and birds, particularly irritating because of their frequent bites. The usual flea to infest dogs is the cat flea, Ctenocephaldes felis, with the dog flea, Ctenocephaldes canis being less common. They will quickly and easily jump from dog to man to cat or so forth, not being particular from whence they feed. They prefer to live below 5000 feet elevation, and thrive in warm, moist climates.

Fleas live by sucking blood from their hosts. Eggs are laid on the host or in carpet, bedding materials and the yard. They hatch into maggot-like larvae, which feed on flea dirt, which is the fecal material of live fleas, made up primarily of blood, and other debris in the area. The female flea can lay hundreds of eggs in her lifetime, which is why fleas seem to multiply before your eyes. The flea larvae form a cocoon, pupate, and then hatch into adults. This whole cycle takes as little as 3 weeks, but can last almost 2 years; it will proceed fastest in the warm and humid summer months.

The bite of the flea alone is quite itchy, but in some dogs, a severe, intense allergic reaction to flea saliva, known as Flea Allergic Dermatitis can occur. These dogs have hair loss, extreme itching, and secondary infections of the skin. Fleas may be identified by seeing 1-2mm black/brown specks racing (they move very fast) across the back, groin and hindleg areas of the dog. Tiny sand-sized black specks may be present in the fur, called flea dirt, which if wetted, will turn red, as this is digested blood-droppings of the flea. Tiny white specks may also be seen on the fur, these being the flea eggs.


At any given time, only 1% of the flea population exists in the adult stage; the other 99% are eggs, larvae and pupae just waiting to become adults and infest your dog. Understanding this fact is essential to winning the war against fleas; simply spraying or dipping the dog will seldom do more than destroy a tiny fraction of your local flea army. There is no one-plan-fits-all strategy, but in short, killing and repelling fleas on the dog, as well as destroying and removing the eggs and larvae from the house and yard are essential parts of any strategy.

It is best to work with your veterinarian to select safe and effective products. There are hundreds if not thousands of products sold today, many that are unproven and unsafe. Your veterinarian will generally have the latest improvements and safest agents available. Avoid untrained pet store personnel who have little training in chemistry and parasite control. Most are simply trying to sell you a product, not treat your pet in the best possible manner.

TOPICAL REPELLANTS such as Frontlinetm and Advantagetm, are applied to the skin of the dog or cat where they spread out and over the entire skin area. These provide a sort of total body flea collar and are very effective in killing and repelling fleas. These agents have minimal toxicity for most pets: side effects are very rare. This is considered the "state of the art" in flea and tick control today. Avoid "knock off" products. We have seen poor performance and some severe toxic reactions from many off-brand chemicals sold in pet and retail stores.

DIPS provide quick and effective flea kill and can usually be mixed from a concentrate and poured or sponged onto your dog. You must dip about every two weeks as the dip will weaken in about that time. Do not rinse off the dip to provide residual anti-flea activity. We have had great success with Paramite dip.

TOPICAL SPRAYS work well to quickly kill fleas, and a few will provide residual protection or prevent eggs from hatching out later. Sprays can be used between dipping, and in conjunction with topical and systemic medications. Alcohol-based sprays work best, but some people and dogs may be bothered by the fumes, so less effective water-based treatments are also available. Please ask as to what sprays are currently available.

POWDERS are usually safe and inexpensive, but are slow to kill, and you must powder your dog every few days to maintain their effectiveness. Powders also do little more than kill adult fleas only.

SHAMPOOS also kill adult fleas, and assist in cleaning eggs and dirt from the coat, but have minimal residual activity or effectiveness against pre-adult fleas. Using shampoo then dipping or using a spray is the best strategy.

FLEA COLLARS, if they are high quality, can help kill and repel fleas, but have been pretty well replaced by topical products mentioned above. Poor quality collars can be toxic to you dog, and can irritate the skin on the neck of your pet, so avoid the grocery store brands.

SYSTEMIC AGENTS like Programtm, the trade name for the drug lufenuron, is an oral systemic which is completely non-toxic to the pet, and when ingested as the flea sucks blood, renders her eggs incapable of producing adult fleas. This does nothing to kill adult fleas and other products will still be needed. Programtm will, however, cut the flea problem down at its very roots and is highly recommended. It is considered safe in conjunction with sprays, and other topical agents.

FOGGERS and SPRAYS for the house and yard are useful in controlling the balance of your flea population. Newer foggers have time-release agents providing kill for weeks after application. Many contain growth regulators to inhibit the hatching of eggs already in the environment. Foggers also apply their chemicals EVERYWHERE which happens to be where the fleas live, so these can be very useful in getting a bad flea problem quickly under control. Many sprays work in similar fashion but are better suited for direct application to baseboards and bedding areas where the heaviest infestations occur.

Vacuuming the carpets, or better, using a carpet cleaning machine before spraying or fogging works well to remove eggs, larvae and pupae, as well as the dirt on which the larvae feed. Be certain to dispose of vacuum bags far from the house as live fleas can crawl out and find their way back home.

Spaying the yard; grass, fences, patios and dirt areas with a yard spray made for fleas is also important to get flea problems under control. Spraying may be needed every 7-10 days in warmer weather, and you can do it yourself or hire professional exterminators to do the job for you. Be careful to keep your dogs away from freshly sprayed areas until they are dry.



2007 James W. Day D.V.M., P.C.