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How To Control Fleas

Flea Life Cycle

Fleas go through four main stages in their life cycle: Egg, larva, pupa and adult. Their life cycle can range from a few weeks to over one year, depending on environmental conditions. The adult flea can lay thirty to forty eggs per day on its host. The adult flea spends its entire life on the host but their eggs fall off the host and onto the ground, carpet, bedding or floors. The eggs will hatch in as little as two days to a few weeks. The eggs hatch into small, caterpillar-type larvae that feed on organic matter or the adult fleas' droppings which contain blood from the adult fleas' blood meal. In one to three weeks, the larvae spin a silken cocoon and they move into the pupal stage. The adult flea can emerge from the cocoon from one week to one year depending on the environmental conditions. Temperatures above 70 degrees and high humidity can make the adult fleas emerge faster. Vibrations from passing humans or other animals can also speed up the process.

Flea Allergy Dermatitis

A flea's main food is the blood it ingests from the host it lives on. When they bite their host to feed, their saliva can be very irritating and can cause a very intense itching sensation. Some animals are allergic to the flea's saliva and they can develop and allergic reaction called Flea Allergy Dermatitis or FADS. These animals will often chew their skin until it is raw and bleeding.


When dogs are infested with fleas, they usually chew on their back, just above their tail, on their sides, abdomen, and on their rear legs. Cats with fleas will groom excessively and they will have scabs and hair loss down their spine from their shoulders to their tail.

How to Diagnose Flea Problems

If you suspect that your pet has fleas but you don't see any, you need to look for the flea droppings which look like small, black specks of pepper. The adult flea ingests blood from its host. Their droppings contain a lot of blood, which contains protein that nourishes the larvae that eat the droppings. The best place to look for the droppings is just above the tail on the dog's or cat's back. If you find a speck of suspected flea dropping and place it on a piece of white paper, it will dissolve and turn a rusty brown to red color if you moisten it with a drop of water, giving proof of a flea infestation.

How to Treat for Fleas

If your pet has fleas, you have to treat every animal in the house and all outdoor pets at the same time. Shampoos and dips will only kill fleas for a few days. Shampooing your pet with any shampoo will usually wash off the flea eggs and droppings. The top-line topical flea products will usually kill fleas for three to four weeks. It is important to keep in mind it may take anywhere from three to twenty-four hours for topical products to kill adult fleas. Also, as newly-hatched adult fleas emerge in the house and yard, they will jump onto your pet. When you see these newly-emerged fleas on your pet you may assume the flea product is not working, however, it will eventually kill these new fleas. You will continue finding new, adult fleas on your pet until all the fleas in the environment are eventually killed. There are oral products sold by veterinarians that can help control fleas if you prefer not to use topical products.

Prevention Is Best

If your pets do not have fleas but they have exposure to them, it's best to prevent an infestation rather than treat one by using a good topical or oral product during the flea season. There are several products on the market, both topical and oral that combine heartworm and flea control in one application. We are more than happy to help you pick a product here at Milford Animal Hospital. Any questions or concerns please ask us. 

House and Yard Treatments

Spraying your yard for fleas is usually a waste of money. Newly-hatched larvae need a warm, moist place out of the sunlight to survive, so most flea eggs that drop off in your yard will be eaten by other insects or will not survive once hatched. If you want to spray effectively outdoors, you should spray under bushes or decks where it is warm, moist and dark. Spraying inside your home with a product that kills adult fleas and keeps the eggs from hatching is very beneficial. Be sure to treat all pets before treating the house.

Treatment Failures

Most treatment failures are due to poor owner compliance, not treating monthly and not treating every pet in the house or outdoors. The other reason for failure is due to flea eggs that drop off from stray or neighborhood cats, dogs, raccoons and other mammals that frequent your yard.

Which Products Are Best?

Some topical flea products work better that others so I recommend you consult your veterinarian before purchasing any product. If you purchase products from your veterinarian, they may cost a little more but your veterinarian will always be there to advise you and help eliminate fleas from your pet's environment, making you and your pets very happy.

When to Treat

In the South, pets should be treated with flea preventive year-round, but in the Midwest, preventive applied from May through October or November is usually adequate. I only recommend treating for fleas during the winter if you have a serious flea infestation the in fall.

Don't get discouraged. If treated properly, all flea infestations can be controlled.


© Gary L. Clemons DVM

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