Flea Control in Dogs


My dog always seems to have fleas. What can I do?

Successful flea control involves both eliminating fleas from your dog and controlling fleas in your environment. Dogs and cats share the same fleas, and fleas can travel from one animal to another. Thus, it is important that all pets in your home are on a flea preventive program.

Treating your pet for fleas has never been easier. With the many choices we have today, we can provide you with the safest and most effective flea preventive for your pet's needs. However, when it comes to environmental control, it is important to understand the flea life cycle.

What is the life cycle of the flea?

There are four stages to the flea life cycle, namely the egg, the larva, the pupa, and the adult. The most important source of fleas is newly emerged adult fleas from flea pupae in your house or yard. Adult fleas live, feed and mate on our pets; the female flea lays eggs that fall off into the environment where they hatch into larvae. The larvae eat organic debris (such as dead skin cells and feces from adult fleas) until they mature into pupae. The pupae are encased in a sticky cocoon, helping them to camouflage in the environment and making them difficult to eradicate. Adult fleas will not emerge from the pupae until they sense an animal nearby to feed on. Newly hatched adult fleas jump onto a host animal to complete their life cycle. Two days after eating a blood meal from the host, the female flea begins to lay eggs. Under ideal conditions, the flea can complete its entire life cycle in as little as two weeks; in adverse conditions, the fleas within the pupae remain dormant and can wait as long as a year to hatch, when conditions are more desirable. Homes with carpets and central heating provide ideal conditions for the year-round development of fleas. The highest numbers of flea eggs, larvae and pupae will be found in areas of the house where pets spend the most time, such as their beds and furniture. Even though fleas may be in your house, you probably won't see them. The eggs are tiny white specks the size of dust particles, while the larvae, which are somewhat larger, with dark heads and lighter bodies, migrate deep down in carpets, furniture or cracks in floors away from the light.

Apart from irritation, are fleas particularly harmful?

In pets who are allergic to fleas, even one or two bites can cause extreme itching, leading to self trauma and skin infections. Since they feed on blood, fleas can cause anemia (low red blood cells) in heavy infestations, especially in young or debilitated dogs. In addition, fleas can carry several diseases, including plague, and act as vectors (hosts) to spread one of the most common tapeworms of the dog and cat, Diplylidium caninum.

How do I prevent fleas on my dog?

Year-round use of effective monthly flea prevention is the best way to prevent fleas on your dog and avoid an infestation of your environment. We recommend the monthly oral chewable, Nexgard, for dogs.

How can I get rid of fleas on my dog?

SUCCESSFUL FLEA CONTROL INCLUDES TREATING BOTH PETS AND THE ENVIRONMENT

This can be a challenging task and requires a three-pronged approach. Fleas need to be eliminated from your 1) dog, 2) from any other cats and dogs in your household, and 3) from your home and yard (environment). Once your dog’s fleas are under control, continued prevention is essential, since you cannot control some outside sources of fleas such as other people's pets, wild animals, or other property outside yours.

What should I put on my dog?

Although many OTC flea shampoos, sprays, and powders will kill adult fleas on your dog at the time of application, they can have limited effectiveness because they only work for a few hours after application. Most have no residual effect, meaning your dog will be infected with new fleas from the environment by the next day. We have very effective products designed for monthly administration that are available by prescription – our veterinarians recommend Nexgard, a chewable tablet which effectively prevents both fleas and ticks for 30 days. Some topicals, such as Frontline, are also effective monthly preventions, but run the risk of being washed off in dogs who swim or are bathed regularly. Regardless of which product you choose, it is essential that these medications be given on the same day each month to be effective. Be sure to consult your veterinarian to choose the most effective and safe flea products for your home and pet.

What about the environment?

In cases where fleas have invaded your home or yard, environmental treatment is crucial in controlling the population. This is because the adult fleas which are killed by our preventive medications only constitute about 5% of the population. The remaining life stages are hidden in your carpet, furniture, bedding, and yard (see flea life cycle section). A number of different products are available which will kill the adult and larval stages of fleas and stop the flea life cycle, such as:

  • Adulticide sprays for use in the house
  • Sprays containing insect growth regulators (IGR's) for use in the house
  • Insecticides applied by professional pest control companies

Sprays for use in the house should be used in places where the flea eggs, larvae and pupae are likely to be. It is recommended that you treat the entire household first and then concentrate on the hot spots - your dog's favorite napping spots - such as soft furniture, beds, and carpets. Once they hatch from the egg, flea larvae move away from the light and burrow deep into carpets and into other nooks and crannies where it is difficult to reach. Be sure to move cushions, furniture and beds to spray underneath them. Other places larvae are likely to live include baseboards and the cracks and crevices between floor seams or boards. You will need to throw away the vacuum bag to prevent eggs and larvae from developing inside the vacuum cleaner.

Sprays for use in the house should be used in places where the flea eggs, larvae and pupae are likely to be. It is recommended that you treat the entire household first and then concentrate on the hot spots - your dog's favorite napping spots - such as soft furniture, beds, and carpets. Once they hatch from the egg, flea larvae move away from the light and burrow deep into carpets and into other nooks and crannies where it is difficult to reach. Be sure to move cushions, furniture and beds to spray underneath them. Other places larvae are likely to live include baseboards and the cracks and crevices between floor seams or boards. You will need to throw away the vacuum bag to prevent eggs and larvae from developing inside the vacuum cleaner.

Flea eggs and pupal cases are extremely tough and resistant to the effects of insecticides. To remove these stages, as well as eliminate dead fleas, your pet's bedding should be washed in hot water or replaced. Regular and thorough vacuuming of your carpets, floors and soft furnishings can remove a large number of flea eggs, larvae, and pupae. Sprinkling carpet with diatomaceous earth or borax powder can help improve the mechanical destruction of flea larva by the vacuum. Vacuuming prior to the application of a spray to the house is recommended because the vibrations will encourage newly developed fleas to emerge from pupae, which will then be killed by the insecticide. *Note that some environmental treatment products contain pyrethrins or permethrins, which are toxic to cats. Cats should be isolated prior to treatment of the house with these products, and the products should be allowed to dry for several hours before reintroducing the cats.

Are insecticides safe for my dog and my family?

Insecticides for flea control should be safe both for pet dogs, cats and humans provided the manufacturer's instructions are carefully followed. One should be particularly careful to avoid combining insecticides with similar modes of action. Always seek your veterinarian's advice if you are unsure about this and always tell your veterinarian about any flea control products you may be using other than those that he has prescribed.

Certain types of pets (e.g. birds, fish, amphibians, reptiles and invertebrates) may be particularly susceptible to some products. Do not use any flea control products in the room in which these pets are kept without first consulting your veterinarian for advice.

Despite treating my dog for fleas he still has them. Is there a "super flea"?

There is no evidence of fleas developing resistant to insecticides, especially the newer chewable flea preventions like Nexgard. Apparent failure of treatment almost always results from improper application of the preventive, inadequate treatment of the home or exposure to other infested pets or environments. Consider treating storage sheds cars and any outdoor sleeping spots. Bear in mind that your pet may be going into other people's houses or picking up new fleas outdoors. Most of these problems can be overcome by using an effective product with residual activity on the pet in addition to treating your home.

It is important to remember that due to the tough nature of the flea pupae, it can take 2-3 months to completely eliminate fleas from your environment. During this time you may continue to see occasional adult fleas on your pet - THIS DOES NOT MEAN OUR TREATMENT IS NOT WORKING! Stick with the plan, and with time the population can be eradicated. You may also see adult fleas if your cat goes outdoors or visits environments which you can’t control, your preventive product should kill them quickly, before they can establish a new infestation in your environment.

My dog doesn’t spend much time outside, and I’ve never seen fleas, why do I need flea prevention year-round?

Fleas are not just an “outside dog” problem. In fact, most stages of the flea life cycle prefer our comfortable, climate-controlled homes, and will reproduce exponentially given the chance. A single adult flea tracked in on a pet or on your own shoes after a walk can become thousands of fleas within just a few weeks. In the case of fleas, “an ounce of prevention is worth a pound of cure” – preventions such as Nexgard are very effective, and much less costly in terms of money, time, and frustration than trying to eliminate fleas once they have gotten into your home and pet.

While fleas can be an unappealing and frustrating problem, by understanding the flea life cycle and following our advice, you and your pet will be flea free in no time.

This client information sheet is based on material written by: Ernest Ward, DVM © Copyright 2009 Lifelearn Inc. Used and/or modified with permission under license.

For a downloadable PDF version of our Flea Control in Dogs Handout, click here