Fleas are the most important external parasite of dogs and cats world-wide. In addition to just being a nuisance, fleas are responsible for flea allergy dermatitis (FAD) in dogs and cats, which is estimated to account for over 50% of all the dermatological cases reported to veterinarians.

Repeated flea bites cause discomfort to pets and humans. But in heavy infestations repeated bloodsucking can also lead to iron deficiency anemia, especially in young animals.

flea_2Fleas are also vectors of several diseases and parasites. For example Rickettsia typhi, the organism responsible for murine typhus in many small animals and humans. Worms, especially Dipylidium caninum, also known as tapeworm in dogs and cats, can be transmitted by fleas.

Symptoms of fleas include:

  • Scratching and general discomfort of the animal
  • You may also see grains resembling salt and pepper in places where your pet sleeps or rests. These are eggs and flea dirt that indicate that fleas are reproducing.
  • If you should notice any of these signs, contact your veterinarian.

Checking for Fleas

flea_dirtThe best way to check whether your animal has been in recent contact with fleas is to check for the presence of flea feces. To do this you will need a piece of white paper and some moistened cotton.

First sit your cat or dog on the piece of white paper, and rub it’s back vigorously for a minute or so. As you rub, any flea feces will fall onto the paper. Then pick up the piece of paper, remove any hair, and transfer the ‘rubbings’ onto the damp cotton. Leave it stand for a minute.

Flea feces are made up of dried blood from the host they have bitten. When dry, they are dark black flecks that can be easily confused with dirt or dead skin. Once transferred onto the moist cotton, they will dissolve and turn a lighter shade of red. So, if you can now see red spots on the cotton, your pet has been in recent contact with fleas. Treatment is required.

Why fleas are a problem

  • Flea saliva is one of the most allergenic substances known to man. Some 10% of cats and dogs will suffer from Flea Allergic Dermatitis, a skin condition that causes major irritation and hair loss.
  • Fleas are the way in which a common species of tapeworm is carried from one animal to another, and occasionally to humans. If you kill the fleas, your pets cannot get tapeworms.
  • When fleas bite, they consume a small amount of the host’s blood. That won’t usually cause a problem for healthy adult cats and dogs. But a heavy infestation of fleas can remove enough blood to kill a small puppy or kitten.
  • The most common species of flea on both cats and dogs is the Cat Flea. Cat Fleas will not live on humans, but they certainly will bite us.

The flea life cycle

flea_4A female flea can lay 30-40 eggs in just one day. When your pet gets fleas, eggs fall off wherever they go in your house. In approximately three days, these eggs hatch into worm-like larvae that move away from light and downwards, usually deep in carpet pile.

After 7-18 days they spin a protective cocoon around themselves and develop into adults. Inside the cocoon they are almost impervious to insecticides.

It takes between 5-14 days for fleas to develop inside the cocoon, after which they are triggered to hatch in response to vibration or the carbon dioxide exhaled by a passing host. But in the absence of a trigger, they can survive inside the cocoon for up to nine months.




Important Flea Facts

  • For one animal to catch fleas from another requires that the two animals are in prolonged, stationary contact. Your pet is therefore very unlikely to catch fleas from casual contact with an infested animal, like in a park.
  • If you find fleas on your pet, the most likely reason is that it has visited another household with fleas, or a visiting cat or dog has brought them into your home.
  • If you have more than one cat or dog living in the same household, they must all be treated against fleas at the same time. Just one untreated pet can act as a ‘safe haven’ for fleas, thereby triggering a new infestation, or preventing you from clearing an existing one.

Flea Control and Prevention

flea_5A successful flea control program involves treating the environment. Adult fleas spend most of their time on an animal, but the eggs, larvae, and pupae are found in large numbers in the environment in carpet, rugs, bedding, furniture, and grass. To control the flea population, you need to remove fleas from the indoor environment, the outdoor environment, and your pet.

Flea control is complicated by the fact that there are many wild animals which serve as reservoirs for flea populations. Cat fleas can infest over 50 species of animals worldwide. In the U.S., coyotes, foxes, raccoons, rodents, skunks, opossums, and ferrets can be hosts for fleas.

Getting rid of fleas is difficult. Pupae that have been lying dormant hatch. The pupal stage of the flea can lie dormant for months, is protected by a cocoon, and is resistant to most insecticides. It is important to keep treating the environment and your pet until all of these pupal stages have hatched.

Flea control products include adulticides, chemicals that can kill immature forms, insect growth regulators/development inhibitors and combinations of the above. The products you choose depend on:

  • The extent of the flea infestation
  • The species, breed, health status, and age of your pet
  • The environment
  • The presence of other pets
  • Special family needs (i.e. infants in the house)

Your veterinarian can help you make the best choice of flea products for your pet.

Cleaning Lady IllustrationIndoor flea control involves removing all stages of fleas by vacuuming thoroughly (especially where your pet sleeps). When you have finished vacuuming, enclose your vacuum bag in a plastic bag and discard it immediately. Vacuuming needs to be done daily in high traffic areas and weekly in less used areas of the house. Vacuuming can remove as much as 50 % of the flea eggs. Wash your pets’ bedding weekly. Treat your car, pet carriers, garage, basement, or in any area your pet spends time.

You can use an adulticide to kill the remaining adult fleas. These can come in carpet powders, foggers, or sprays. Foggers are good for large open areas. Surface sprays can reach areas like baseboards, moldings, under furniture, and other areas foggers cannot reach. Children, all animals, and persons with asthma should not be present when these chemicals are used. Severe infestations may require the assistance of a professional exterminator.

Flea control in the outdoor environment usually involves treating the yard and kennel areas where fleas are most likely to be found. Fleas like moist, warm, shady areas with plenty of organic debris. They will also tend to congregate where pets spend more of their outdoor time. Concentrate on controlling flea populations in areas like patios, porches, and dog houses.

Remove organic debris like leaves, straw, and grass clippings to disturb flea habitats and allow any flea and tick products you use outdoors to penetrate. When possible use environmentally safe sprays containing fenvalerate. You may need to treat the yard every 10-30 days depending on the product. Do not spray where runoff could go into streams, lakes, or rivers.

There are multiple ways to apply flea and tick control products to your pet:

Once a month topical flea products like Advantage and Frontline Plus are applied to a small area on the back of the pet between the shoulder blades and are probably the easiest, most efficient, and longest lasting flea product. Many are water resistant or water proof, after 48 hours. Flea sprays and powders are messy, can be toxic to your pet or your family, and are much less effective than the topical flea products. Flea dips have minimal residual activity and can be harmful to your pet’s eyes and if inhaled by humans. Flea shampoos get rid of existing fleas, but have minimal residual activity. Shampoos can also be harmful to your pet’s eyes and ears. Flea collars are not a good choice since they lose effectiveness when they get wet, and can cause an irritation or allergic reaction. Oral or injectable medications like Trifexis or Program contain insect development inhibitors. The tablet for dogs is given once a month and the injectable form for cats is given every 6 months. These products do not kill fleas, but sterilize them. By far the best flea control is flea prevention.