Fleas are wingless, external parasitic insects which drink the blood of their host. They are small (under 1/8-inch) and dark-colored, with long legs and tube-like mouth parts. Their bodies are hard and covered with backward facing spines and hairs, which allows them to move easily on their host. Fleas can jump 7 inches straight up into the air and horizontally up to 13 inches. Fleas are hard to kill with pressure or scratching--they must be crushed between fingernails, drowned, or poisoned.
Fleas go through four life cycles; egg, larva, pupa, and adult. Flea eggs are tiny, white, and oval-shaped. The adult female feeds, then lays the eggs in batches of 20. Because the eggs are laid so close to feeding, they are usually laid on the host itself â€“ so eggs may be found where the host sleeps. Eggs take between two days and two weeks to hatch into larvae. Larvae are eyeless and feed on the feces of adult fleas and other organic matter. After several months, the larva weaves a silken cocoon into which it disappears to develop into an adult. The adult emerges in five days to two weeks, and must have blood within one week or they will die. Adult fleas which are completely developed can survive up to a year without feeding, but cannot reproduce.
Flea bites cause raised welts with a puncture in the center. They will feed on any mammal, including dogs, cats, birds, mice, humans, and squirrels. Fleas are capable of transmitting several diseases, and causing several medical problems, including flea allergy dermatitis, skin infections, anemia, tapeworms, bubonic plague, and more.
Testing and Detection
Fleas are fairly easy to detect on pets. There will be small brownish specks attached to the fur - this is undigested blood. Wet a paper towel and touch it to the spots. If it turns red, you'll know it's flea dirt. In addition to the flea "dirt" your dog will show signs of irritation - he will scratch or bite at himself, and you may see raised bites from the fleas. Extensive infestations or dogs with flea allergy dermatitis may have bald spots with red skin. Fleas are visible to the human eye, and you may see them crawling or jumping on your pet or his bedding.
Flea allergy dermatitis (FAD) arises in dogs that are allergic to the saliva of the fleas. Irritation may develop immediately, or take up to 48 hours to arise from one bite. Dogs with FAD develop small red bumps along the outsides of the backs of their legs and on the base of their tail. They may also have thickened skin at the base of their tail. Flea allergy dermatitis is confirmed with a intradermal skin allergy test, or blood tests.
Treatment is not as simple as just treating the animal - in a flea infestation, there are other sources to consider: bedding, carpeting, any soft surfaces, and the owner's bed. Reducing humidity in the home to below 50% is one way to stop the growth cycle, since eggs require at least 50% humidity to survive. Lower temperatures (below 70° F) may stop the cycle as well. Vacuuming catches a large majority of the present fleas, but the bag must be disposed of immediately outside the home. All pet and human bedding should be washed in hot water and dried on high heat to kill adults, larvae, and eggs. All pets in the household should be treated to kill both adults and eggs. There are many non-chemical methods available for use, such as diatomaceous earth, rosemary spray, lavender oil, and cedar oil. There are several chemical treatments for flea infestations, but care should be taken, as some breeds are highly sensitive to the toxins used. The best method is to use a combination of several different natural methods. Note - most essential oils are toxic to cats, so avoid lavender oil and cedar oil if you have cats in your household.