Fleas, A Scratchy Subject or Tiny Terrorist
by Tom Rood, Master Gardener
Cornell Cooperative Extension

Fleas have made themselves an important part of our lives and particularly so if we are pet owners. Commercially, their bite to get attention brings in around $1 billion in control efforts. Not bad for a tiny little creature, is it? Fleas belong to the order of Siphonaptera with 16 families world wide and seven families in North America alone. There are 325 species of North American fleas but over 2000 worldwide. The good news is that only four or five species are common enough for us to worry about. These are the cat flea, dog flea, northern rat flea, oriental rat flea and the rabbit flea. The cat flea is the more common flea and feeds on a very wide range of mammals. As one may expect, most fleas are opportunist, accepting whatever host happens to be available for feeding.

All adult fleas are blood-sucking parasites. Most feed on mammals, although less than ten percent can be found on birds. Fleas are most common on mammals, including humans, that have nests or beds they return to on a regular basis. This includes domestic carpets and upholstered furniture for pet owners. Nests and beds are great incubators for flea eggs. Mammals that move around without returning to the same resting place have far fewer fleas. Other indoor areas that will allow flea eggs to incubate are cracks and crevices, along baseboards, and under rug edges. Outdoors, sandy gravel soil, moist sand play boxes, crawl spaces under buildings, and shrubs are all places that provide a proper habitat for flea eggs to incubate.

Adult fleas are tiny, running from 1/16 to 1/8-inch long, are dark brown, wingless, difficult to crush because of their flat shell-like body, and have three pairs of legs. Their skinny flatness allows them to move easily between hairs or fur on an animal's body. Their hind legs are powerful, propelling them upwards to as much as seven inches and horizontally up to thirteen inches. If we humans had similar strength, we could leap over a 25 story building because we would be able to jump 250 feet straight up or 450 feet across the ground. That's 1-1/2 times the length of a football field. Although, on second thought, the splat on landing might be a hard on the next of kin.

Fleas pass through a life cycle that begins with an egg, passing through the larval-pupa stages to reach adulthood. Flea larvae are worm-like in shape and rarely live on a host. As mentioned above, they most commonly are found in nest or bedding where host animals sleep. They feed on organic debris including bits of hair, feathers, skin, and adult flea feces. After two molts, the fleas pupate in a tiny cocoon. Completion of the life cycle may take as little as two weeks or up to eight months depending on species and environmental conditions.

Adult females usually begin laying eggs after a blood meal. They can lay 15 to 20 eggs daily and up to 600 in a lifetime. Eggs are loosely laid on the host and many drop off; especially where the mammal sleeps. Egg incubation takes from three to ten days. Under ideal conditions, ten female adult fleas may be able to multiply to over a quarter million in as little as a month.

The normal life span for an adult flea may be two to three months but newly emerged adults can only survive for a week or so with out a blood meal. If however, the newly hatched adults remain inside the pupal cocoon, they can survive without a blood meal for several months and perhaps as long as a year or more. No wonder we are attacked when we return home after a vacation. With no host such as a dog or cat to feed on while we were away, the fleas continue to hatch, laying in wait for a host. Adult fleas find hosts by detecting vibration from movement, pressure from being laid upon (as in a bed or nest), body heat, noise, or carbon dioxide from breath; all of which are signs that a blood host is near.

Most flea bites on people occur around the ankles and legs. Depending upon individual sensitivity, the irritation from the bites may last from a few minutes to a few hours or even days. The typical flea bite may appear as a small, hard, red, slightly raised or swollen itching area. There is a single puncture point in the center of the red spot. Ants and spiders leave two tiny puncture points when they bite. Bed bugs, bees, wasp, and mosquitoes leave a large swelling or welt. With some magnification, one may be able to identify what bit us.

Flea bites may transmit pathogens that cause disease in people as well as other animals. Cat and dog fleas are intermediate hosts for a tapeworm, Dipylidum Canimum. If fleas infected with this tapeworm are accidentally eaten, it will infect pets as well as people (especially children). A flea bite may cause irritation which is caused by saliva injected into the puncture wound to prevent blood from coagulating. People highly sensitive to flea bites should consult their physicians. Minor irritation may be soothed with calamine lotion, ice, carbolated Vaseline, menthol, or camphor.

The role of fleas as pests and disease spreaders throughout human history is some times overlooked. The bubonic plague, a bacterial disease transmitted to people by fleas, may have caused more human grief than any other single cause. It may, in fact, have changed the course of human history more than any other driving force. This plague has caused millions of human deaths. Three main plagues have been recorded in history: The first in 542 which lasted 60 years; 1346 to 1665 - a long time due to the traveling of the plague back and forth around Europe; and again 1880 killing 1 million in India before it was stopped in 1903 by modern medicine.

Recently, bubonic plague was diagnosed in two people in New York City which was what prompted research into this article. It was determined that the infected people received their infection in the southwest. Rodents in the southwest still carry bubonic plague. An interesting account of bubonic plague and rodents in the southwest, well researched by novelist Tony Hillerman, is described in his mystery thriller about the Navaho Tribal Police called "The First Eagle". The Penn Yan library has the book.

How do we protect ourselves from the scourge brought with this pest? Follow simple indoor and outdoor sanitary practices such as coordinated regular vacuuming of carpets and furniture with a brush scrubbing vacuum cleaner (one that has rotating bristles) and by keeping pets flea free. Pet sleeping areas will have the highest concentration of flea eggs and larvae so these areas need special and regular attention.

The best advice on how to handle fleas on domestic pets can be obtained from your pet's veterinarian. Store shelves are jam packed with a wide variety of over-the-counter flea sprays, lotions, soaps, powders and collars. Whether they all perform as claimed is an interesting question that we cannot answer. That is why we recommend pet owners in need of flea infestation chemical control seek professional guidance from local veterinarians; especially so if there are small children in the home. Always read and follow label directions and keep all chemicals well out of reach of children. Children can easily come in contact with chemicals applied directly on pets for flea control or from residue chemicals left on carpets and furniture where treated pets have laid.

Pest free pets are a wonderful addition to family life if one is so inclined to that kind of companionship. It is also wonderful that we have resources to assist us in making them pest free. Your pet will love you and your own life will be a healthier one in the bargain.

For all your lawn and garden questions call the Master Gardeners at the Cooperative Extension Office (315) 536-5123 leaving your name, question, phone number, and a time we may return your call with the results of our research. If you are interested in becoming a Master Gardener, a new class will be forming in January. Call the Cooperative Extension Office for details.