Fact Sheet on Fleas

email: uge1067@arches.uga.edu

Adult flea

INTRODUCTION: 

BIOLOGY:

Fleas can be an important nuisance in the summer and fall outdoors. They can be a real problem indoors all year long. Fleas are parasites in the insect Order - Siphonaptera. Siphonaptera means a tube with out wings or a wingless straw referring to the piercing, sucking mouthparts used to suck blood from their 'host' animal. There are close to two thousand different flea species with more than 250 of them in North America. They have been around for millions of years. Fleas are often given common names that refer to the host they are found on, such as: dog flea (Ctenocephalides canis), cat flea (C. felis), squirrel flea (Diamanus montanus), Oriental rat flea (Xenopsylla cheopis) or human flea (Pulex irritans). Common names may be confusing because one flea species may actually be found on different hosts, for instance the cat flea is the main flea found on both cats and dogs. Besides sucking blood and causing allergic reactions fleas are known to transmit diseases to both humans and animals. Some species of fleas are the vectors of murine typhus, tularemia and plague. Bites on people are usually around the lower leg area, but can be found elsewhere on the body, and may be accompanied with minor pain. The formation of a small, red, itchy spot surrounded by a halo may arise at the site of the bite. The severity varies with individual sensitivity and may include some swelling at the site of the bite. Highly sensitive people should seek assistance from a physician. Pets bothered by fleas may create sores on their skin from continual biting and scratching to get at the fleas. Adult fleas may only represent 5% of the population. So eggs, larva and pupa waiting to continue the cycle are the largest part of the problem. Fleas are excellent jumpers, leaping vertically up to seven inches and horizontally thirteen inches. (An equivalent hop for a human would be 250 feet vertically and 450 feet horizontally.)

Fleas have four stages in their life cycle: egg, larva, pupa and adult. Adult fleas are about 1/8 inch long, wingless, and have three pairs of legs. The adult usually remains attached to the host for the rest of its life, about two weeks, unless they are groomed off. Fleas are flat from side to side and can easily move about in the hair of its host. During that time the female lays eggs, up to 20+ per day. the female flea can lay up to 600 eggs during her lifetime. The eggs drop off the animal and hatch on the ground, carpet or animal bedding. Fleas are sensitive to humidity. They mainly develop in burrows or living spaces where the humidity is above 50%. Eggs hatch in one day to less than two weeks. The newly hatched larva looks like a tiny hairy maggot. It lives off the droppings from the adult fleas and other organic material in the carpet, animal bedding or where the eggs fell. It does not feed on blood. They are blind and avoid light so you need to look carefully deep in the pile of carpet to see them. Flea larvae take about two weeks to develop, but under unfavorable conditions it may take up to 200 days. When fully developed the larva turns into a quiet stage, the pupa. The larva spins a silken cocoon covered with debris. The adult flea develops inside this pupal stage. The pupal stage may be as short as a week or much longer. The adult remains within the pupal case until environmental conditions are favorable to its emergence. This can be a short period or many months. The stimuli for the adult to emerge are warmth, vibration and carbon dioxide, all items present as an animal (or human) passes by. It is this delayed emergence that causes an area, which has had no animals for a time, to be able to suddenly have a flea problem. Fleas and bites may occur on people or pets that have recently moved into a house that has been unoccupied for 2 or more months. The prior occupants probably had pets with fleas that laid eggs that developed to the pupal stage. The new adult remained in waiting inside the pupal case until a food source (the new occupants) came along. It is this capability plus the fact that pesticides don't penetrate the egg or pupal case that makes control a difficult challenge. Once the adult emerges it immediately is ready to jump onto the next animal that passes. Once on board it will start taking blood meals and laying eggs. The adult must have a blood meal to survive and lay eggs. But it may go from two months to a year without a blood meal.

Control fleas as soon as the problem is noticed. Left alone the fleas will soon multiply to major problem proportions. It is of no use to try to control fleas by only attacking the pest on the animal or in the yard. To control fleas requires a simultaneous, multi-pronged attack. It is best to involve your veterinarian in your pet's flea control program, especially with better control available with some of the new chemicals available only through prescription. 

1. Check pets frequently and thoroughly for fleas by combing their fur.
2. If the pet has fleas have a vet treat it or prescribe flea medication.
3. Carefully vacuum the area inside where fleas are found or where pets roam freely. Seal and dispose of the vacuum bag or contents immediately after vacuuming.
4. Wash bedding material and treat pet bedding areas.
5. The house and yard, especially animal pens, bed or resting areas, should be spot treated at the same time as all the pets.
6. Wear repellents while in the yard or field areas.
   

Pesticides can be dangerous around pets, children, the elderly and the infirm; follow label instructions and your veterinarian's guidance. Because the pesticides available generally do not control the egg or pupal stages treatment may need to be repeated until control is successful. This may take many months depending on the severity of the problem. Flea collars will not control an existing infestation and some pets have an allergic reaction to the pesticide. 

For ongoing control some of the new methods available by prescription only from your vet appear to be a major leap forward. The new treatments available, most by prescription only from your vet, show some real promise. Some are once-a-month topical applications (called spot-on) that do not wash of even with bathing. The action is to disrupt the nervous system of the flea before it even has a chance to bite your pet. While it doesn't kill the other stages it short circuits the life cycle. The data on the toxicity of these on humans and animals is very enheartening. Additionally, these affect only those pests on your pets and not the good bugs as well as well as the bad, unlike most  treatments. One method of action is with the use of an insect growth regulator (IGR) that disrupts the insect's endocrine system. IGRs prevent eggs from hatching and larvae from pupating but do not affect adults. An Insect Development Inhibitor (IDI) is another chemical that prevents fleas from completing their development and breaks the cycle, but does not control adult fleas. These type of chemicals may prohibit the formation of chitin, the main component of insect exoskeleton. Work with your veterinarian for the best protection for your family and pets. And be sure to follow label instructions and your vet's directions carefully.

'Natural' products for flea control are also available. Be sure to read the label. remember that natural does not mean the same as safer or nontoxic. Some of the natural pesticides are more toxic than most of the manmade chemicals. Use with caution. Home remedies are often untested and may be hazardous to your pet or your family.

Fleas may continue to attack your pets or you because strays or your neighbors free roaming pets continually reinfest areas, as do wild animals. So treatment with a pesticide to control the adults may be required occasionally.

Ultrasound devices are ineffective in the control of insects, including fleas.

2. Fleas, HYG-2081-97, http://www.ag.ohio-state.edu/~ohioline/hyg-fact/2000/2081.html

3. Stinging and Biting Pests of People, http://www.ces.uga.edu/pubcd/c782-w.html

4. Fleas, http://www.colostate.edu/Depts/IPM/natparks/fleas.html

5. Ridding Your Home of Fleas, http://www.uky.edu/Agriculture/Entomology/entfacts/struct/ef602.htm

6. Everything you wanted to know about fleas, but were afraid to ask, http://www.homevet.com/petcare/flea.html 

7. Fleas and Flea Control, http://www.vetmed.iastate.edu/units/vth/noxon/flea.html

The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.

Arnott 07/10/00