Fleas
Introduction
Fleas are one of the most common and most problematic ectoparasites (parasites that live on the outside of a host) infesting dogs and cats. Fleas are microscopic wingless insects that occur on almost every mammal and do not seem to have much host specificity. The same flea that infests your dog can also infest you, your cat, a raccoon, etc. The most important flea found on cats and dogs in North America is Ctenocephalides felis, commonly known as the cat flea.
Flea Allergy Dermatitis
When a flea lands on your pet, it injects it's specialized mouthparts into his skin and begins to suck blood. During this process, some flea saliva is injected into your pet. Many dogs and cats are allergic to flea saliva and suffer from flea allergy dermatitis (FAD). A single bite from a flea is enough to cause an allergic animal serious discomfort. Your pet will be vigorously biting, scratching, or licking himself to alleviate the discomfort. Often, you will not find fleas on an animal suffering from FAD due to this excessive grooming. However, the presence of "flea dirt," which is actually flea feces, indicates that fleas were recently present. Flea dirt looks like tiny black or red specks on your pet's skin. Dogs and cats suffering from severe FAD may sometimes have areas of reddened, swollen skin with no hair. The best cure for FAD is to remove all fleas from the pet's body. The best prevention for FAD is to stop fleas from biting your dog or cat. If the pruritis (itching and reddening of the skin) is severe, your veterinarian may also recommend a medicated bath, antibiotics, or anti-inflammatory drugs.
Flea Life Cycle
There are four stages to the flea life cycle: egg, larva, pupa, adult. The adult flea attaches to your pet and feeds on his blood as an energy source, all the while laying eggs which drop off of your pet and fall into the environment. These eggs usually develop into larvae in the bottom of thick carpet, cracks in wood floors, cracks between your walls and floors, and many other dark, damp places in your home or backyard. The larvae survive on flea droppings (flea dirt) and pet dander present in the environment. These larvae then develop into pupae, and then adults, which can hop right onto a pet or human in the household. However, adult fleas do not hop from host to host as is commonly believed. The pupae are the source of additional flea infestations in your home. If you have a flea infestation in your home, it is important to treat your pets and the environment that you live in to rid yourself of the flea problem.
Flea Control and Prevention
There are a variety of insecticide formulations available for initially removing adult fleas from your pet. These include sprays, dips, shampoos, and very effective oral drugs available. It is important to try to remove as many flea larvae from the environment as possible. This can be partially accomplished by thoroughly washing all of the pet's bedding. A vacuum cleaner can be especially effective in removing flea larvae. In some cases, such as in a severe flea infestation or if your dog has a severe case of FAD, residual acting insecticides or other chemical solutions may be necessary. In this case, it is recommended that you consult with a professional exterminator about your options. In other cases, you can place all of your pets on flea preventative and allow them to scoop up all of the fleas in the house. This will effectively stop the flea reproduction, and eventually eliminate the flea problem in your home.
Many of today's popular flea preventatives work as inhibitors of flea development, effectively stopping the vicious cycle of adult-larva-pupa-adult. Some drugs work by killing the adult fleas within the first 12-24 hours that a flea is on the host, before they have an opportunity to reproduce. Other drugs work by directly inhibiting reproduction by killing the flea embryos or disrupting chitin formation. Chitin is a compound that makes up many insect exoskeletons. It is a good target for insecticides because mammals do not have chitin and thus there is a low risk of toxicity. Your veterinarian can recommend the right drug for you and the duration of time that you should be treating your pet. They can also recommend a drug to use for prevention and when preventative medication is required in your area. Hopefully, with prudent use of these new preventatives, you and your pets will never see a flea!