Our Foes, The Fleas by Debbie Eldredge, DVM Good Dog!® Magazine www.gooddogmagazine.com
One of the most worthy foes we face in veterinary medicine is the lowly flea. This insect has driven people and their pets crazy for centuries. Maybe we're finally gaining the upper hand, though, with some of the developments over the last 15 to 20 years. A review in the April, 1999 Compendium of Continuing Education reminds us of some of the highlights of this campaign. First, it should be noted that the most common flea we encounter is Ctenocephalides felis, the cat flea. Luckily this flea has not been shown to carry bubonic plague, which caused so much death in the Middle Ages. It can still create discomfort and allergic reactions, however, and the itching and chewing can lead to serious skin problems. It wasn't until the 1980s that scientists really began to study fleas and figure out their life cycle and habits. Fleas are semi-permanent residents of the animal they call "home." They eat blood meals from your dog, breed on your dog, and lay their eggs on your dog. These eggs then fall off and the resulting larvae head for deep, dark places -- like the bottom of your carpet. While fleas can't survive freezing temperatures on their own, they do enjoy your central heating or the warmth of a raccoon's coat outdoors. If conditions are poor, development can be delayed for up to 6 months. You can stimulate a major hatchout by walking into a house that has been empty for months; the fleas can sense a possible host. While it may seem unbelievable to you, it took major efforts to develop systems to raise fleas in a controlled laboratory environment. It's not easy to duplicate your dog or cat. Once this was accomplished, controlled studies with different treatments as well as reproductive research, could be conducted. These studies showed that, because larvae go deep into your carpet, most surface treatments don't work very well. Reproductive efforts demonstrated that insect growth regulators could be helpful in controlling fleas, and that treatments could potentially be applied to your pet since the fleas choose to reside there as much as possible. Years ago, our flea control involved being reactive -- we waited and hoped we wouldn't notice any fleas, but when we did, we flew into full battle plan. We bathed, dipped, sprayed or powdered our pets while also spraying or powdering our homes and, sometimes, even our yards. We still may occasionally do all this for a severe problem or for someone with many pets. Now, however, we have newer, safer and highly effective weapons. One of these is lufenuron (Program® and Sentinel®). This is an insect development inhibitor which keeps flea larvae from developing into full grown fleas. It won't kill adult fleas, but it will keep things under control. And it's quite safe. This can be ideal for people who don't normally have a flea problem, but don't want one to show up, either. Given orally (although there's a new injectable form out for cats) once monthly, lufenuron can keep you from establishing a flea colony. For an active problem, or a pet with flea allergy, this may not be enough. There are new products out which can repel and/or actively kill fleas before they have the chance to lay eggs -- imidacloprid (Advantage®) and fipronil (Frontline®). These are applied to the skin of the dog and spread by themselves. Frontline also works on ticks. These are effective anywhere from one to three months and are now even fairly resistant to the swimming efforts of your canine companion. Side effects seem to be minimal. I admit to being skeptical when these products first came out -- after all, I've felt all along that the only way to get rid of fleas was to find a use for them. You just know that if fleas were worth money, you wouldn't have any! I did try them on my own pets, though. My barn cats have had a topical flea product for the warm months here in upstate New York for 3 years now. I've never seen a single flea in all that time. I tried the combination flea/tick product on one of my dogs when we headed for an agility trial in Massachusetts. The year before, I removed 23 ticks from Beep and 3 from me. After using the new product, there were no ticks on Beep -- and I still had to pull 2 off me! So I'm sold on the new flea control methods. I apply the topical (skin) products right before I go to bed at night, so that by the next morning, when the kids are up, I figure the dogs are safe to hug (even though these products are very safe for people). My only fear now is that the clever and adaptable flea will develop resistance to these new treatments, as well! Good Dog!® Magazine |