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How Flea Treatments Work

Pet pest prevention

It's not unlikely that your pet may occasionally cross paths with a stray flea, but what if these external parasites become more prevalent? What's a concerned pet parent do? While we all know that a wide range of flea products exist, it's easier to make informed decisions when you know how these treatments work. Here we'll cover the basics of what makes these products so good at making those fleas flee.

Keep in mind that heavy infestations may require the use of more than one product or treatment. Some products target only one portion of the flea life cycle, with some offering immediate relief from adult fleas while others break the life cycle by targeting eggs or larvae development. In the case of a serious infestation, a multi-pronged approach may be necessary. Be sure to discuss all flea treatments with your veterinarian, who can provide advice based on your pet's age and current health status.

With all flea treatments, be sure to precisely follow the manufacturer's directions, and never use dog-specific products on cats and vice versa.

1. Flea shampoos

Flea shampoos contain additional ingredients that repel or kill fleas. There are also flea shampoos that contain natural ingredients, however many of these products may not provide the same levels of efficacy as medicated products. Also, while flea shampoos can help, they are not effective as your only flea prevention strategy.

2. Spot-on treatments

Spot-on treatments (available in both over-the-counter and prescription varieties) are a liquid medication that is applied directly to your dog's skin (where and how can depend on the manufacturer), usually in an area that your dog cannot lick, such as behind the neck or along his back. Once applied, the ingredients are absorbed into the oil glands of your pet's skin, which then spread out and begin to kill fleas all over your pet's body. Spot-on treatments have the advantage of becoming active quickly and staying active for a specified period of time (check the packaging for manufacturer's recommended reapplication timeframes).

3. Oral prescription products

Oral prescription flea solutions work in different ways. Most of these treatments are very effective because they contain both an insecticide, which kills adult fleas, as well as a hormone growth regulator which targets eggs and larvae. However, some oral prescriptions contain only one or the other so you'll need to do your homework to make sure your ridding your pet of both adult and developing fleas. Hormone growth regulators kill fleas over long periods of time by disrupting the flea's exoskeletal development; they can be effective for all growth stages of fleas by preventing the hatching of eggs and interfering with the molting process—and in effect, the growth—of flea larva. However, they don't necessarily kill adult fleas so they are often used in conjunction with other flea products. Again, the “multi-pronged” approach works more quickly to eliminate adult fleas.

4. Flea collars

Flea collars work by either emitting a pesticide into the area around your pet or releasing one that is absorbed by your pet's skin. While some are effective, many, unfortunately, only protect a very small portion of the animal, generally around the neck area. Additionally, prolonged use is more likely to cause a localized skin reaction where the collar is worn. Flea collars can be quite handy in the event of a flea infestation; simply toss in your vacuum canister or bag for a more effective vacuuming experience.

5. Foggers

A fogger is a pressurized can of pesticide that, when released, fills the nearby environment (such as a living room) with an insect-killing aerosol. Foggers can be quite effective in eliminating fleas on surfaces and in penetrating to kill fleas lurking in crevices. A fogger's major advantage is that it allows you to deal with the fleas that are present in your pet's environment, not just those that are on them or that come into contact with them. On the downside, when using a fogger, you'll need to evacuate the area for at least several hours during the de-infestation process, and any food or cooking surfaces will need to be covered to avoid potential contamination.

6. Sprays

There are a variety of sprays on the market, and which you select will be based on your level of flea infestation. Some sprays are designed to be sprayed directly onto your pet. Others are designed to be sprayed on furniture, bedding or carpet. Still others are exclusively for use outdoors. Additionally, some sprays offer 30 days' worth of flea killing protection while others fade almost instantaneously. Be sure to read the manufacturer's guidelines for application directions.

If you are dealing with a flea infestation, don't worry, we are here to help! Visit your local Petco to find the right treatment for your pet.

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Reviewed by Petco’s Animal Care, Education and Compliance (ACE) Team

Petco’s ACE team is a passionate group of experienced pet care experts dedicated to supporting the overall health & wellness of pets. The ACE team works to develop animal care operations and standards across the organization and promote proper animal care and education for Pet Care Center partners and pet parents, while also ensuring regulatory compliance.