Are we winning the war against fleas?

DVM Newsmagazine recently asked flea expert Dr. Michael Dryden, the E.J Frick Professor of Veterinary Medicine in the Department of Diagnostic Medicine and Pathobiology at Kansas State University (KSU), about trends in flea biology, compliance and control. Here are excerpts from the interview:

Q: Are we winning the war against fleas?

A: The simple answer to that is No. The primary reason is client compliance. Clients will not do what we ask them to do.

Particularly this time of year, we run into horrible flea problems. Most clients got lax in their flea-control applications, and now we have our classic fall flea surge. Now we have a flea problem, and we'll start treating it. It's going to take at least two or more months to get many of these homes under control.

We need to take the time to talk to the clients about the problem. By the time they notice fleas on their dog or cat, there has been a life cycle basically percolating in their house for probably six to eight weeks. Most clients don't realize you have that incredible biomass of immature stages that are just developing in that house. They honestly think that when you see the fleas and treat them, the problem will be over in a day or two. And that's not biologically possible.

Q: Is resistance to flea parasiticides emerging?

A: It's still up in the air. In the older classes, like organophosphates, resistance has been well-established. But there is no documented evidence at this time that we have truly selectional resistance against this modern array of flea products. It doesn't mean there's not resistance. It just means we can't document it at this time.

Q: Why is an understanding of flea biology important to eradication?

A: When you're treating the dog or cat, you're just treating the fleas, which is the tip of the iceberg, if you will. All those developmental flea stages in that environment are causing problems. That's where people struggle. Most clients don't understand that.

If you treat the dog today, the problem is not the fleas today, but how many flea eggs were laid yesterday. Those eggs that were deposited off that dog or cat in the home environment yesterday are not going to emerge as fleas for a number of weeks. Particularly in the fall, where climate conditions are so perfect for fleas, many homes are going to get worse before they get better. We have to get that across to people.

Once treatment has started and clients struggle through this fall, it's up to us as veterinarians to remind these people next year. "Remember last year, the problem we ran into? This year let's get your dog or cat on one of these products and never take them off."

We have to get that preventive message across. As a profession, we're not taking the time to educate our clientele. Somebody in your practice — if it's not the veterinarian, then somebody else who's trained — needs to explain to the client what the real problem is.

That is where we run into trouble. Right now what happens is, a client comes in, you treat the pet and, for the next two to three weeks or so (some as long as four weeks), it's every bit as bad as the day treatment started.

Q: Do any treatments tackle fleas in their least-vulnerable stage as pupae?

A: No. We can set off foggers and have exterminators come to the house and treat.

In effect, quite a number of the eggs and larvae can be killed, but we have to wait for the pupae to emerge as fleas and kill them when they jump on our pets.

Q: Of the diseases Ctenocepha-lides felis is capable of transmitting, which is the most concerning to you? Why?

A: Flea-allergy dermatitis. It's the primary issue we need to face. Fleas can transmit tapeworms. Bartonella henselae is a problem.

But, by and large, our biggest problem is the allergy, the irritation, that's caused by fleas.