WebMD veterinary experts answer commonly asked questions about fleas and ticks on your dog.
Although there are more than 2,200 kinds of fleas, it only takes one type to cause a lot of misery for you and your pet. We went to internationally known flea and tick expert Michael Dryden to find out how to fight fleas and eliminate ticks. Dryden has a doctorate in veterinary parasitology, is a founding member of the Companion Animal Parasite Council, and has conducted research on almost every major flea and tick product on the market.
Q: How did my dog get these fleas and ticks?
A: The way animals get fleas is some other flea-infested animal – a stray dog or stray cat, or some other neighbors’ dog or cat, or urban wildlife, mainly opossums and raccoons – went through your neighborhood, your yard, and the female flea is laying eggs and the eggs are basically rained off into your environment. We call them a living salt shaker. And then those eggs developed into adults and those fleas jumped onto your pet. That’s how it happened.
Dogs generally get ticks because they’re out in that environment, walking through the woods or high grass, and these ticks undergo what’s called questing, where they crawl up on these low shrubs or grass, generally 18 to 24 inches off the ground and they basically hang out. And when the dog walks by or we walk by and brush up against these ticks they dislodge and get onto us. Ticks don’t climb up into trees. That’s an old myth. They just lie in wait for us. It’s sort of an ambush strategy. They can live well over a year without feeding.
Q: Can fleas and ticks cause my dog to get sick? What kinds of illnesses can she get from them?
A: Probably the most common thing is, when these fleas are feeding, they’re injecting saliva into the skin. These salivary proteins are often allergenic and animals end up with allergy. The most common skin disease of dogs and cats is what’s called flea allergy dermatitis, where they bite and scratch and lose their hair. It can take only a few fleas for this allergy to become a problem.
If you have a lot of fleas, since they’re blood-sucking insects, especially if you have puppies, pets can become anemic and even die with heavy infestations. Fleas also commonly transmit tapeworms to our pets, at least one species.
With ticks, there are a dozen to 15 or more tick-transmitted diseases that our pets get from ticks. There’s Lyme disease, Rocky Mountain spotted fever, tularemia, ehrlichiosis, and more. Many of these diseases can kill pets.
Q: Are fleas and ticks worse in some areas? Where?
A: Ticks and fleas can be worse from one area to another and can vary seasonally and from year to year. There’s one particular flea species that we find on dogs and cats in North America that predominates … called Ctenocephalides felis, or the cat flea. That flea is very susceptible to drying. So that’s why there are more fleas in Tampa than in Kansas City, and more fleas in Kansas City than Denver. Once you get into the Rocky Mountain states, for example, or even the Western areas of the plains states, fleas on dogs and cats are not that much of a problem because it’s just too dry. The Gulf Coast region of North America and the Southeast region are the flea capital. As you move inland, however, depending on the rainfall in a given year, it can be OK or get very horrid at times.
Ticks have different biologies and behaviors, of course. And certain areas have more tick problems than others. The upper Midwest and the extreme Northeast, from Pennsylvania up, have a very serious problem with the Lyme disease tick. But if you get down to the south central part of the United States, ticks also can be absolutely horrible. There are very few places in North America you can’t encounter ticks today, because there are so many different ticks.
Q: Can I stop using preventives in winter months, when all the fleas, ticks, and mosquitoes are dead?
A: It depends on where you’re located. In most of the United States, my answer today is “No” for various reasons. There are so many different tick species, and fleas can be a problem even late into the fall. If you get into some of the more northern states or into Canada, where they have very long, protracted winters, then it could be reasonable for several months. But even here in Eastern Kansas I don’t recommend stopping. We’ve only got about 40-45 days a year when we don’t see ticks.
Q: I know about Lyme disease and Rocky Mountain spotted fever, but now I’m hearing about new diseases my dog can get from ticks. Are these diseases rare? How worried should I be about my dog contracting a tick-borne disease?
A: It depends on where you live. Some of these diseases are local. What you have to do is, depending on where you live, talk to your veterinarian and find out what diseases are important in your area. The diseases that are important to dogs and cats in Kansas are not the same diseases that are important to dogs and cats in Connecticut.
Q: An environmental group has sued several pet stores and manufacturers claiming that flea collars have high concentrations of chemicals in them that are dangerous to pets and people. Are these over-the-counter flea collars safe?
A: I’m not a toxicologist and I try to steer clear of all that. But I will say that I believe the best way to manage fleas and ticks is go to your veterinarian and find out what products they recommend for your area. The issue we have with many of the over-the-counter products is that many are what we call pyrethroids, or synthetic pyrethrins. We know that is a class of insecticides that fleas are commonly resistant to, so one of the reasons over-the-counter formulations don’t work very well is that fleas are resistant to them. What that leads to is people tend to over apply them because they didn’t work that well and then you tend to have problems.
Q: There are also reports that the EPA is looking into an increase in adverse reactions from topically applied flea control products, the ones we usually put on our dogs and cats between their shoulder blades. So are these unsafe?
A: I generally believe, based on my experience and our field studies, that the products we get from our veterinarians are generally very safe and generally do a very, very good job. But you’ve got to understand that millions of doses are used each year. With that many doses, things happen. Do rare reactions occur? Absolutely. We know they do. But generally with a veterinary-recommended or prescribed flea or tick product, if they are used according to label directions, they are extremely safe in my experience.
Q: What are the best ways to control fleas and ticks?
A: Besides the flea products we’ve discussed, if you have a cat, don’t ever let it go outside. Try to keep your home as dry as possible. I would recommend not having any carpet because carpet is a flea’s best friend. Keep the brush and weeds in your yard to an absolute minimum.
Q: Are there natural ways I can control them if I don’t want to use chemicals?
A: There really aren’t from a natural standpoint. Over the years, we’ve spent some time looking into the more natural or holistic approaches and as yet I’ve not found any that’s actually effective. The garlic, the brewer’s yeast, all the research shows none of that stuff works. If it did, I’d be using it. The ultrasonic devices? The data shows they don’t work.
And just because something is “natural” or “organic” that doesn’t mean it’s safe. Most of the poisons in the world are actually organic poisons. Some of these citric extracts people used to use can be fairly toxic to cats. The cats’ livers just can’t handle them.
There is diatomacious earth, which is basically microscopic silicone particles that can be spread around in your carpet. They scratch or excoriate the flea larvae. But you’ve got to be a little careful. You don’t want to inhale the stuff, because now you’ve inhaled silicone particles into your lungs and where’s that going to go? There are pesticide control firms that apply that stuff appropriately, and when they do it’s very effective and it’s safe. But just make sure if you have somebody do it in your house it’s done appropriately. It’s a very good larvacidal and a flea preventive measure if it’s done correctly.
Q: How can I control fleas and ticks in my yard?
A: Cut the tall grass, trim back the bushes and shrubs, then rake up all the leaf litter under the bushes. Leave it just bare ground. There are some lawn and garden insecticides that are approved by the EPA to be applied under shrubs, under bushes, in crawl spaces, along fence lines, to control fleas and ticks outside. The big issue I see is people tend to go out and start spraying their grass. That’s not effective and it’s certainly not good for the environment. Fleas and ticks are really sunlight and humidity sensitive. Most situations where we find them are under shrubs, under bushes, under porches, in shaded, protected habitats. So we should only be applying those compounds in a limited fashion under those locations. Then we’re going to let it dry on the foliage for three to four hours before we allow our pets and our children back out there.