Summer Safety: Parasite Prevention


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Why do you take your beloved furry friends to the local vet hospital for a wellness exam once or twice a year? Is it because they’re due for their shots? Did you get a reminder card in the mail? Did you ever think that there might be more to these annual visits that your veterinarian should be addressing?

It’s always funny to me when clients come in and say, “I’m just here to get Bella her shots.” Annual or semi-annual exams should encompass more than just vaccinations. The intended purpose is to cover a variety of topics related to preventative medicine (similar to when you see your medical doctor once a year). What is preventative medicine? Basically, it’s a medical assessment of the health risks an individual patient might face in his or her lifetime, followed up with recommendations to prevent future disease.

Broad category topics that I like to address with each wellness visit include vaccines, parasite prevention, nutrition, dentistry, behavior and reproduction. Each category may need more (or less) attention, depending on the age of your pet, sex, breed, where you live, whether you travel with your pet, if he is indoor/outdoor, etc. And this explains why everyone in the vet hospital always asks so many questions— we’re not just being nosy. We’re trying to predict all the potential diseases and issues from which we might want to protect your beloved pet.


As summer approaches, I tend to get more questions about one of those key wellness concerns: parasite prevention. Especially here in the Coachella Valley, owners who plan on traveling to escape the heat have many questions about parasite prevention. Should my dog be on flea or tick prevention? Should I buy heartworm products? Is one product better than another? My cat is indoor only—does she really need preventative medication? And it doesn’t make it any easier for these pup parents and feline friends to make decisions when there are hundreds of different products marketed for various parasites.


One useful tool is the online website, which is endorsed by the Companion Animal Parasite Council (CAPC). It can illustrate for pet owners the prevalence of different parasites in different regions of the country, in those locations where you may be planning a visit. This will arm you with good information about what your pet may be facing as you spend time in that region.

Forecasted Prevalence of Lyme Disease

So what is the deal with all the parasite products, anyhow? Are veterinarians just trying to make money off their clients by selling their favorite “merch”? Not really. In part, the rise in the number of available parasite protection products is a result of pet owners looking for catch-all products that will protect against multiple parasites, which varies for different parts of the country. For example, one class of drug, Isoxalaxines—which includes products like Nexgard, Bravecto, Simparaca and Credelio—can be used to treat fleas, ticks, and mites. These drugs are often attractive to veterinarians because they have a relatively high speed of kill rate for adult fleas. However, if a puppy comes into the clinic with a high flea burden, we would want to select a product that’s approved for puppies with an even more rapid kill rate, such as Capstar. This would rid the puppy of the adult fleas, but it would not provide future protection since the medication only lasts a day or two. It’s important to consult with your veterinarian before you apply any preventative to your pet’s coat. Formulations vary, and the wrong one can be hazardous to your pet.

The tables on page 52 show a few of the many products on the market that are widely used for parasite protection. They are by no means exhaustive lists of available products—they are just a sampling of the formulas available.

As mentioned earlier, multiple factors must be considered before choosing a preventative— age, route of administration, speed of kill, targeted parasite species, drug class, etc. This is the benefit of consulting with a veterinarian—it’s our job to be aware of and have an understanding of these drugs. Some drugs may have risks only for certain breeds, such as Ivermectin drugs (used for heartworm) in collies. Collies and a few other breeds can have hypersensitivities to Ivermectin if they have a specific mutation. Another example is the Isoxaline family of drugs mentioned previously. These may be contraindicated in patients that have neurologic diseases, such as seizures, because these drugs kill the arthropod (flea/tick) by targeting the nervous system. Topical products like Frontline or Advantage Multi may become less effective after bathing or swimming, as the product will be at least partly washed off. Additionally—and especially important for those of you who are traveling to places with increased heartworm risk— these drugs act retroactively. This means that many heartworm products are killing heartworm larvae that your dog or cat may have gotten from a mosquito bite a month ago. They do not continue to kill larvae after being ingested or applied to your pet. So if you go on vacation with Fluffy to Miami, be sure to continue to give her heartworm preventative for several months after you return home.

Fleas, ticks, and heartworm tend to get the most coverage relative to the numerous other parasites to which your dogs and cats could have potential exposure. These include parasites such as roundworms, tapeworms, whipworms, giardia, toxocara, demodex mites, mange mites and many more. Fortunately for you, a good number of the products that protect against heartworm or fleas and ticks also provide protection or treat these parasites, too. While we have examined a number of common preventatives that veterinarians will frequently prescribe here, keep in mind that very few hospitals can stock the continually expanding repertoire of parasiticides. So, consult your veterinarian this summer for a recommendation and explanation of the products they carry, and use the one formulated especially to keep your dog or cat safe while ridding them of those pesky parasites.

If you’d like more information on parasite prevention, Pet Companion Magazine has previously published articles by my colleague Dr. Robert Reed, with in-depth coverage of heartworm, ticks, giardia and other parasites. You can access those articles online at


Dermacentor variabilis

WHERE FOUND Widely distributed east of the Rocky Mountains. Also occurs in limited areas on the Pacific Coast.

TRANSMITS Francisella tularensis (tularemia) and Rickettsia rickettsii (Rocky Mountain spotted fever).

COMMENTS The greatest risk of being bitten occurs during spring and summer. Adult females are most likely to bite humans.


Rhipicephalus sanguineus


TRANSMITS Rickettsia rickettsii (Rocky Mountain spotted fever). Primary vector for R. rickettsiitransmission in the southwestern United States and along the U.S.-Mexico border.

COMMENTS Dogs are the primary host for the brown dog tick in each of its life stages, but the tick may also bite humans or other mammals.


Ixodes pacificus

WHERE FOUND In the Pacific Coast states.

TRANSMITS Anaplasma phagocytophilum(anaplasmosis), B. burgdorferi (Lyme disease), and very likely B. miyamotoi (Borrelia miyamotoi disease, a form of relapsing fever).

COMMENTS Larvae and nymphs often feed on lizards, birds, and rodents, and adults more commonly feed on deer. Although all life stages bite humans, nymphs and adult females are more often reported on humans.


Additional Resources:

You may also want to check out these websites that show parasite incidence or prevalence forecast maps:





VCA Rancho Mirage Animal Hospital located at 71-075 Highway 111, Rancho Mirage, CA. (760) 346-6103. Visit


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