A Bumper Crop of Parasites

Heartworms and hookworms and fleas, oh my!! Get ready- the forecast is that this year’s combination of unseasonably warm winter temperatures and plenty of springtime precipitation is going to produce a deluge of parasite problems for our pets including: heartworm disease, fleas, ticks, and intestinal parasites (roundworms, hookworms, whipworms, tapeworms).

The Companion Animal Parasite Council (CAPC) predicts a substantial nationwide rise in parasites above normal levels. Hardest hit will be the southern portion of the United States (West Virginia, Virginia, North Carolina, South Carolina, Georgia, Florida, Alabama, Tennessee, Mississippi, Arkansas, Oklahoma, Texas, and Louisiana). The CAPC anticipates that 2012 will be a “banner year” for heartworm disease, and that even the slightest deviations from administering heartworm preventive as recommended could pose significant health threats for pets.

The CAPC is also predicting a jump in parasite populations within the Northeast (Maine, Vermont, New Hampshire, Massachusetts, New York, Rhode Island, Connecticut, New Jersey, Pennsylvania, Delaware, Maryland, the District of Columbia) and the Midwest (Kansas, Missouri, Illinois, Indiana, Ohio, Michigan, Wisconsin, Iowa, Minnesota, North Dakota, South Dakota, Nebraska), particularly in areas with above-average temperatures and rainfall. During the past five to ten years, the incidence of heartworm disease has been on the rise in both the Northeast and the Midwest.

Washington, Oregon, and Northern California are expected to experience moderate increases in companion animal parasite populations this year. The parasite forecast for Southern California, Arizona, New Mexico, Nevada, Utah, Colorado, Wyoming, Montana, and Idaho is moderate compared to other regions in the country.

Sounds like there will be no hiding from parasites this year! In order to protect your dogs and cats from these pesky varmints I suggest the following:

  1. Talk with your veterinarian about the products best suited for protecting your dogs and cats against heartworm disease, intestinal parasites, fleas, and ticks. There are a variety of products to choose from and their effectiveness can change from year to year. Your veterinarian will be “in the know” about which preventive medications have the current best track record. Be reminded, animals with thick hair coats or those who are housed mostly indoors remain susceptible to heartworm disease.
  2. Be downright religious in adhering to a schedule for administration of your pet’s heartworm prevention medication. This year in particular, missing the mark by even a week or two could have dire consequences.
  3. Set up a schedule for routine testing for parasites. Your veterinarian can advise you on how frequently your pets should be screened for intestinal parasites and heartworm disease.
  4. Check out the CAPC website to have a look at parasite prevalence maps (updated monthly) and get information about your specific geographic area.
  5. Visit the American Heartworm Society website to catch up on the most current information pertaining to heartworm prevention for dogs and cats.

Are you “good to go” with a parasite prevention plan for your dogs and cats? What will your strategy be?

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at www.speakingforspot.com, Amazon.com, local bookstores, and your favorite online book seller.

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8 Comments on “A Bumper Crop of Parasites

  1. I do not give my companion animals Revolution or other spot on products since they are poisonous. I make my own spray from Neem and other oils. I also do not give heartworm preventative year round since mosquitos are not around during the winter no matter how mild. Here are two excellent articles on this issue. There is also growing evidence that Heartgard is losing its’ efficacy. as well.Also Dr. Michelle Yasson a wholistic vet recommends Heartguard be given every 3 months.



  2. As to P-glycoprotein / MDR1, Washington State University has great information and is a leader in the research.

    “The discovery of the mutation of the multi-drug resistant gene (mdr1), establishment of testing procedures, and development of all reagents was made by Washington State University. It is also a patent protected diagnostic test offered exclusively by Washington State University that has not been licensed to any other entity in the United States.’

    Here they provide a detailed guide on safe drug use.


  3. Hi Susan,
    Novartis is telling veterinarians that Interceptor will be available at some point in the future. In terms of products for herding dogs, here is what the American Heartworm Society has to say-

    Some Collies and other P-glycoprotein deficient dogs are unusually sensitive to a variety of commonly used veterinary drugs, including some antidepressants, antimicrobial agents, opioids, immunosuppressants, and cardiac drugs (Table 1). The macrocyclic lactones are also included in this list with toxicities being reported with overdosing or in combination with other P-glycoprotein inhibiting drugs. Often these instances have occurred when concentrated livestock preparations of these drugs have been accidentally ingested by a dog, or there has been administration of an improper dose to a dog, typically due to human error in dose calculation with extra-label use of these products in dogs. The standard chemoprophylactic doses have been shown to be safe in all breeds.

    Hope this helps

  4. I recently called my vet to refill my dog’s Interceptor prescription. I was hoping it would be back in stock. The pharmacist said that it had been discontinued. Do you know if that’s true, or if it just continues to be unavailable?

    In any case it will not be back in stock by the time I need it. What is a good alternative for a dog with herding dogs his genetic heritage? I’m waiting to hear back from my vet for his suggestion, but I wonder what yours would be. I have another month to decide. Pros and cons of the options would be very helpful.

  5. On the California Central Coast we have had a noticeable increase in ticks. Everyone around here is complaining, on behalf of dogs, cats, kids, and themselves. The boys (dogs) have their Advantix II on now. Normally I don’t have to put anything on until mid-June. Now, if someone would make a tick preventative for me….

  6. Ha! Well it is a whole new ball game for me. I recently moved from the jungles of Central America … to central Michigan. I figured that the parasite problem would be “minor” here — vet prescribed Revolution against HW, fleas and ticks, but the ticks are winning. They were our nemesis in Belize and unfortunately, they are pretty bad here too. So many product choices here! And always a balance between safety and effectiveness. I guess I’m going to go with ivermectin next month and figure out what to do for the fleas and ticks … Our new vet here (highly recommended by some) was not particularly helpful so I think I’m going to be looking for another vet as well…

  7. We use ivermectin based heartworm prevention monthly, year round, for both my personal dogs and the shelter dogs.

    One reason, when a dog tests heartworm positive, part of the best practice treatment from AHS is regular ivermectin until the adulticide. We have had one heartworm positive dog, and I gave him ivermectin weekly until he was ready for the adulticide. So, when we don’t know the status of a dog, it seems safe and wise to provide the ivermectin.

    However, many veterinarians still recommend a heartworm test before giving monthly ivermectin preventative. This seems a contradiction, because if the dog tests positive, ivermectin should still be given immediately, according to best practice. Is there a medical reason to wait for a test before starting the monthly ivermectin? Is there ever a condition where a dog tests positive and ivermectin should not be started immediately?

    I understand some of the other preventives can be dangerous to a heartworm positive dog, especially the older once a day pills.

    In other countries, especially Australia, heartworm preventatives are not prescription drugs. I wonder how their compliance compares to the U.S.

    Also, for deworming young puppies and kittens under 6 weeks, and nursing mothers, our veterinarian recommends pyrantel pamoate in the form of Strongid T, 0.2 ml for the young ones. Is this widely accepted as sound and safe? We later give a broader dewormer.

    Thank you for any information.

  8. We’re good to go, with exception of ticks. Still can’t figure out whether we do have a problem or not (only 3 ticks were found at our guys hang out place last fall and this spring combined; two on our dogs) and if not haven’t made up our mind about best protection strategy.