Heartworms, fleas, and ticks! Oh my!

Dr. Allison Kean, DVM, cVMA
HSBV Chief Clinic Veterinarian

It’s springtime in Colorado and we’re all eager to get back outside and enjoy nature!  While we have been socially distancing – our pets internal and external parasites have not.  Spring time is their favorite season, and they love to be close to you and your pets. These pesky pests can grow and spread a variety of ways.

Bugs bug us! Heartworms are spread by the bites of mosquitoes, flea bites can transmit typhus, plague, and tapeworms, and ticks can carry Lyme disease and Rocky Mountain spotted fever. These are just a few of the zoonotic (transmissible between animals and humans) diseases these parasites spread.

Bad gut feeling… In addition to being aware of hosts in the form of the creepiest crawlers, there are also environmental conditions that can cause disease and infection. Wildlife droppings, rodent infestations, still water, trash, pet waste (pick it up!), and other conditions can spread parvo virus, leptospirosis, intestinal parasites, among many other infectious diseases that can be passed onto people.

Keep wildlife wild! An important part of preventing exposure to these parasites is keeping your pets (and yourselves) away from wildlife. Even though they may seem cute and cuddly – they carry bugs, and their waste spreads parasites. While different than the parasites previously mentioned, wildlife can also carry deadly viruses like distemper and rabies. Greenwood Wildlife is an excellent resource for all of your wildlife questions and support needs.


Although preventative care may be delayed for your pet due to COVID-19, there are a wide variety of products available to help prevent your pet from becoming vulnerable to these vermin. These products can be administered in a variety of ways (topical, oral, or injectable), can change your pet’s “recipe” for wellness, as some of them interfere with other medications or preventatives, and recommendations for their use differ among species, breeds, and other considerations. Consult your veterinarian about your options and what’s best for your pet.

Some questions you can ask include:

  • What parasites does this product protect against?
  • How often should I use/apply the product?
  • Is there a need for more than one product?
  • How would I apply or use multiple products on my pet?

Parasite protection is not “one-size-fits-all.” Certain factors affect the type and dose of the product that can be used, including the species, breed, age, life style and health status of your pet, as well as any medications your pet is receiving.  Some breeds are sensitive to certain ingredients that can make them extremely ill. Flea and tick preventives and some medications can interfere with each other, resulting in unwanted side effects, toxicities, or even ineffective doses; it’s important that your veterinarian is aware of all of your pet’s medications when considering the optimal flea and tick preventive for your pet.

Below are some great websites with more information about these parasites.

Heartworm Society

AVMA Flea & Tick Resources

Companion Animal Parasite Council