Parasites In Our Pets

Medically Reviewed by Dr. Lauren Stayer, DVM on August 12, 2026

Parasites are a year-round concern for dogs and cats in Central Oregon, even though most owners only start thinking about them once the weather warms up. As spring and summer bring pets outdoors more often, exposure to parasites on the skin, such as ticks, lice, and fleas, and parasites inside the body, such as giardia, tapeworms, roundworms, and heartworms, all become more likely.

At Pawtown Veterinary Care, we see the full range of these parasites in our Bend clinic throughout the year. Understanding what each one looks like, how pets pick them up, and how to prevent them can save you a stressful trip to the vet and keep your pet more comfortable.

External Parasites in Central Oregon

Ticks

Ticks are very common in Central Oregon in the spring, and after a warmer winter, we can see them as early as the beginning of February. Ticks are carried by wild animals, including deer, so it is entirely possible for a pet who never leaves town to pick one up on a walk. Ticks can carry diseases such as Rocky Mountain spotted fever, Lyme disease, and ehrlichiosis, all of which can be difficult to diagnose and treat once a pet is infected. Checking your pet after any time outdoors, especially around the ears, neck, and between the toes, is one of the simplest ways to catch a tick early.

Lice

Lice are species-specific, so a dog with lice cannot pass them to a person or to a cat. We often see lice in the spring and fall when there is some moisture in the ground, and most dogs pick them up at a park, since adult lice and their eggs can survive in grass. Lice cause intense itching, and a pet with a heavy infestation may develop hair loss or skin irritation from constant scratching.

Fleas

There is a persistent myth that fleas do not exist in Central Oregon. That is not true. While fleas are less common here than in the Willamette Valley, a pet that only lives in Central Oregon and never travels can still pick up fleas. Fleas are skilled at hiding in fur, so a light infestation is not always obvious, and pets with only a few fleas may show only mild itching rather than the more visible signs of a larger infestation.

For dogs and cats, Pawtown Veterinary Care carries Credelio, a once-monthly oral chew that protects against fleas, ticks, and lice. If your pet does pick up fleas or lice, your home environment usually needs some cleanup alongside treatment, so ask us about the specific steps needed to fully clear an infestation. If you travel with your pet during the winter months, year-round flea and tick prevention is still worth discussing, since destination climates may carry a higher risk.

Internal Parasites in Central Oregon

Giardia

Giardia is the most common internal parasite we see in dogs in Central Oregon. It is a protozoal parasite picked up by drinking contaminated water, often from a small pond or puddle, or by eating another animal’s stool. Some dogs with giardia develop diarrhea, some have only soft stool, and others show very few symptoms at all. A fecal test any time your pet has abnormal stool, plus an annual screening, helps us catch it early. There is no way to prevent giardia entirely, but cleaning the environment thoroughly is an important part of clearing an infection once it is diagnosed. For a closer look at symptoms and treatment, see our in-depth guide to giardia in pets.

Tapeworms

Tapeworms are the most common internal parasite we see in cats in Central Oregon. Cats pick them up by hunting or by ingesting fleas, since fleas can carry tapeworm larvae. A small tapeworm infection may not cause any symptoms, but an untreated cat can eventually develop soft stool, vomiting, or weight loss. A monthly dewormer combined with flea prevention keeps most cats protected. As a dewormer, Pawtown Veterinary Care carries Profender, a once-monthly topical product for cats.

Roundworms

Roundworms are very common in puppies and kittens and are also picked up by eating another animal’s stool or through hunting. Symptoms can include diarrhea, vomiting, or visible worms in the stool. Every puppy and kitten should be dewormed and have a fecal test to confirm the infection has cleared, and adult pets benefit from an annual fecal screening as well. A monthly dewormer is a smart habit for active Central Oregon pets who spend a lot of time outdoors and are more likely to come in contact with parasites.

Heartworm

Clients often ask us about heartworm risk in Central Oregon. Heartworm infections are uncommon in dogs who never leave the immediate area, but heartworm is present in nearby regions our pets frequently visit, including southern Oregon and the Willamette Valley. Heartworms are spread by mosquitoes during warmer weather and are diagnosed with a simple blood test. By the time a dog shows symptoms, there is usually already a significant worm burden in the bloodstream, and advanced cases can be fatal, which is why prevention matters more than treatment after the fact. At Pawtown, we recommend Interceptor Plus, a once-monthly oral chew that covers tapeworms, roundworms, hookworms, whipworms, and heartworm together. Learn more about our approach on the heartworm prevention and treatment page.

How We Screen for and Prevent Parasites

Annual fecal testing and bloodwork through our diagnostic services let us catch most internal parasites before they cause visible symptoms. The Companion Animal Parasite Council recommends year-round parasite prevention and at least annual testing for every dog and cat, regardless of lifestyle, since exposure risk changes with travel, weather, and wildlife activity from year to year. If you have not discussed a parasite prevention plan at your pet’s last visit, our flea and tick care team can put one together based on your pet’s specific routine.

If you are also dealing with a specific diagnosis, our dedicated article on intestinal parasites in Central Oregon covers the internal parasites above in more depth.

Frequently Asked Questions About Parasites in Pets

If you have any questions about internal or external parasites, or you are not sure your pet’s current prevention plan covers everything they need, please reach out to us at Pawtown Veterinary Care. Request an appointment and we will help you build a plan suited to your pet’s specific lifestyle and risk level.