There are many ways which our pets are affected by fleas, but the biggest impact is on their comfort. Since fleas crawl around on the skin and feed on the blood of our animals, they create an itchy sensation. For animals that have flea allergies, a reaction to a protein in the saliva transmitted while the flea feeds creates an intense itch even with a single bite. This is why if you have a pet with itchy skin, it’s important to remove fleas as effectively as possible. This can help us to rule out a true flea allergy and prevent confusion about other causes of itchy skin.

As pets groom themselves they may ingest fleas and become infected with tapeworms, an intestinal parasite. This is the most common cause of tapeworms.


Tick-borne diseases are less prevalent in the Pacific Northwest than other parts of the country. However, the Companion Animal Parasite Council is predicting a higher than average risk forecast for Lyme disease in this area for this coming year.


Heartworm disease is a life-threatening condition caused by the bite of a mosquito carrying the infective Heartworm larva. The occurrence of Heartworm disease in Portland is very low. However, the risk increases dramatically just south of Portland, especially in southern Oregon. There is great concern that the incidence of Heartworm disease in Portland will increase with time and climate change.

If you are travelling to a part of the country where Heartworm is a problem, it is possible to use a preventative during your journey. However it is important to confirm a negative Heartworm test before administering.

To determine what kind of Heartworm risk exists in the area you are planning to travel to go to the following website:

Petsandparasites.org and select Parasite Prevalence Maps.

Intestinal Parasites

Most intestinal parasites can have an effect on the digestive system, causing soft stools, diarrhea, malabsorption, and intestinal bleeding. However, symptoms can be mild or intermittent. If a pet is showing any of these signs, a fecal examination as performed by our lab is essential to rule out parasites. Humans, especially children, can be at risk if exposed to animal stools in sand boxes, gardens or just out walking barefoot in the yard. We strongly recommend fecal testing at least yearly.

Exposure to Giardia is common for dogs that drink from contaminated water sources like puddles or streams.

Salmon Poisoning is a life-threatening disease that can occur when a dog ingests raw salmon, trout, or steelhead. Fish found on the shores of rivers and on beaches are a common source.

Natural versus Pharmaceutical Strategies

We are asked regularly if there are alternative approaches to flea control. Please see our Handout on Flea Control for specific recommendations regarding a natural approach to managing exposure to fleas. These techniques take a considerable commitment of time and labor, but can be very appropriate for those who wish to avoid reliance on conventional treatments.

When is it time to go for the “Big Guns”?

There are times when it’s appropriate to use a product that has a proven efficacy.

  • Animals with chronic or severe itchy skin
  • Animals that spend time outdoors in tick infested areas
  • Animals that spend time in a Heartworm endemic area
  • Any animal for whom we would like to reduce the risk of exposure as discussed at your most recent wellness exam.

Years ago, the only flea and tick products available were very dangerous for our pets, our children and the environment. Organophosphate toxicity was a tragic occurrence. Even more tragic were the miserable pets affected by severe flea allergies that were ultimately humanely euthanized. It’s hard for us to imagine these cases with the spectrum of effective flea control that’s now available, both topical and oral. We are seeing a new generation of oral flea and tick products that are required to meet FDA safety and efficacy standards.

Nexgard  is a monthly oral flavored chew for dogs that tastes great, doesn’t need to be given with food, and is easy on the stomach. The added benefit of Nexgard is that it is effective against ticks as well as fleas. Since the Companion Animal Parasite Council has warned of a higher than average risk of Lyme disease in certain parts of the country including the Pacific Northwest, Nexgard is an excellent choice for our patients.

Cheristin is a topical version of Comfortis, available for cats. While Comfortis is still available, oral administration in cats can be tricky, making Cheristin a convenient alternative as a topical flea treatment.


Heartgard Plus is effective at preventing Heartworm as well as some intestinal parasites. Considering the life-threatening nature of Heartworm disease we strongly advise the use of this preventative with any possibility of spending time in an endemic area. If your pet is already on a heartworm preventative, you and your doctor can decide at your next wellness visit if it’s appropriate to continue. *

These products appear to be very safe for healthy patients. If your pet has a history of seizures, please discuss the options with your veterinarian before using.

The best time to discuss if your pet would benefit from parasite prevention and which products are most appropriate is at the annual wellness exam. If your pet hasn’t been seen within the last year, now is a great time to schedule an appointment for an evaluation and discussion. We unfortunately cannot prescribe anything to your pet if we haven’t examined them within the last year.

We understand that these preventatives can be costly. In an effort to offer pricing similar to on-line pharmacies, we have teamed up with Vet’s First Choice as our exclusive on-line partner. This also expands what we offer to include many preventatives that your pet may have been previously prescribed which you may want to continue. We still carry the preventatives mentioned above at the clinic for your convenience.

To schedule an appointment, request a prescription for your pet, or if you have any questions, please give us a call today.

*Heartworm preventatives and the MDR1 gene:

Certain breeds like Australian Shepherds, Border Collies, Collies, and Shelties, among others, may carry a mutation in the Multi-Drug Resistance Gene which codes for a protein that is responsible for protecting the brain from certain drugs and chemicals. Dogs with this mutation may have sensitivity to Ivermectin, the active ingredient in many Heartworm preventatives, including Heartgard. The doses in the products are generally too low to be of concern. However, testing is available to detect presence of this gene mutation.