Internal and External Parasites

There are a variety of parasites (internal and external) that affect our pets. Some of these parasites are also zoonotic, meaning the parasites themselves and/or the diseases they carry are transmissible to humans. Our hospital highly recommends monthly parasite prevention for our patients to protect them, us, and our living environments from these parasites. Our product of choice for dogs is Trifexis, a safe and effective product that controls the flea population by eliminating the adult flea before it has a chance lay eggs. Trifexis also protects against a broad-spectrum of internal parasites including heartworms, roundworms, hookworms, and whipworms. Trifexis is an oral tablet given once per month. For cats we recommend Revolution, a monthly topical treatment that kills adult fleas and protects against heartworms, roundworms, hookworms, and earmites. Birds, reptiles, and small mammals (rabbits, ferrets, chinchillas, rats, etc) each have different needs and product recommendations for parasite control. Please contact our hospital if you have one of these animals and want more information on parasite control and prevention.

EXTERNAL PARASITES

Fleas and Ticks

Both of these parasites take blood meals from your pet and therefore are potential carriers of blood borne diseases.  Ticks can transmit severe illness like Lyme disease, Ehrlichiosis, and Rocky Mountain Spotted Fever.  Fleas cause serious skin reactions and itching in most pets.  They can be the cause of life threatening anemia in puppies, kittens and geriatric pets.  Fleas are also a source of tapeworm infection.

Other external parasites our pets can experience include ear mites, mange mites, lice, fly bots.

INTERNAL PARASITES

Heartworms

These parasites are transmitted in their microscopic youth stage by mosquitoes from pet to pet. When an infected mosquito bites a pet, the immature heartworm gets in the bloodstream and begins to mature. Within 6-7 months the heartworms grow to be 4-6 inches long and begin to plug up the major vessels coming out of the heart. In the dog, heart failure is the main concern. In the cat, sudden death is a possibility. In Oregon, most of the cases of heartworm disease are in the Grants Pass/Medford region. There have also been positive cases reported in Veneta and Eugene. Human cases are rare.  We recommend monthly heartworm preventative for all pets.

Tapeworms

This is the most common worm seen by our clients. This rice grain sized worm can be found on or around the stool, or caught on the hair surrounding your pet’s anus. The real story is that these small “worms” are actually segments from a worm that typically measures 1-2 foot long and lives in your pet’s small intestines. The intermediate hosts are rodents and fleas, therefore pets that hunt or have been exposed to fleas are at greatest risk.  Unlike other intestinal parasites, tapeworm eggs are rarely found during a microscopic exam of the stool.  We often rely on assessment of risk factors, physical exams and owner observation to determine which pets require treatment.

Roundworms

This is the most common internal parasite we diagnose with the fecal exam under the microscope. These worms live in the intestines of cats and dogs.  Their immature stages can form cysts in the muscle tissue and emerge later in a pet’s life. If a pet has a large number of these worms, they will occasionally pass them in the stool. Every female roundworm can lay 100,000 eggs per day. The worms are tubular and 3-6 inches long. Pets may have no symptoms, be unthrifty, experience vomiting and/or diarrhea.  Severe infections in puppies and kittens can result in death. Worms can be passed from the mother through the placenta.  Up to 10,000 cases of human infection from this parasite are reported by the Center for Disease Control in the United States annually. This condition is called Visceral Larval Migrans.  Raccoons carry a roundworm that can infect dogs and humans—please do not feed or encourage them to stay nearby.

Hookworms

This intestinal parasite is one of the most harmful to pets. With sharp mouths, these worms attach to the intestinal lining and take 24 hour a day blood meals from their hosts. We diagnose these worms with fecal exams by identifying their microscopic eggs.  These worms can be passed to the kittens or puppies from their mother’s milk. You will not see these small adult worms in the stool. In humans, this worm can migrate under the skin resulting in Cutaneous Larval Migrans or on rare occasions cause a severe intestinal problem such as eosinophilic enteritis.

Whipworms

This intestinal parasite actually burrows in the intestinal lining and can cause severe disease. The eggs can be found microscopically and identified when examining a fecal sample.  Unlike the heartworm, roundworm, tapeworm and hookworm; it does not seem to affect humans.

Other parasites such as coccidia and giardia are prevalent in our area and in some cases, can pose a serious health risk to your pet.  Proper testing and treatment is available at West Hills Animal Hospital.

RESOURCES

For additional up-to-date information on parasites and your pet please visit www.petsandparasites.org.

Another great website is www.capcvet.org/parasite-prevalence-maps which has an interactive map showing which parasites are most prevalent in the various states.