Complete Guide to Pet Parasites

Parasites are more than just annoying — they can cause serious disease, transmit other pathogens, and in some cases (like <a href="/conditions/canine-heartworm">heartworm</a>) be fatal.

Fleas

The most common external parasite. Fleas cause itching, allergic dermatitis, and can transmit tapeworms. A single female flea can lay 50 eggs per day — an infestation explodes exponentially.

Signs: Scratching, chewing, hair loss (especially lower back/tail base), flea dirt (black specks that turn red when wet).

Treatment: Veterinary-prescribed oral (isoxazolines: Bravecto, Simparica, Credelio) or topical preventives. These are highly effective and safe. OTC products are less reliable.

Environmental control: Vacuum thoroughly (dispose of the bag), wash bedding in hot water. 95% of fleas are in the environment (eggs, larvae, pupae), not on the pet.

Ticks

Ticks transmit serious diseases: Lyme disease, Ehrlichiosis, Anaplasmosis, Rocky Mountain spotted fever, and Babesiosis.

Tick removal: Use fine-tipped tweezers, grasp close to the skin, pull straight up with steady pressure. Do NOT twist, burn, or apply substances — these cause the tick to regurgitate into the bite.

Prevention: Same oral/topical preventives that cover fleas usually cover ticks. Check your pet for ticks daily if you live in an endemic area.

Intestinal Worms

Roundworms

Nearly all puppies and kittens are born with roundworms. They look like spaghetti in feces or vomit. Can be transmitted to humans (visceral larva migrans).

Hookworms

Blood-feeding worms that attach to the intestinal lining. Can cause severe anemia, especially in puppies. The larvae can penetrate human skin (cutaneous larva migrans).

Whipworms

More common in dogs. Cause chronic large bowel diarrhea. Eggs survive in soil for years.

Tapeworms

Segments look like rice grains around the pet's anus or in feces. Transmitted by fleas or by eating infected prey. Most routine dewormers don't cover the most common tapeworm (Dipylidium) — praziquantel is needed.

<a href="/conditions/canine-giardiasis">giardia</a>

A protozoan parasite causing chronic soft/mucous diarrhea. Common in puppies, kennels, and dog parks. Diagnosed by fecal testing. Treat with fenbendazole ± metronidazole. Zoonotic potential.

<a href="/conditions/canine-heartworm">heartworm</a>

The most dangerous parasite. Transmitted by mosquitoes. Adult worms live in the heart and pulmonary arteries. Treatment is expensive, risky, and painful. Prevention is cheap, safe, and easy. YEAR-ROUND PREVENTION FOR ALL DOGS AND CATS.

Prevention Is Everything

Year-round broad-spectrum parasite prevention for all pets, year-round, regardless of lifestyle. The cost of prevention is a fraction of the cost of treating the diseases parasites cause.