Parasites aren’t just pests—they can be a serious threat to your pet’s health. Fleas, ticks, heartworms, and intestinal parasites are more than uncomfortable; they can cause chronic illness, organ damage, and in some cases, even death.

At Heartland Veterinary Hospital in Danville, Kentucky, we believe prevention is the most powerful tool we have. With regular care and year-round protection, most parasitic infections are completely preventable.

Have questions about your pet’s parasite prevention plan?
 Contact Heartland Veterinary Hospital to schedule a wellness visit.

External Parasites: Fleas and Ticks

Fleas: Small Size, Big Problems

Fleas are tiny insects that feed on blood and reproduce rapidly. Once in your home, a single flea can lead to thousands within weeks. In addition to causing intense itching and skin irritation, fleas can transmit tapeworms and cause flea allergy dermatitis (FAD)—a common allergic skin condition in pets.

Signs your pet may have fleas:

  • Scratching, biting, or licking excessively
  • Hair loss, red bumps, or scabs
  • Flea dirt (tiny black specks) visible in the coat or on bedding

Learn more about flea-related allergies from the Merck Veterinary Manual.

Flea prevention tips:

  • Use monthly oral or topical flea preventatives year-round
  • Wash pet bedding and vacuum regularly
  • Treat all animals in the household to break the flea lifecycle

Ticks: More Than Just a Nuisance

Ticks are blood-sucking parasites that attach to your pet’s skin and can transmit dangerous illnesses like Lyme disease, Ehrlichiosis, and Anaplasmosis. They’re most common in wooded areas and tall grass, but they can also show up in suburban yards and parks.

How to spot a tick problem:

  • Check your pet’s skin for attached ticks after outdoor activity
  • Monitor for fatigue, fever, swollen joints, or loss of appetite (signs of tick-borne disease)

Visit the CDC’s guide on preventing ticks on pets to learn more.

Tick prevention and removal:

  • Use prescription tick preventatives—available as chewables, collars, or topical treatments
  • Inspect pets after walks or hikes
  • Remove ticks promptly with fine-tipped tweezers (grasp close to the skin and pull straight out)

Internal Parasites: Heartworms and Intestinal Worms

Heartworms: Silent, Deadly, and Preventable

Heartworm disease is caused by parasitic worms that live in the heart, lungs, and associated blood vessels, leading to severe lung disease, heart failure, and death if left untreated. It is spread through mosquito bites and affects both dogs and, less commonly, cats.

Symptoms of heartworm infection in dogs:

  • Mild: Coughing, fatigue after activity
  • Moderate to severe: Weight loss, difficulty breathing, collapse

Treatment is expensive, time-consuming, and risky. Prevention is far safer and more affordable.

Use the 2024 Canine Heartworm Prevalence Map from CAPC to see local risk levels, and visit the American Heartworm Society for more detailed information.

Heartworm prevention checklist:

  • Administer monthly heartworm preventatives (oral or topical)
  • Schedule annual heartworm testing
  • Avoid missed doses—consistency is critical

Intestinal Parasites: Roundworms, Hookworms, Tapeworms, Giardia & More

Internal parasites affect the gastrointestinal tract and are often picked up from contaminated soil, standing water, feces, or infected prey. Some intestinal parasites can also pose a risk to humans, especially children.

Signs of intestinal parasites:

  • Diarrhea or vomiting
  • Bloated abdomen, weight loss, or poor coat condition
  • Worms visible in feces (e.g., rice-like tapeworm segments)

Explore this helpful guide from the AVMA: Intestinal Parasites in Cats and Dogs.

Prevention and treatment tips:

  • Use monthly preventatives that cover both heartworms and intestinal parasites
  • Schedule routine fecal exams, especially for puppies and kittens
  • Deworm young pets regularly and promptly clean up waste

Parasites Don’t Just Affect Pets: Understanding Zoonotic Risks

Did you know that some parasites can be passed from pets to people? These are known as zoonotic parasites, and they can cause a variety of health issues in humans—especially children, older adults, and individuals with weakened immune systems.

Common Zoonotic Parasites Include:

  • Roundworms (Toxocara spp.)
    These intestinal worms can be transmitted to humans through contact with contaminated soil or pet feces. In rare cases, they can cause a serious condition called visceral or ocular larva migrans, which may lead to organ or eye damage.
  • Hookworms
    These parasites can penetrate human skin—often through bare feet on contaminated ground—causing cutaneous larva migrans, a painful, itchy skin condition.
  • Giardia and Cryptosporidium
    These microscopic parasites cause diarrheal illness in both pets and people. Infected pets can shed the parasites in their feces, contaminating shared environments or water sources.
  • Tapeworms (Dipylidium caninum)
    Children are most at risk, especially if they accidentally swallow a flea carrying tapeworm larvae.

For more information on intestinal parasites and how they affect both pets and humans, check out the AVMA’s guide on Intestinal Parasites in Cats and Dogs.

How to Protect Your Family:

  • Practice good hygiene: Always wash hands after cleaning up pet waste, gardening, or playing outside.
  • Scoop the poop: Promptly clean up after your pet—especially in yards and shared outdoor spaces.
  • Keep pets on year-round parasite prevention: Many preventatives protect against both heartworms and intestinal parasites.
  • Deworm young pets regularly: Puppies and kittens are more likely to carry parasites and shed eggs into the environment.
  • Avoid allowing pets to drink from shared water sources, like ponds, puddles, or communal bowls at dog parks.

Zoonotic parasites are a real risk—but they’re also highly preventable. By protecting your pets, you’re also protecting your family.

Why Year-Round Parasite Prevention Matters

Many people think parasites are only a problem in spring and summer—but that’s not true. Fleas can survive indoors year-round, and heartworm-carrying mosquitoes have been documented in every U.S. state, even during milder winters.

Preventing parasites year-round isn’t just a recommendation—it’s essential.

Read more from AAHA on The Importance of Year-Round Parasite Prevention.

Four ways to keep your pet protected:

  1. Use year-round preventatives recommended by your veterinarian
  2. Check your pet’s coat regularly for signs of fleas and ticks
  3. Schedule annual wellness exams and fecal testing
  4. Maintain a clean environment (pick up waste, limit standing water, and mow tall grass)

When to See a Veterinarian

If you notice any of the following symptoms, contact your veterinarian immediately:

  • Persistent itching or hair loss
  • Diarrhea, vomiting, or visible worms
  • Fatigue, coughing, or difficulty breathing
  • Red, inflamed skin or flea dirt
  • Ticks attached to your pet

Parasites often go unnoticed until symptoms appear. Routine checkups and preventative care are the best way to catch problems early—or avoid them entirely.

Concerned about parasites?
 Schedule an appointment with Heartland Veterinary Hospital for a customized prevention plan.

Prevention Is Protection

Parasite prevention should be a non-negotiable part of your pet’s year-round health plan. From itchy flea infestations to life-threatening heartworm disease, parasites can cause major harm—but with consistent care, they’re almost entirely preventable.

At Heartland Veterinary Hospital, we’re here to help you choose the right products, stay on schedule, and keep your pets parasite-free.

Visit us or contact us here to get started with a prevention plan tailored to your dog or cat.