At Bull City Veterinary Hospital in Central Durham, parasite prevention is one of the most important things we discuss with pet parents. From flea infestations to intestinal worms, parasites can cause everything from mild irritation to life-threatening conditions in dogs and cats. The good news? Most are completely preventable with the right care.

In this guide from a Central Durham veterinarian, you’ll learn about the common parasites in dogs and cats, how they spread, what symptoms to watch for, and our best flea and tick prevention tips to keep your furry family members healthy year-round.

Common Parasites in Dogs and Cats

Parasites fall into two main categories:

External Parasites:

• Fleas
  
• Ticks
  
• Mites (like ear mites or mange)
  

Internal Parasites:

• Roundworms
  
• Hookworms
  
• Tapeworms
  
• Whipworms
  
• Heartworms
  
• Giardia and coccidia (protozoa)
  

Each one affects pets differently, so understanding the risks is the first step to protection. Heartworms are particularly dangerous, and can be deadly. Click to learn more about heartworms and associated symptoms at the American Heartworm Society here.

Fleas: Small Pests, Big Problems

Fleas are tiny, wingless insects that survive by feeding on blood. Once they infest your home or pet, they can multiply rapidly—laying hundreds of eggs that fall into carpets, bedding, and furniture.

Signs of Fleas:

• Scratching, biting, or licking the skin
  
• Hair loss (especially around the base of the tail)
  
• Flea dirt (black specks that turn red when wet)
  
• Tapeworms in stool (transmitted via flea ingestion)
  
• Anemia in puppies, kittens, or small pets
  

Fleas also spread diseases like Bartonella (“cat scratch fever”) and can trigger serious allergic reactions. You can read some not-so-fun facts about fleas at the PetMD website here.

Ticks: Disease-Carrying Hitchhikers

Ticks latch onto pets (and people) during walks through tall grass, woods, or brush. Once attached, they feed for hours or days, potentially transmitting:

• Lyme disease
  
• Ehrlichiosis
  
• Anaplasmosis
  
• Rocky Mountain spotted fever
  

Tick Warning Signs:

• Visible tick on skin (especially ears, neck, or between toes)
  
• Fever
  
• Lethargy
  
• Joint pain or lameness
  
• Loss of appetite
  

Removing ticks promptly and using preventive medications year-round is essential.

Worms: A Hidden Health Hazard

Roundworms

Extremely common—especially in puppies and kittens. Transmitted through the environment or from mother to offspring.

Symptoms:

• Potbellied appearance
  
• Vomiting or diarrhea
  
• Visible worms in stool or vomit
  

Hookworms

These tiny worms attach to the intestinal wall and feed on blood. They can cause:

• Bloody stools
  
• Weight loss
  
• Pale gums
  
• Lethargy
  Hookworms are zoonotic, meaning they can infect humans through skin contact.
  

Tapeworms

Usually transmitted by swallowing infected fleas. These flat, segmented worms often cause:

• Scooting
  
• Visible “rice grain” segments near the tail
  
• Weight loss despite a normal appetite
  

Whipworms

Less common but very harmful. They live in the large intestine and cause:

• Chronic diarrhea
  
• Weight loss
  
• Dehydration
  

Heartworms

Transmitted by mosquito bites, these worms live in the heart and lungs. They’re dangerous—and potentially deadly.

Symptoms (often in later stages):

• Coughing
  
• Fatigue
  
• Difficulty breathing
  
• Collapse
  

Heartworm prevention is critical, especially in warmer regions and during mosquito season.

Signs of Worms in Pets

While some infestations are visible, many internal parasites go unnoticed without a stool test. Keep an eye out for:

• Diarrhea (with or without blood)
  
• Vomiting
  
• Weight loss
  
• Scooting or licking the rear
  
• Visible worms or segments in stool
  
• Pale gums or pot-bellied appearance
  

If you see any of these signs of worms in pets, call our vet clinic immediately for a diagnostic screening.

Flea and Tick Prevention Tips

Prevention is the best medicine. At Bull City Veterinary Hospital in Central Durham, we recommend year-round protection with:

• Topical or oral monthly preventives
  
• Combination products that protect against fleas, ticks, and heartworm
  
• Tick checks after outdoor activities
  
• Regular bathing and grooming
  
• Keeping your yard mowed and clear of debris
  

Never use dog flea products on cats—they can be toxic. Let us recommend the right formula for your pet’s species, age, and weight.

Deworming Guidelines

We follow the latest AAHA and CAPC guidelines for deworming:

• Puppies and kittens: Start at 2–3 weeks of age, then repeat every 2 weeks until 12 weeks
  
• Adult pets: At least 1–2 times per year, or more if at risk
  
• Pets who hunt, go outdoors, or live with children may need more frequent treatment
  

Fecal testing during routine wellness visits helps us catch parasite problems early.

Indoor Pets Need Parasite Prevention Too

Even indoor pets aren’t immune. Fleas and mosquitoes can enter your home through windows, clothing, or other pets. And since indoor cats often don’t show symptoms until problems are advanced, prevention is even more important.

We recommend monthly preventives for all pets—indoors or out.

FAQs About Parasite Prevention

Can I buy parasite preventives over the counter?

Some products are available without a prescription, but not all are safe or effective. We recommend vet-approved brands tailored to your pet.

Are parasite preventives safe?

Yes, when used as directed. We’ll help you choose the best product for your pet’s age, weight, and medical history.

My pet had worms once. Do I still need monthly prevention?

Yes. Treating worms once doesn’t provide future protection. Ongoing prevention is key. Read more about seasonal pet care at our blog here.

Complete Parasite Protection Starts Here in Central Durham

At Bull City Veterinary Hospital in Central Durham, we take parasite prevention seriously—because your pet’s health depends on it. Whether it’s protecting against common parasites in dogs and cats, choosing the right flea and tick prevention tips, or spotting early signs of worms in pets, our team is here to help. You can learn more about our animal clinic and services offered at our Services page here.

Schedule your pet’s parasite screening or prevention consult today and keep the creepy crawlies far away.

This blog is for informational purposes only. Always consult your veterinarian for medical advice and treatment.