Roundworms in Cats and Kittens 🐱🪱

By Dr Duncan Houston, BVSc

Roundworms are among the most common intestinal parasites found in cats—especially kittens. These worms are easy to treat but can cause serious health issues if ignored. In this 2025 guide, Dr Duncan Houston explains how cats get infected, what symptoms to watch for, and how to protect your home and family. 💩

🔬 Two Types of Roundworms in Cats

• 🐱 Toxocara cati – affects cats only; more harmful
• 🐶 Toxascaris leonina – affects both dogs and cats

While both are treatable with the same medications, Toxocara cati poses a greater risk to kittens and is also a concern for human health. 🧬

🧪 How Do Cats Get Roundworms?

There are three main infection routes for Toxocara cati:

• 🌱 Ingesting eggs from contaminated soil or feces
• 🍼 Nursing from an infected mother cat
• 🐭 Eating infected rodents (transport hosts)

Fresh feces are not infectious—eggs must incubate in soil for 2–4 weeks before becoming contagious. 🧼

⚠️ Why Roundworms Are Dangerous

Heavy infestations can cause:

• 🤮 Vomiting (sometimes with visible worms)
• 💩 Diarrhea
• 🍼 Pot-bellied appearance in kittens
• 📉 Poor weight gain or growth
• 🫁 Pneumonia if larvae migrate through the lungs
• 🚫 Intestinal blockage (severe cases)

Human infection is possible (especially in children) through contact with contaminated soil. 🧍‍♂️🧒

🧬 Life Cycle of Toxocara cati

1. Eggs are passed in feces and incubate in soil for 2–4 weeks
2. Cat ingests eggs or infected prey
3. Larvae migrate through the liver and lungs
4. Larvae are coughed up and swallowed
5. Back in the intestines, larvae mature and lay eggs

This cycle takes about 4–5 weeks. Nursing kittens get infected via milk, and the mother's deworming does not prevent this. 🔄

🧫 How to Diagnose Roundworms

• 💩 Fecal float test (looks for eggs)
• 👀 Visual confirmation (vomiting a worm)
• 🔍 Regular screening during kitten exams

Roundworms look like spaghetti—white, round, and several inches long. Bring samples to your vet if unsure. 🧪

💊 Deworming & Treatment Options

Common active ingredients:

• 💊 Pyrantel pamoate (Strongid®, Drontal®, Heartgard Plus®)
• 💊 Piperazine (many OTC products)
• 💊 Fenbendazole (Panacur®)
• 💉 Selamectin (Revolution®)
• 🧴 Emodepside (Profender®)
• 🧴 Moxidectin (Advantage Multi®)
• 💊 Milbemycin oxime (Interceptor®)

Important:

• ⚠️ Most dewormers kill only adult worms
• 🗓️ Follow-up treatments are needed every 2–3 weeks to target migrating larvae
• 🧬 Some newer products kill immature worms—but not all

🍼 Recommended Kitten Deworming Schedule

• 🐾 Start at 2 weeks old
• 💊 Repeat every 2–3 weeks until 8–12 weeks
• 🩺 Then start monthly parasite prevention

The Companion Animal Parasite Council (CAPC) recommends monthly heartworm preventives with deworming coverage for life. 🐈

🧼 Environmental Prevention

• 💩 Scoop litterboxes daily—fresh feces is not infectious
• 🧺 Wash bedding regularly
• 🚫 Don’t let cats hunt
• 🧽 Disinfect sandboxes and keep them covered

👨‍👩‍👧‍👦 What About Human Infection?

Humans can be infected through contact with soil contaminated by cat feces. Toxocariasis may affect the eyes, brain, or liver—especially in children. 👁️🧠

Handwashing and litter hygiene are critical. Teach children not to play in uncovered sandboxes. 🧼

📱 Ask A Vet App Support

Need help identifying worms or staying on schedule with deworming? The Ask A Vet app offers:

• 📸 Submit photos of worms or symptoms
• 💬 Chat with licensed vets about treatments
• 📅 Track follow-up deworming dates
• 🧪 Upload fecal test results for review

🏁 Final Takeaway

Roundworms are common—but easy to treat and prevent. With routine deworming, parasite-safe litter habits, and the right products, your cat can stay healthy—and your home worm-free. 🐱🪱❤️