Physaloptera (Stomach Worm) in Dogs & Cats: 2025 Vet Insights by Dr Duncan Houston 🐶🐱

Hello, I’m Dr Duncan Houston, BVSc. Today let’s explore a less common—but significant—parasite: the stomach worm Physaloptera. Whether you have a vomiting kitty or dog, this guide covers what these parasites are, how they infect, how to diagnose and treat them, and especially how to prevent them with confidence.

1. What Are Physaloptera?

Physaloptera are stout, 3–6 cm nematodes that live in the stomach or small intestine of dogs and cats. They attach themselves using little teeth and feed on tissue and blood—even though infections may appear mild or cause severe vomiting and weight loss in some pets. :contentReference[oaicite:3]{index=3}

2. Where and How Do Pets Get Infected?

• These worms are more common in the **Midwestern U.S.** and outdoor-access pets. :contentReference[oaicite:4]{index=4}
• Definitive hosts like foxes, coyotes, and raccoons shed eggs in feces.
• Eggs are eaten by insects (beetles, cockroaches, crickets)—the intermediate hosts.
• Pets become infected by eating infected insects—or small animals that ate the insects. :contentReference[oaicite:5]{index=5}

3. How Is Physaloptera Different from Other Worms?

• They inhabit the **stomach**, not the intestines like hookworms or roundworms.
• They bite tissue and consume blood, unlike hookworms which only feed on blood. :contentReference[oaicite:6]{index=6}
• Infection occurs in all ages—no puppy or kitten bias.

4. Signs of Infection

The most common sign is chronic or intermittent vomiting. Blood in vomit or dark “tarry” stools (melena) can occur. Some pets show no signs. Even a few worms can cause gastritis. :contentReference[oaicite:7]{index=7}

5. Diagnosing Physaloptera

• Fecal tests are unreliable—eggs are few and heavy, often missed in float tests. Sedimentation or direct smears are more sensitive. :contentReference[oaicite:8]{index=8}
• Vomit inspection: worms or eggs may be visible—photos help your vet. :contentReference[oaicite:9]{index=9}
• Endoscopy allows direct visualization and removal—but worms can hide in mucus or folds, so follow with medication. :contentReference[oaicite:10]{index=10}
• If infection is strongly suspected, vets often start treatment without definitive proof.

6. Treatment & Prognosis

Physaloptera responds well to:
• **Pyrantel pamoate** —20 mg/kg orally every 2 weeks for ≥3 doses. :contentReference[oaicite:11]{index=11}
• **Fenbendazole** —given in higher dose and longer durations, especially for dogs. :contentReference[oaicite:12]{index=12}
• **Ivermectin** is another option in some cases. :contentReference[oaicite:13]{index=13}

Endoscopic removal followed by deworming speeds recovery. Most pets recover well with symptoms resolving within ~2 weeks; ongoing vomiting suggests repeat treatment or alternative diagnosis. :contentReference[oaicite:14]{index=14}

7. Prevention Strategies

• Prevent hunting or eating insects/rodents—keep cats indoors and use fenced/leashed walks for dogs. :contentReference[oaicite:15]{index=15}
• Control insects in your home and outdoor areas.
• Monthly parasite preventatives may reduce risk—though none are guaranteed for Physaloptera. :contentReference[oaicite:16]{index=16}
• Routine stool checks—ask your vet about sedimentation-based testing.

8. Final Takeaways

• Physaloptera isn't common—but consider it when vomiting is unexplained.
• Diagnosis often requires endoscopy or empirical treatment.
• Treatment is straightforward with high success when followed through.
• Prevent by limiting access to insect & rodent hosts and keeping pets indoors or on leash.

📱 Ask A Vet for Questions or Next Steps

Worried about your pet’s vomiting? Not sure about treatment or prevention? Use the Ask A Vet app to connect any time with licensed veterinarians—so you can address stomach worms or other causes, all from home. 🩺📲