How to Care for a Healthy Cat: LUNGWORMS

The Classic Comprehensive Handbook of Cat Care: LUNGWORMS

Lungworms, as their name implies, are small (about one-fourth-inch, 0.6 cm long) roundworms who as adults live in the lungs of cats. The more common lungworm, Aelurostrongylus abstrusus, infects cats who have eaten snails, slugs, rodents, frogs, lizards, or birds carrying infective larvae of the worm.

These intermediate and transfer hosts become infected when they ingest larvae that have been coughed up and then swallowed and passed in the stool of affected cats. Although infection is uncommon, lungworms do occur in many areas all over the United States and Europe, so an informed cat owner should be aware of their occurrence.


The first sign of lungworm infection is usually a persistant cough, often accompanied by a gradual weight loss. Other signs in addition to cough can be fever, loss of appetite, nasal discharge, and sneezing. Therefore, it is easy to confuse this disease with other causes of respiratory distress.


Diagnosis and treatment of lungworm disease may be difficult and must be done by a veterinarian. Veterinarians look for lungworm larvae (or eggs, in certain cases) in the stool (or sputum) of infected cats, so it can be helpful to bring a stool sample when you take your cat to be examined.

There are few effective drug treatments; they include ivermectin and fenbendazole. Prevent infection with the common lungworm by restricting your cat from hunting.