Overview:

Lungworms are parasitic nematodes. There are two lungworms of the cat Capillaria aerophila & Aelurostrongylus abstrusus.

How do cats become infected with lungworms?

Capillaria aerophila has a direct life cycle & may be transmitted via earthworms & rodents. Cats become infected by ingestion of food or water infected with larvae.

Cats become infected with Aelurostrongylus abstrusus by ingesting intermediate hosts (an intermediate host is an organism inside which a parasite does not sexually reproduce. It may grow or reproduce asexually, but there is no exchange of genetic material between individuals), such as snails or paratenic (paratenic describes an intermediate host which is not needed for the development of the parasite, but nonetheless serves to maintain the life cycle of the parasite) [1] hosts (birds, rodents etc).

After ingestion, the larvae pass into the intestine. The larvae penetrate intestine wall and migrate to the lungs in the blood, once they have matured to adult worms (approx 40 days) they lay eggs, these hatch into microscopic larvae which are coughed up, swallowed & passed in the feces.

What are the symptoms of lungworms in cats?

Cats are commonly asymptomatic to lungworm, but some symptoms they may display include;

• Coughing
• Dyspnea (shortness of breath)

Complications may include interstitial emphysema [2], pulmonary edema & secondary bacterial pneumonia.

How are lungworms diagnosed?

Your veterinarian will perform a physical examination of your cat & obtain a history from you. Lungworm is diagnosed by finding first stage larvae in the feces. Other tests your veterinarian may wish to perform include;

• X-rays
• Tracheal wash

How are lungworms treated?

Your veterinarian will recommend a worming medication to eradicate the parasites.

References:

[1] Wikipedia

[2] Merck Veterinary Manual