Note for Pet Owners:
This information is provided by
Provet for educational purposes only.
You should seek the advice of
your veterinarian if your pet is ill as only he or she can correctly advise
on the diagnosis and recommend the treatment that is most appropriate for
Topics on this Page:
As the name of the disease implies, feline lungworm is caused by parasitic worms
which live in the lungs of infected cats.
Causeere are several helminth worms which have been reported to cause lungworm
disease in cats :
- Aelurostrongylus abstrusus (the most common cause)
- Filaroides trostratus
- Osleroides massinoi
- Troglostrongylus brevior
- Troglostrongylus subcrenatus
In the case of Aelurostrongylus abstrusus adult worms lay their eggs in the
small airways of the lungs (the bronchioles and alveolar ducts). When the eggs
hatch the larvae that emerge damage lung tissue before they are coughed up,
swallowed and passed out in the cat's faeces. Once in the environment
the larvae need to be eaten by another host (eg birds, molluscs or rodents)
which is called an intermediate host. Cats then get re-infected when they eat
their prey and the larvae migrate from the gastrointestinal tract to the lungs
where they develop into adults , and the lifecycle of the worm begins again.
There are no specific breed predispositions to developing this disease, however
cats that hunt birds, slugs or snails and rodents are most at risk to contract
the parasite, as these can be intermediate hosts for the larval stage of the
Many cats that have lungworms present show no signs at all. When signs do
occur the cat usually has a large number of worms present, and they
- Difficulty breathing (called dyspnoea)
ComplicationsDamage to the lungs and airways can lead to secondary infections and
The diagnosis is confirmed by identifying early stage larvae of the worm
in the faeces of infected cats. The faeces is examined using the Baermann
technique, however eggs are not shed all the time, and so repeated testing is
often needed before they are found.
Several drugs have been used to treat lungworm in cats including :
Many infected cats do not show any signs of disease and the condition is
self-limiting , the cat naturally eliminating it's worm burden in 3-4 months.
The prognosis is good for most treated cats with heavy parasite burdens, unless
severe secondary pneumonia develops.
Updated October 2013