Feline Lungworm (Aelurostrongylosis)
Aelurostrongylus abstrusus is a small worm that lives in the cat's lungs. Cats become infected by eating snails or slugs, or small prey that have eaten them—rodents, lizards, birds, and frogs. Many infected cats show no signs at all. In oth...
What is it?
Aelurostrongylus abstrusus is a small worm that lives in the cat's lungs. Cats become infected by eating snails or slugs, or small prey that have eaten them—rodents, lizards, birds, and frogs. Many infected cats show no signs at all. In others, the worm causes coughing and breathing difficulty that closely resemble asthma. This parasite is widespread throughout Europe, including the Mediterranean region; its precise frequency in Tunisia is not well documented.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Often, no visible signs. Coughing, sometimes persistent, with no fever. Rapid, difficult breathing, sometimes with mouth open in heavy infestations. Wheezing when breathing, especially during coughing fits. Sneezing and nasal discharge. Lethargy, decreased appetite, weight loss. Signs often develop gradually over weeks: a persistent cough in a cat that goes outdoors and hunts should raise suspicion of this worm.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Infestation is caused by the worm Aelurostrongylus abstrusus. Adult worms live in the lungs and lay eggs; larvae are coughed up, swallowed, then passed in the faeces. In the environment, they penetrate snails and slugs, where they develop. Cats become infected by eating these snails or slugs, or small animals that have eaten them.
Outdoor cats that hunt: rodents, lizards, birds, and frogs.
Cats that eat snails or slugs.
Stray or free-roaming cats.
Living in an area where the parasite is present, such as the Mediterranean region.
An indoor-only cat with no access to prey has very low risk.
Transmission
There is no direct transmission from one cat to another. The cycle necessarily involves snails or slugs: the cat becomes infected by eating them, or by eating small prey that have consumed them. The worm is not transmitted to humans.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
Your veterinarian listens to your cat's lungs and asks about the cat's lifestyle: does it go outside, does it hunt?
Diagnosis mainly relies on finding larvae in fresh feces using a specific test method. Because larvae are shed irregularly, the test may be repeated over several days.
Testing for the parasite's genetic material may also be done.
Chest X-rays show lesions, but they resemble those of asthma.
Before concluding that asthma is the problem, your veterinarian checks for this worm, since the two diseases are similar and treated differently.
Treatment
Treatment consists of an antiparasitic drug active against this worm, prescribed by your veterinarian.
Additional treatment may be given to reduce inflammation in the bronchi or improve breathing in severe cases.
A fecal test after treatment confirms that the parasite has been eliminated.
Not all wormers are effective against this worm: only your veterinarian can choose the right product.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
For a cat that goes outdoors and hunts, regular antiparasitic treatment suited to the level of risk and given according to a schedule set by your veterinarian is recommended.
Limit hunting and access to snails and slugs if possible.
Clear feces from the garden and litter box regularly.
Possible complications
Significant breathing difficulty in heavy infestations, especially in kittens and elderly cats.
Secondary lung infection.
Lasting lung damage in chronic infestations.
When to see a veterinarian
Your cat breathes with its mouth open, or its gums or tongue are blue: seek urgent care.
It has been coughing for several days, especially if it goes outside and hunts.
Its breathing is rapid or difficult while at rest.
It wheezes when breathing.
It tires easily, eats less, or is losing weight.
Prognosis
The prognosis is good for most treated cats.
It is more guarded in cases of heavy infestation, especially in kittens, elderly cats, or weakened cats.
Frequently asked questions
How to distinguish it from asthma?
The signs are very similar: cough, wheezing, breathing difficulty. Lifestyle helps: a cat that goes outside, hunts, and eats snails is exposed to the worm, whereas a strictly indoor cat is exposed to it very little. Only fecal analysis can settle the matter, and it must be done before concluding it is asthma.
My cat has been coughing for weeks without fever: could it be pneumonia?
Pneumonia is generally accompanied by fever, marked lethargy, and a more rapid course. A cough lasting without fever in a hunting cat suggests pulmonary worms or asthma more likely.
Can my indoor cat get this worm?
It is very unlikely, because cats become infected by eating snails, slugs, or small prey. In a strictly indoor cat that coughs, the veterinarian will first consider other causes.
Can I catch this worm?
No. Aelurostrongylus abstrusus is not transmitted to humans, nor directly from one cat to another.
References
ESCCAP — European Scientific Counsel Companion Animal Parasites
Content reviewed by the TunisieVet editorial team · Updated 10 October 2026
Comments (0)
No comments yet.
AT A GLANCE
Need a veterinarian?
Find a practitioner near you on TunisieVet, with their specialities, hours and contact details.
Find a veterinarianCategories
Affected species
This information is provided for educational purposes only and is not a substitute for a veterinary consultation. If you have any concerns about your animal's health, consult a veterinarian.
Thinking of welcoming a pet? Dogs and cats are waiting for a family in Tunisia, and adoption is completely free.
Adoption listingsOn the TunisieVet marketplace
Food, hygiene and accessories for cat, sold by verified shops and delivered across Tunisia.
Buying advice, not medical advice: for a diagnosis or treatment, consult your veterinarian.
To discover
Related diseases and linked Animalia content.
Rabies
Viral · Vaccine available
Hip dysplasia
Other
Otitis externa
Environmental
Periodontal disease
Other
