Lungworm In Cats (Vet Advice)

The facts and information in this article have been checked and approved by small animal veterinarian Dr. Abdul Basit Javed (DVM, RVMP).

Lungworm in cats is a respiratory infection that has recently become more prevalent.

As a cat owner, you must have a basic understanding of this illness because it can cause multiple complications in cats if not diagnosed and treated early.

Cats can suffer from a variety of respiratory infections, some of which are caused by parasites. Parasitic respiratory infections can be difficult to diagnose because their symptoms usually overlap with other respiratory diseases. If left untreated, parasitic respiratory infections can cause severe respiratory distress and even death in cats.

If you own a cat and are concerned that your cat has a lungworm infection, we are here to help.

The post covers the symptoms, diagnosis, treatment, and much more about lungworm in cats, so continue reading.

Lungworm In Cats

Parasitic respiratory infections are fairly common in cats all over the world and can be fatal.

One such parasitic respiratory infection in cats is lungworm.

In cats, several nematode species (roundworms) cause lungworm infection.

Lungworms generally affect cats’ lower respiratory tract, which includes the trachea (windpipe), bronchi, bronchioles, and air sacs known as alveoli.

Different lungworm species can infect different parts of the cat’s respiratory tract.

For example, Aelurostrongylus abstrusus infects the bronchioles, air sacs (alveoli), and alveolar ducts, whereas Eucoleus aerophilous infects the windpipe (trachea).

Types Of Lungworm

One thing to keep in mind about lungworms is that they can refer to a variety of respiratory parasites, not just one species of parasite.

For example, the most common and well-known lungworm in domesticated cat populations worldwide is feline lungworm.

Scientifically known as Aelurostrongylus abstrusus (Strongylida, Angiostrongylidae).

Eucoleus Aerophilous is another lungworm that affects cats and is also known as:

  • Capillaria aerophila and Paragonimus species
  • Oslerus rostratus
  • Troglostrongylus brevior

Symptoms Of Lungworm In Cats

In cats, lungworm infection can range from asymptomatic (no symptoms) to mild or severe.

Symptoms of lungworm in cats are generally associated with the respiratory tract and depend on the cat’s age and overall health, as well as the species of the parasite.

If you are wondering how to diagnose lungworm in cats, start by assessing the symptoms being exhibited by your cat.

We can divide the lungworm in cats symptoms into two types:

  • Respiratory Symptoms
  • Generalized Symptoms

Respiratory Symptoms

The symptoms of lungworm in cats associated with the respiratory system are as follows:


Dyspnea is a common symptom of lungworm infection in cats. It is defined as shortness of breath or difficulty breathing.

Dyspnea occurs due to the presence of fluid within the alveoli of the lungs and due to the constriction and inflammation of the airways.


Tachypnea is described as an increase in respiratory rate.

When the cat is unable to breathe properly due to the presence of worms in the lungs, tissue damage, and other complications, the respiratory rate of the cat increases so that more oxygen can be supplied to the body.

Respiratory Sounds

The following are some of the most common respiratory sounds associated with lungworm in cats:

1. Wheezing

Wheezing is a high-pitched sound similar to whistling which is a common respiratory noise in cats with lungworm infection.

Wheezing is usually caused by the narrowing of the bronchioles due to bronchitis.

Wheezes can sometimes be heard without a stethoscope.

2. Crackles (End-Inspiratory Crackles)

Crackles, particularly end-inspiratory crackles or crepitant crackles, can be heard in lungworm-infected cats.

The crackling sound, which is similar to the popping sound of the bubble wrap, is caused by the collapse of the alveoli and the presence of fluid in the cat’s lungs.

It is usually only audible with the help of a stethoscope.


Cat lungworm cough is a classic symptom of lungworm infection in felines.

Coughing is the body’s response when something obstructs airflow.

In the case of lungworm, inflammation of the bronchi and bronchioles narrows the airways, obstructing airflow.

Worms can also block airways, particularly in kittens due to the small diameter of their airways.

The cough can also occur due to fluid accumulation in the lungs as a result of pneumonia.

Depending on the parasite, coughing can be productive or dry.

Capillaria aerophila infection typically causes dry coughing, whereas other lungworms that cause pneumonia cause productive coughing.

Open Mouth Breathing

Due to the accumulation of fluid and discharge, cats with lungworm infections are unable to breathe through their nostrils.

In order to compensate for the increased oxygen demand in the body, the cat will breathe through its mouth, which is basically open-mouth breathing or labored breathing.

Abdominal Breathing

When cats breathe normally, only their thoracic muscles and diaphragm are involved in the process of respiration.

However, when they have difficulty breathing, such as with a lungworm infection, you will notice your cat’s entire abdomen expanding and relaxing as the cat breathes.

Abdominal breathing is usually not a good sign because it has a negative impact on your cat’s overall health.

Learn more about Maine Coon panting, here.


Bronchitis is the inflammation of the bronchi and bronchioles, which is common in almost every cat with lungworm.

It is also the reason why cats make wheezing sounds.

Some of the worms can embed themselves in the bronchial tissue, causing cysts to form.

One species of these respiratory parasites, the Capillaria aerophila causes chronic (long-term) bronchitis in cats.


Tracheitis is an inflammation of the trachea that is a fairly common symptom in many cats with lungworm.

Eucoleus aerophilous primarily infects the trachea (windpipe) of cats, resulting in tracheitis.


Pneumonia is defined as the inflammation of the lungs’ air sacs or alveoli, which are also the main functional tissue of the lungs because gaseous exchange occurs through these alveoli.

Lungworm infection can cause bronchopneumonia, a type of pneumonia in which the air sacs become inflamed and the cat fails to breathe normally.

Pneumonia is common in cats who are already ill and have a compromised immune system or are very weak.

All of the air sacs become narrow due to inflammation, resulting in less surface area for gaseous exchange.

Pleural effusions (fluid accumulation between the layers of the pleural membrane outside the lungs) and pneumothorax (air accumulation outside the lung but within the pleural membrane) can worsen the severity of pneumonia in cats.

Fluid can also accumulate in the air sacs of the lungs as a result of pneumonia.

Parasitic pneumonia can also occur in combination with bacterial or viral respiratory infections.

Formation Of Sub-Pleural Nodules On The Cat’s Lungs

The formation of nodules on the lung beneath the pleural membrane is one symptom that is usually not visible from the outside (the membrane that surrounds the lungs).

To prevent the spread of worms, the cat’s body sends macrophages, a type of white blood cell (WBC), to the lungs.

These macrophages surround the eggs and worms, forming a granuloma, or in simple words a nodule.

These can then be seen in the tissue and surface of the lungs of the infected cat using radiography.

Nasal Discharge

Nasal discharge is a fairly common symptom of lungworm in most cats.

Initially, nasal discharge may be watery and clear, but as the parasitic infection progresses, it may become mucopurulent.

In simple words you will see a thick mucus discharge sometimes containing pus which can be whitish or yellowish or a mix of both.

Mucopurulent discharge can also indicate that your cat is suffering from a bacterial infection.

Here are some other Maine Coon nasal issues, that your cat may suffer from, which are not connected to lungworm in cats.

Right Side Cardiomegaly

This symptom mostly occurs in kittens and is a rare symptom, the right side of a kitten’s heart can enlarge.

As the respiratory parasites cause pneumonia, disrupting the kitten’s normal airflow and breathing, blood pressure increases, especially in the arteries of the lungs and the right side of the heart (pulmonary hypertension).

Cardiomegaly of the right side of the heart is caused by changes in blood pressure.

Generalized Symptoms Of Lungworm

The following are some of the generalized symptoms caused by lungworm infection in cats:

1. Increased Heart Rate

Tachycardia, or rapid heartbeat, is caused by a lack of oxygen in the body as a result of poor respiration.

The heart starts to beat rapidly in order to compensate for the lack of oxygen in the cat’s body.

2. Apathy

Apathy is defined as a lack of interest in one’s surroundings and activities.

Cats with lungworm infection prefer to lie down, show no interest in playing, and may stop grooming themselves.

3. Lethargy

The cat’s energy levels drop and they become less active, which is usually caused by poor breathing.

4. Depression

In the case of lungworm infection, your cat may exhibit behavioral changes such as depression and anxiety, but these symptoms will be accompanied by respiratory symptoms.

5. Anorexia

The majority of cats will lose their appetites, and some may completely stop eating.

This can result in:

  • Weight Loss
  • Emaciation
  • Dehydration
  • Further degrading health

6. Fever

Every time a cat gets sick with an infection, it will also get a fever, though the severity of the fever will depend on how bad the infection is.

7. Lymph Node Enlargement

Some lymph nodes in cats can become enlarged as a result of lungworm infections, and you may notice bumps on its body when petting it.

8. Anemia

Some cats can develop anemia as a result of lungworm infection, and these cats usually have pale gums and eye membranes (source 1,2,3).

Is Lungworm Fatal In Cats?

Lungworms can infect cats of any age and, if not treated properly, can be fatal, especially in kittens and senior cats.

Lungworms can also cause mixed infections. This means that multiple species of these respiratory nematodes can cause the infection at the same time, making the infection more severe and difficult to treat.

Lungworm infection in cats can be asymptomatic (without symptoms), this usually happens if the cat has good overall health and strong immunity.

Lungworm infections can be mild or severe, depending on the cat’s health and the species of lungworm.

Lungworm infections can sometimes occur simultaneously with viral and bacterial respiratory infections.

In such cases, the severity of the disease intensifies, and such complications are difficult to treat. If the cat is a kitten or a senior cat, the chances of survival and recovery are also low.

As a result, it is crucial to never overlook any respiratory signs displayed by your cat, even if it is a mild cough, and have your cat examined by a veterinarian to rule out the possibility of serious illnesses.

How To Treat Lungworm In Cats

Lungworm in cats treatment can generally be divided into two types:

  • Specific treatment to eliminate the eggs, larvae, and worms from the cat’s body.
  • Supportive treatment to help the cat recover quickly and return to good health.

Let’s look at these in greater detail:

Specific Treatment

Specific treatment usually involves administering anti-parasitic drugs to the cat to eliminate worms as well as their larvae.

Fortunately, if there are no serious complications, lungworm can be successfully treated in cats with antiparasitic drugs.

Anti-parasitic drugs are usually administered for two months to ensure that all parasites are removed from the cat’s body.

The following are some of the most commonly prescribed anti-parasitic drugs for treating lungworms in cats:

  • Fenbendazole
  • Albendazole
  • Ivermectin
  • Praziquantel
  • Levamisole
  • Selamectin
  • Emodepside

Lungworm infection can sometimes occur in conjunction with bacterial infections, such as pneumonia.

In such cases, antibiotics will be given to the cat as a specific treatment to eliminate bacterial infections, as well as painkillers to relieve pain.

Depending on the cat’s condition, anti-inflammatories such as corticosteroids may also be administered to reduce inflammation in the respiratory tract.

Supportive Treatment

Cats are given supportive therapy to help them recover from the damage caused by respiratory parasites.

Depending on the cat’s health, this treatment may or may not be given to it; if the cat’s health is good, supportive therapy is usually not given.

Supportive therapy for lungworm infection in cats consists of the following (source 1,2,3):

  • IV therapy (to supply your cat with fluids, electrolytes, and vitamins) 
  • Oxygen therapy (to improve the oxygen concentration in the body of your cat)

How Do Cats Catch Lungworm?

Cats become infected with lungworms when they consume the worms’ eggs or larvae.

When the eggs are ingested, they hatch in the cat’s intestinal tract and the larvae migrate through the bloodstream from the intestines to the lungs.

After reaching the desired location in the lungs, the larvae will begin to mature into adults, after which some will lay their eggs and others will begin to shed from the cat’s body, usually in the stool (source 1,2,3,4,5).

How Do Cats Get Lungworms?

Different lungworm species have different routes of transmission but a cat can become infected with lungworm in three ways:

Indirect Transmission

  • A cat can become infected with lungworm if it consumes wild animals such as rodents, birds, and others that contain lungworm larvae and eggs.
  • A cat can become infected with lungworm if it eats snails, slugs, or insects like earthworms, as many of these insects are intermediate hosts for lungworms and carries their eggs and larvae.
  • Lungworm larvae can be found in stagnant water, so if your cat has a habit of drinking water from unsanitary sources, it is likely that it will get lungworms.
  • If your cat consumes food or water contaminated with the feces of a lungworm-infected cat, your cat may become infected because infected cats shed adult lungworms, eggs, and larvae in their stool.

Vertical Transmission

Vertical transmission is a form of indirect transmission that occurs only between a mother and her offspring.

If the mother is positive for the organism, they will pass it on to her offspring during pregnancy, birth, or lactation.

In the case of lungworms, mother cats can pass them on to their kittens through milk.

Direct Transmission (Very Rare)

In cats, direct lungworm transmission is extremely rare.

It is only possible if a healthy cat comes into contact with the respiratory secretions of a lungworm-positive cat that contains parasite eggs, larvae, or the parasite itself, which is highly unlikely (source 1,2,3).

How Common Is Lungworm In Cats?

Lungworms were previously rare in cats, with only a few cases reported; however, this has changed in recent years.

Currently, lungworm infections are very common in cats worldwide and cases of lungworms are common in countries as far as Australia.

According to a new study, approximately 5% of all cats on the globe have lungworms.

Another 2017 statistic shows that lungworms are the second most common parasite detected in cats (10.6%) in Europe.

Lungworms are more common in areas where their intermediate hosts, such as snails, slugs, and earthworms, are plentiful, which is mostly in tropical and humid regions.

Lungworms are common in Europe, particularly in Italy, Spain, France, Germany, and the United Kingdom.

Although the prevalence of lungworm in cats is low in North America, cases have been reported in states such as Florida and California (source 1,2).

How Long Can A Cat Live With Lungworm?

Lungworms can infect cats for up to 9 months, and many cat owners wonder is lungworm in cats is curable and if their infected cats can live a normal life.

Fortunately, lungworm is curable in cats, but the extent of damage done by the parasite to your cat’s lungs and the respiratory tract will determine the cat’s lifespan after infection.

In some cases, lungworm infection in cats is asymptomatic, and no symptoms may appear throughout the cat’s life.

Cats in which the infection is diagnosed early on and appropriate treatment is given, and no major damage to the lungs has occurred have a good prognosis, and will usually live their maximum lifespan.

Senior cats, young kittens, cats with compromised immunity, and cats suffering from other chronic diseases are usually the ones most affected by lungworm infections.

Their lifespan may be reduced depending on their condition and the treatments provided.

Cats that suffered from a combination of lungworm infection along with bacterial respiratory infections are also at higher risk (source 1).

Over-The-Counter Lungworm Treatment For Cats

Since lungworm infection is a parasitic infection, the majority of over-the-counter treatments available to cure it are antiparasitic drugs.

Anti-parasitic drugs are typically extremely dangerous, and veterinarians must exercise extreme caution to avoid overdosing or underdosing the patient.

Vets strongly advise against using over-the-counter drugs to treat lungworm in cats because most cat owners do not know how to calculate the right dose for their cat, and overdosage can result in severe drug reactions that can lead to your cat’s death.

Your cat may not die from the disease, but it will surely die as a result of an overdose or drug reaction.

Natural Treatment For Lungworm In Cats

Natural treatments are usually only effective against worms and parasites found in your cat’s intestines and digestive tract.

However, they are ineffective against lungworms because the larvae of lungworms typically migrate from the intestine to your cat’s lungs, where no natural treatment can reach them.

Only if you can provide natural treatment when the lungworm larvae or adults are in your cat’s intestine will it be beneficial, but there is no way to know when the parasite is in the intestines.

However, there is one thing you can do – regularly feeding your cat pumpkin seeds will help flush out any parasites present in its intestines as they act as natural dewormers (source 1).

Is Lungworm In Cats Contagious To Humans?

Lungworms, in general, are host specific and only affect cats.

Aelurostrongylus abstrusus, the most common lungworm, only infects cats, and no human cases have been reported.

However, one lungworm species, Capillaria aerophila, has zoonotic potential and only a few cases of human capillaries have been reported worldwide.

This parasite typically causes bronchitis with a productive cough in humans.

It is advised that humans practice good hygiene around pets in order to protect themselves and their pets from infections and diseases (source 1).


Lungworm in cats is a common parasitic respiratory infection that affects cats all over the world.

Lungworms are roundworms (nematodes) that infect the lungs of cats.

There are numerous lungworm species that can infect cats, but the most common is Aelurostrongylus abstrusus.

Weight loss, coughing, respiratory sounds, nasal discharge, open-mouth breathing, abdominal breathing, and a few other symptoms are common in cats with lungworm.

Cats that prey on wild rodents and birds and consume insects such as snails, slugs, and earthworms are highly susceptible to lungworms.

Lungworm in cats can be difficult to diagnose because its signs and symptoms overlap with those of several other respiratory diseases and infections in cats.

Fortunately, lungworm in cats is curable, and the majority of cats recover completely after treatment.

Over-the-counter medications are strongly discouraged for treating lungworm in cats, and natural treatments are also less effective in this specific parasitic infection.

Maine Coon Central

Hello! My name is Katrina Stewardson, and I’m a CRAZY CAT LADY! I've been in love with the Maine Coon cat breed ever since we welcomed an adorable male Maine Coon kitten into our home 10 years ago. We called him 'Pippin', but he also goes by the name ‘Pipsteroo’! Our enormous, kind-hearted cat genuinely thinks he's a dog and has convinced me that cats are Man's True Best Friend! UPDATE: We recently adopted two 4-year-old male Maine Coon cats. They are named Mika and Bali.

Recent Posts