Lungworm in Dogs Causes Symptoms Treatments

Lungworm in Dogs: Causes, Symptoms & Treatment

Lungworm in dogs is a parasitic infection caused by various species of worms that primarily reside in the respiratory system, particularly the lungs and airways. One of the most common types of lungworm affecting dogs is Angiostrongylus vasorum, though there are other species such as Crenosoma vulpis and Oslerus osleri that can also cause lungworm infections.

These worms typically have complex life cycles involving intermediate hosts such as snails, slugs, or frogs. Dogs usually become infected by ingesting these intermediate hosts, either through direct ingestion or indirectly by eating contaminated grass, soil, or water. Once inside the dog's body, the larvae migrate through the bloodstream to the lungs, where they mature into adults and lay eggs. These eggs are then coughed up by the dog and either swallowed or passed in faeces, continuing the cycle.

Lungworm infection can lead to various symptoms in dogs, including coughing (which can sometimes be chronic and severe), difficulty breathing, lethargy, weight loss, decreased appetite, and in severe cases, it can lead to respiratory distress and even death if left untreated.

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What is a Lungworm?

Lungworms are a type of parasitic worm that primarily inhabit the respiratory system of their host animals. They belong to various species within the families Metastrongyloidea and Strongylida. These worms are specifically adapted to live within the lungs, bronchi, and trachea of mammals, including dogs, foxes, and other carnivores.

Are there different types of Lungworm in dogs?

Yes, there are different types of lungworm that can affect dogs. The three most common types of lungworms that infect dogs are:

  1. Angiostrongylus vasorum (French Heartworm): Angiostrongylus vasorum is one of the most prevalent lungworm species affecting dogs, particularly in certain regions of the world such as Europe and North America. This lungworm primarily affects the pulmonary arteries and right side of the heart. It has a complex life cycle involving snails and slugs as intermediate hosts. Dogs become infected by ingesting infected intermediate hosts or contaminated material containing infectious larvae.
  2. Crenosoma vulpis (Fox Lungworm): Crenosoma vulpis is another species of lungworm that commonly infects dogs, especially in regions where fox populations are abundant. Unlike Angiostrongylus vasorum, Crenosoma vulpis primarily resides in the bronchi and bronchioles of the lungs. Dogs typically become infected by ingesting infectious larvae found in the environment, such as on grass or in water sources contaminated with infected fox faeces.
  3. Eucoleus aerophilus (Hedgehog Lungworm): Eucoleus aerophilus, formerly known as Capillaria aerophila, is a parasitic worm belonging to the family Capillariidae. Commonly referred to as the "hedgehog lungworm," it primarily infects the respiratory tract of various animals, including dogs, as well as other wild and domestic carnivores. Infection in dogs occurs when they ingest infectious eggs, leading to larval migration to the nasal passages and sinuses, where they develop into adult worms.

While Angiostrongylus vasorum and Crenosoma vulpis are the most well-known species of lungworms affecting dogs, there are other less common species that may also cause lungworm infections in dogs. These include Oslerus osleri (also known as Filaroides osleri or Canine Lungworm), which infects the trachea and bronchi, and Aelurostrongylus abstrusus, which primarily infects cats but can occasionally affect dogs as well.

How do dogs get Lungworm?

Dogs can get lungworm through various routes of exposure to infectious stages of the parasite, depending on the specific species of lungworm involved.

  • Eating snails & slugs: Some lungworms live on intermediate hosts such as snails and slugs. Dogs become infected by eating these creatures, either intentionally or accidentally. This can occur when dogs explore outdoor environments and eat contaminated vegetation, water sources, or other objects such as toys that have been left in the garden.
  • Ingestion of infectious Larvae: Dogs can also get lungworm by eating infectious larvae directly from the environment. Larvae may be present in contaminated soil, water, or on surfaces where infected creatures and animals have left faeces.

  • Inhalation of larvae: In addition to ingestion, dogs may pick up lungworm by inhaling infectious larvae, particularly when sniffing or exploring areas where infected wildlife, such as foxes, have deposited faeces containing larvae.

Once the infectious larvae are eaten or inhaled, they trevel through the dog's body to the respiratory system, where they mature into adult worms and establish themselves in the lungs, bronchi, or bronchioles. From there, they reproduce and release eggs, which are pooped out by the dog and can contaminate the environment, continuing the lifecycle of the parasite.

What are the symptoms of Lungworm in dogs?

Lungworm infection in dogs can cause a range of symptoms, which can vary in severity depending on factors such as the species of lungworm involved, the extent of the infection, and the dog's overall health status.

  1. Coughing: Persistent coughing is one of the most common signs of lungworm infection in dogs. The cough may be dry or productive (producing mucus or blood) and may worsen with exertion or excitement.
  2. Difficulty Breathing: Lungworms can cause inflammation and damage to the respiratory tissues, leading to difficulty breathing or shortness of breath. Dogs may exhibit rapid or laboured breathing, wheezing, or respiratory distress.
  3. Lethargy: Infected dogs may appear tired, lethargic, or weak. They may have reduced energy levels and reluctance to engage in normal activities such as playing or exercising.
  4. Decreased Appetite: Lungworm infection can lead to a loss of appetite or decreased interest in food. Dogs may eat less than usual or show disinterest in their meals.
  5. Weight Loss: Chronic lungworm infection can result in weight loss despite a decrease in appetite. This is often due to the metabolic demands associated with fighting off the infection and the energy expended in breathing.
  6. Nasal Discharge: Some dogs with lungworm infection may develop nasal discharge, which can be clear, mucus like, or tinged with blood. The discharge may be accompanied by sneezing or nasal congestion.
  7. Exercise Intolerance: Dogs with lungworm infection may exhibit exercise intolerance or reluctance to engage in physical activity due to respiratory distress or discomfort.
  8. Gagging or Vomiting: In severe cases, dogs may experience gagging or vomiting, particularly if they cough up mucus or blood associated with the infection.
  9. Fever: Lungworm infection can sometimes cause fever, although this symptom may not always be present or readily apparent.
  10. Pale Gums: In advanced or severe cases, dogs may develop pale gums (due to anaemia) or cyanosis (bluish discoloration of the mucous membranes) as a result of impaired oxygenation.

It's important to note that the severity and combination of symptoms can vary widely among individual dogs, and some infected dogs may show only mild or intermittent signs of illness.

How do you know if your dog has Lungworm?

The most common method for diagnosing lungworm infection in dogs involves analysing faecal samples (and the use of a lungworm test kit) for the presence of lungworm eggs or larvae. This is usually done through faecal flotation or faecal sedimentation techniques, which allow for the concentration and identification of parasitic eggs or larvae present in the faeces.

How do you treat Lungworm?

The treatment of lungworm infection in dogs typically involves a combination of anthelmintic medications to eliminate the adult worms and supportive care to manage clinical signs and complications associated with the infection.

Anthelmintics are medications specifically designed to kill parasitic worms. The choice of anthelmintic and treatment protocol may vary depending on factors such as the species of lungworm involved, the severity of the infection, and the dog's overall health status. Commonly used anthelmintics for treating lungworm in dogs include:

  • Fenbendazole (brand names Panacur®, Safe-Guard®): Fenbendazole is a broad-spectrum anthelmintic that is often effective against lungworms. It works by disrupting the parasites' ability to absorb nutrients, leading to their death. Fenbendazole is typically administered orally once daily for a specified duration, as prescribed by a veterinarian.
  • Moxidectin (brand names: Advantage Multi®, Advocate®, ProHeart®): Moxidectin is another anthelmintic that is effective against lungworms. It belongs to the macrocyclic lactone class of drugs and works by paralysing and killing the parasites. Moxidectin is available in various formulations, including oral tablets or spot-on treatments, and the treatment protocol may vary depending on the product used and the manufacturer's recommendations.
  • Natural Remedies: At present there are no effective natural remedies that can treat a confirmed lungworm infection.

What happens if you don't treat Lungworm in dogs?

If left untreated, lungworm infection in dogs can lead to various complications and potentially life-threatening consequences. Here are some potential risks and consequences of untreated lungworm infection in dogs:

  1. Progression of Respiratory Symptoms: Lungworms can cause inflammation and damage to the respiratory tissues, leading to progressive respiratory symptoms such as coughing, difficulty breathing, wheezing, and respiratory distress. Without treatment, these symptoms may worsen over time, impairing the dog's ability to breathe and leading to significant discomfort and distress.
  2. Secondary Infections: Lungworm infection can weaken the dog's immune system and predispose them to secondary bacterial or fungal infections in the respiratory tract. These secondary infections can exacerbate respiratory symptoms, lead to complications such as pneumonia, and further compromise the dog's respiratory function.
  3. Chronic Illness: In some cases, lungworm infection can become chronic if left untreated, leading to persistent respiratory symptoms, recurrent infections, and long-term damage to the respiratory tissues. Chronic lungworm infection can significantly impact the dog's quality of life and may require prolonged treatment to manage clinical signs and complications.
  4. Respiratory Failure: In severe cases of untreated lungworm infection, respiratory failure can occur due to severe inflammation, damage to the lungs, or obstruction of the airways by worms or inflammatory debris. Respiratory failure is a life-threatening condition that requires immediate veterinary intervention, including supportive care such as oxygen therapy and emergency treatment to restore respiratory function.
  5. Systemic Complications: Lungworm infection can have systemic effects on the dog's body beyond the respiratory system. Chronic inflammation and immune dysregulation associated with lungworm infection can lead to systemic illness, including weight loss, lethargy, anaemia, and organ dysfunction.
  6. Decreased Quality of Life: Untreated lungworm infection can significantly impact the dog's overall health and well-being, leading to reduced quality of life, impaired mobility, and chronic discomfort. Dogs may experience fatigue, exercise intolerance, and a decreased appetite, further contributing to their diminished quality of life.

In summary, untreated lungworm infection in dogs can have serious consequences, including progressive respiratory symptoms, secondary infections, chronic illness, respiratory failure, systemic complications, and decreased quality of life. Prompt diagnosis and appropriate treatment are essential for effectively managing lungworm infection and minimising the risk of complications and long-term health consequences for affected dogs.

How common is Lungworm in dogs?

The prevalence of lungworm infection in dogs can vary depending on factors such as geographical location, environmental conditions, dog population density, and the presence of intermediate hosts. While specific statistical data on the global prevalence of lungworm in dogs may be limited, several studies and surveys have provided insights into its occurrence in various regions:

In Europe, lungworm infection, particularly caused by Angiostrongylus vasorum, is considered relatively common in parts of Europe, including the United Kingdom, Ireland, France, Germany, and Scandinavia. Studies have reported prevalence rates ranging from 2% to 50% in different regions and populations of dogs.

Can you prevent Lungworm in dogs?

Whilst it is impossible to completely prevent the chances of your dog catching lungworm, there are precautions you can take to minimise the risks.

Don’t leave toys in the garden: unattended toys and balls in the garden can hide slugs and snails that your dog may accidentally eat whilst playing. Once playtime is over, take toys inside.

Practising good hygiene: Promptly remove and disposing of faeces in the garden from foxes and hedgehogs which may harbour larvae. If your dog likes to roll in fox poo ensure you bath your dog as soon as you get home to prevent your dog licking the area. Regularly cleaning and disinfecting food and water bowls that are left outside is also imperative.

What do Lungworm look like?

While lungworms vary in appearance depending on the specific species and stage of development, they generally share some common characteristics:

  1. Slender and Elongated Body: Adult lungworms typically have a slender and elongated body, which allows them to navigate and inhabit the respiratory tract of their host. The body may appear cylindrical or slightly flattened, depending on the species.
  2. Tapered Ends: Lungworms often have tapered ends, with the anterior (front) end being more pointed and the posterior (rear) end tapering to a rounded or pointed tip. This morphology allows them to move through the respiratory tissues and navigate within the host's airways.
  3. Translucent or White Colour: Adult lungworms may appear translucent or white in colour, especially when freshly dissected or observed under a microscope. Their coloration may vary depending on factors such as the presence of internal organs or the degree of fixation and preservation.
  4. Internal Structures: Lungworms have internal structures and organs necessary for their survival and reproduction, including a digestive system, reproductive organs, and muscles for movement. These structures may not be readily visible without magnification or specialised techniques such as dissection.
  5. Size: The size of lungworms can vary depending on the species, stage of development, and sex. Adult lungworms may range from a few millimetres to several centimetres in length, with females often being larger than males.

It's important to note that while lungworms may be visible to the naked eye under certain circumstances, such as during post-mortem examinations or in heavily infected individuals, they are often microscopic and may require specialised techniques, such as faecal flotation or histological examination, for detection and identification.

Can Lungworm be passed to humans?

While the risk of transmission of lungworms from dogs to humans is generally low, certain precautions can help reduce the risk of infection:

  • Practising good hygiene, such as washing hands thoroughly after handling dogs, cleaning litter boxes, or working in the garden, can help minimise the risk of exposure to potentially contaminated faeces or environments.
  • Avoiding contact with wildlife or environments where infected intermediate hosts (such as snails, slugs, or crustaceans) are prevalent can reduce the risk of accidental ingestion of infective larvae.
  • Seeking prompt medical attention if symptoms suggestive of lungworm infection develop after potential exposure to infected animals

What does a Lungworm cough sound like?

The cough associated with lungworm infection in dogs can vary in sound and severity depending on factors such as the species of lungworm involved, the extent of the infection, and the individual dog's respiratory health. However, there are some common characteristics that may help distinguish a lungworm cough from other types of coughing in dogs:

  1. Dry and Hacking: A lungworm cough may be dry and hacking in nature, resembling a repetitive, non-productive cough. The cough may sound harsh or raspy and may be more pronounced during certain activities, such as exercise or excitement.
  2. Persistent: Lungworm coughing in dogs may be persistent, meaning it occurs frequently or repeatedly throughout the day, even when the dog is at rest. The cough may occur in bouts or episodes, with multiple coughs occurring in quick succession.
  3. Wheezing or Gagging: In some cases, dogs with lungworm infection may exhibit additional respiratory signs such as wheezing, gagging, or retching, particularly if the infection has progressed or if there are complications such as inflammation or obstruction of the airways.
  4. Exercise-Induced: Lungworm coughing may be exacerbated by physical activity or exercise, as increased respiratory effort and airway irritation can trigger coughing episodes. Dogs with lungworm infection may cough more frequently or intensively during walks, playtime, or other activities that require exertion.
  5. Changes in Breathing Pattern: Dogs with lungworm infection may exhibit changes in their breathing pattern, such as rapid or laboured breathing, shallow breaths, or increased effort to inhale or exhale. These changes may accompany coughing episodes and can indicate respiratory distress.

It's important to note that while a dry, hacking cough is often associated with lungworm infection in dogs, other respiratory conditions or diseases can cause similar coughing symptoms.

Can you treat Lungworm naturally?

No. Many natural worming remedies such as Grapefruit Seed Extract or Pumpkin Seeds effectively target parasites in the digestive tract. As lungworms reside in the lungs rather than in the digestive system, once an infection has taken hold, we recommend treating with medication to ensure the lungworm infection is dealt with swiftly. Untreated lungworm infections can have serious consequences for dogs.

Can you see Lungworm in dog's poo?

No. In most cases, lungworms are not visible in dog faeces with the naked eye. This is because lungworms typically inhabit the respiratory tract of their host animals, including dogs, and their eggs or larvae are expelled from the body through coughing or swallowing rather than passing directly through the digestive tract.

Can puppies get Lungworm from their mothers?

Yes, puppies can potentially acquire lungworm infections from their mothers, although it's less common compared to other modes of transmission such as ingestion of infective larvae from the environment. The transmission of lungworms from mother to puppy can occur through several routes:

  1. Transplacental Transmission: In some cases, larvae of certain species of lungworms may be able to cross the placental barrier and infect developing foetuses in the uterus. This is known as transplacental transmission and can occur if the mother is infected with lungworms during pregnancy. However, transplacental transmission of lungworms appears to be relatively rare compared to other routes of transmission.
  2. Transmission through Milk: Another potential route of transmission is through the ingestion of infective larvae present in the mother's milk. If the mother is infected with lungworms, larvae may be shed in her milk and ingested by nursing puppies during suckling. This can lead to infection in the puppies' gastrointestinal tract, from which larvae may migrate to the respiratory system and develop into adult worms.

While transmission of lungworms from mother to puppies is possible, the frequency and significance of this mode of transmission may vary depending on factors such as the species of lungworm involved, the mother's health status and level of infection, and environmental factors. Additionally, the presence of other sources of infection in the environment, such as contaminated soil or intermediate hosts, may contribute more significantly to the overall risk of lungworm infection in puppies.

The use of a Lungworm Test Kit is the best way to prevent your dog from being overwhelmed with a lungworm infection. A Lungworm Test Kit or a Combo Worm & Lungworm Test Kit should be undertaken every 3 months if regular chemical wormers are not being used.

With wags and woofs,
Laura, Dolly & Reggie

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