Lungworm Infection in Dogs

Your dog has a dry, nagging cough that just won’t clear up. You’ve ruled out the obvious no fever, still eating fine, playing normally between coughing fits. If antibiotics or a wait-and-watch approach haven’t helped, it might be time to consider a less commonly discussed cause: lungworm.

Key Takeaways

• Lungworm infection in dogs is usually caused by a parasite called Oslerus osleri, which lives in nodules inside the trachea.
• India is one of the countries where this infection has been documented, alongside the US, UK, South Africa, and Australia.
• Puppies typically get infected through an infected mother’s saliva or feces, most often while she’s cleaning them.
• Signs range from a mild, occasional dry cough to severe, persistent coughing and real breathing distress some dogs show no signs at all.
• Treatment can be genuinely difficult, and vets often combine long courses of antiparasitic medication with surgical removal of the tracheal nodules.

What Is Lungworm Infection?

Lungworm infection in dogs refers to a group of parasitic worms that settle in the airways, most commonly the tracheal worm Oslerus osleri. These infections have been documented across a wide geographic spread, including the United States, South Africa, New Zealand, India, Great Britain, France, and Australia, since lungworm infections in dogs are usually caused by the tracheal worm Oslerus osleri, which have been found in the United States, South Africa, New Zealand, India, Great Britain, France, and Australia. That means this isn’t a foreign, irrelevant condition for Indian pet parents it’s one that’s been recorded within the country.

The adult worms live inside small nodules that form in the trachea, or windpipe, and the eggs they lay hatch right there, since adult lungworms live in nodules in the trachea of dogs, and larvated eggs laid by adults hatch there. The good news is that this specific infection is genuinely uncommon, since infection is infrequent in dogs but “uncommon” isn’t the same as “impossible,” and it’s worth knowing the signs.

How Do Dogs Get Lungworm?

The transmission route for the most common lungworm is refreshingly simple, if a little uncomfortable to think about: puppies typically become infected through direct contact with an infected adult dog’s feces or saliva most often when an infected mother licks her pups, since pups become infected from the feces or saliva of an infected dog, for example when an infected mother licks her pups.

Other lungworm species that can infect dogs have different life cycles. Eucoleus aerophilus (also called Capillaria aerophila), for instance, spreads when dogs eat food or drink water contaminated with larvated eggs. Once swallowed, the eggs hatch in the intestine and the larvae travel to the lungs through the bloodstream, since dogs become infected by eating food or drinking water that is contaminated with larvated eggs, and after being eaten, the eggs hatch in the intestine and then travel to the lungs through the circulatory system. Other lungworms that can infect dogs include Crenosoma vulpis, Eucoleus aerophilus, and Filaroides hirthi — the last of which lives directly within lung tissue rather than in tracheal nodules, since other lungworms that can infect dogs include Crenosoma vulpis, Eucoleus aerophilus, and Filaroides hirthi, with F hirthi similar to Oslerus osleri except that the worms live within the lung tissue.

Symptoms of Lungworm in Dogs

Lungworm signs cover a wide spectrum, and that range is exactly what makes it tricky to spot early.

• Mild cases: a moderate, dry cough with a slightly increased breathing rate
• Severe cases: persistent, forceful coughing along with genuine respiratory distress, or even respiratory failure
• Silent cases: some infected dogs show no visible signs at all

Signs of lungworm infection range from moderate, dry coughing with slightly increased respiratory rates to severe, persistent coughing and respiratory distress or even failure, though infections with no visible signs can also occur, since signs of lungworm infection range from moderate, dry coughing with slightly increased respiratory rates to severe, persistent coughing and respiratory distress or even failure, and infections with no visible signs can also occur.

The reassuring part: death is relatively uncommon in dogs infected with these particular lungworms, since death is relatively uncommon in dogs infected with these lungworms. That said, a small number of other parasites that live in the heart’s right ventricle such as Angiostrongylus vasorum and the heartworm parasite Dirofilaria immitis can cause lung disease as well, sometimes alongside heart-related signs, in certain regions of the world, since some nematodes that inhabit the right ventricle of the heart, such as Angiostrongylus vasorum and Dirofilaria immitis, both found in dogs in certain areas of the world, may be associated with lung disease, and signs relating to a heart or a lung syndrome, or to a combination of both, may occur. This is one reason a persistent, unexplained cough always deserves a proper vet workup rather than a guess.

How Vets Diagnose Lungworm

Diagnosing lungworm can genuinely challenge even an experienced vet, and understanding why helps explain why testing sometimes takes more than one attempt.

Diagnosis is based on a combination of clinical signs, known transmission patterns, and finding larvae in the feces, since diagnosis of lungworm infection is based on signs, known transmission patterns, and presence of larvae in feces. Vets may also use bronchoscopy examining the airway with an endoscope alongside X-rays as helpful diagnostic tools, since examination of the airways with an endoscope and x-rays can be helpful tools.

Here’s the tricky part: infected dogs don’t always pass larvae in their feces consistently, and when they do, the numbers can be genuinely low, which can lead to false negatives on a single test, since it can be a challenge for the veterinarian to diagnose lungworm because infected animals do not always pass the larvae in their feces, and when they do, they may be few in number. To work around this, vets can perform a bronchoscopy specifically to collect tracheal washings, which are then examined for eggs, larvae, and white blood cells that point to active infection, since bronchoscopy can be used to collect washings from the trachea to examine for eggs, larvae, and white blood cells.

Treatment for Lungworm Infection

Lungworm infection in dogs can be difficult to treat, but the outlook isn’t hopeless. There’s solid evidence that appropriate antiparasitic drugs work, especially when combined with surgical removal of the nodules forming in the trachea, since lungworm infection in dogs can be difficult to treat, but there is evidence that appropriate antiparasitic drugs are effective, particularly when combined with surgical removal of the nodules in the trachea. What surprises many pet parents is how long treatment can run — antiparasitic medication may need to continue for up to two months to fully clear the infection, since it may be necessary to continue antiparasitic treatment for up to 2 months.

For the other lungworm species, such as Eucoleus aerophilus, treatment with the right antiparasitic drug is generally more straightforward and effective, since treatment with appropriate antiparasitic drugs is usually effective for this infection. Veterinary literature on related lung nematodes describes courses of fenbendazole or ivermectin as effective options, underscoring that with the right diagnosis, most lungworm cases do respond to treatment patience with the process matters more than anything else.

Broad-spectrum dewormers such as DRONTAL PLUS TASTY TABLET and MILBEMAX DOG TABLET are commonly used as part of a dog’s regular deworming routine, and your vet may recommend a similar broad-spectrum product or a lungworm-specific antiparasitic regimen — once diagnosis is confirmed. Never start treatment for lungworm without your vet’s guidance, since dosing and duration vary significantly by species and severity.

Caring for a Dog With Lungworm

While your dog is being treated, keep exercise gentle to avoid triggering coughing episodes, and stick closely to the full medication course your vet prescribes, even after the cough seems to have settled — stopping early is one of the most common reasons treatment fails to fully clear the infection. If you have multiple dogs at home, be mindful that close contact, shared bedding, and grooming between dogs can pass the parasite along, so keep an infected dog’s living space cleaned and separated where practical during treatment. A herbal immunity supplement such as IMMUNOL LIQUID can support your dog’s overall recovery alongside the prescribed antiparasitic course, though it’s not a substitute for the treatment itself.

Frequently Asked Questions

Is lungworm the same as heartworm in dogs?
No, though they’re related in an important way. Lungworms like Oslerus osleri live in the trachea or lung tissue itself, while heartworm (Dirofilaria immitis) lives in the heart’s right ventricle. Both can cause respiratory symptoms, and in certain regions, heart-dwelling parasites are specifically linked to lung disease too, which is why vets consider both when investigating a persistent cough.

Can I catch lungworm from my dog?
 No, the lungworm species that infect dogs are not known to spread to humans. The transmission routes feces, saliva, or contaminated food and water between animals are specific to dogs and other animals, not people.

How long does lungworm treatment take?
It varies by species and severity. For the tracheal worm Oslerus osleri, antiparasitic treatment may need to continue for up to two months, sometimes alongside surgical removal of tracheal nodules. Other lungworm species generally respond more quickly to appropriate medication.

Can puppies get lungworm from their mother even if she shows no symptoms?
Yes. Since transmission most commonly happens through an infected mother’s saliva or feces while she cleans her pups, an adult dog carrying the parasite with no visible signs can still pass it on to her litter.

Is a persistent dog cough always a sign of lungworm?
Not necessarily a chronic cough has many possible causes, including kennel cough, laryngitis, and lung flukes, among others. Lungworm is one specific possibility your vet will consider, particularly if more common causes have been ruled out or don’t respond to standard treatment.

References

1. Merck Veterinary Manual — Lungworm Infection in Dogs
2. Merck Veterinary Manual — Lungworm Infection in Animals (Professional Content)
3. Merck Veterinary Manual — Lung Nematodes in Small Animals (Professional Content)