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Does Your Garden Have Critters Carrying Lungworm?

Snails, Slugs, And Frogs..Watch Out For These Critters In Your Garden! Mollusks and frogs are often found in gardens and landscapes, gliding and hopping across plants and leaves as they look for vegetable matter, decomposing plants, and dead animals to eat.  These seemingly harmless critters are actually very dangerous to your dog!

Snails, slugs, and frogs are called intermediate hosts, as they are needed for the worms to grow and mature before they can infect other hosts and complete their life cycle.  Adult lungworms are long and thin parasitic worms that range from 1.5-4cm long.

A dog can contract a lungworm if he or she eats larvae in a slime trail or by eating a snail, a slug, or a frog whole.  Dogs can also accidentally eat infected slugs if the mollusks are stuck on a toy or their fur.


The Lifecycle of Lungworms

There is a potential increased risk of infection in late summer when the intermediate hosts such as snails, slugs, and frogs are more prevalent.  Below are the steps of the life cycle of the lungworm in dogs after ingesting an intermediate host.

  1. Feces with first stage larvae are eaten by snails, frogs, or slugs.  They are considered intermediate hosts at this point.
  2. The larvae mature into the third stage in a snail, frog, or slug.
  3. Next, a dog eats the infected snail, frog, or slug.
  4. The larvae penetrate the dog’s intestines and enter the bloodstream.
  5. The larvae move to the central nervous system to mature to the sub-adult stage.
  6. Sub-adults then move back into the bloodstream and mature in the right ventricle of the heart and in the pulmonary artery.
  7. There, females lay eggs which hatch into larvae.  The eggs and larvae travel through the bloodstream and into the lungs, where they are coughed up by the dog.
  8. The larvae are then swallowed by the dog and excreted in their feces.
  9. The life cycle begins again.


Problems Caused By Eating Intermediate Hosts

Snails, Slugs, And Frogs..Watch Out For These Critters In Your Garden! Ingesting lungworm larvae by eating a snail, slug or frog can lead to many physical problems in a dog.  The larvae move through the body and live inside the heart and blood vessels.

This can lead to coughing, lethargy, weight loss, vomiting, and diarrhea.  More severe symptoms can include heart problems, breathing problems, and pneumonia.

Additionally, the worms can lead to hemorrhages in the lungs, intestines, liver, eyes, and spinal cord.  If you believe that your dog has contracted a lungworm, contact your veterinarian immediately!


Prevent Your Dog From Lungworm

Snails, Slugs, And Frogs..Watch Out For These Critters In Your Garden! To prevent your dog from ingesting an intermediate host, try to limit exposure to snails, slugs, and frogs as much as possible.  Feed your dog inside rather than outside, and avoid walking your pup in the early morning, late in the evening, or during or after rainy weather.

Intermediate hosts are more likely to be outside during these times, and avoiding intermediate hosts may help decrease your dog’s risk of infection.

You can take prevention one step further with parasitic worm preventative medications.  Anthelmintics (anti-parasitic drugs) are available over-the-counter or by prescription from your veterinarian.

Treatments of these medications can be administered monthly in order to prevent infections and to destroy larvae that may already be in the tissues of the body.  This treatment can also help prevent the spread of lungworm in the environment, and help minimize the spread of infection.


Does your dog like to pick up mollusks and frogs?  What do you do to keep your dog from eating these critters?  Let us know and help other dog owners protect their pups from lungworm!