Lung Worm In Dogs

Here at Saint Leonard Veterinary Centre we pride ourselves on giving you, our clients, and your fur babies, the very best treatment and advice we can. To enable us to do this we do a variety of things; we keep educating ourselves with continuous professional development, we talk to our colleagues at other veterinary practices, and we keep an ear to the ground about diseases in or around our area.

This particular blog, though short and sweet, concerns a parasite that affects dogs, Angiostrongylus vasorum, or Lungworm to give it its simple name; and this parasite may be short (1.5-2cm in length) but it is far from sweet in nature. There is another type of lungworm that affects cats too, but we won’t be addressing that today.


Lungworm is what we call an”emerging” disease because it is getting increasingly common. Until recent times it had been largely confined to a small number of “hot spots” in the U.K’s southern region; however over the last few years it has been clinically confirmed in various parts of the country.

Derbyshire has seen four cases identified in various parts of the county; two within Derby City centre itself. At the moment the precise cause of this spread isn’t clear, although we do have several theories including wildlife becoming more frequent visitors to the urban environment and the increased travel habits of pets both abroad and within the U.K. These factors mean that other parasites and ticks are also being spread far and wide, unfortunately.

Lungworms are parasitic meaning they need a host to complete their life cycle. Slugs and snails carry the lungworm larvae and infect dogs when ingested by them. Annoyingly, it is possible that just swallowing an infected slugs’ slime could infect your beloved pooch. Although slugs and snails secrete substances with a noxious taste, there are some persistent hounds that ignore Mother Natures’ warning and still lick or eat things they shouldn’t. Any age or breed of dog can become infected with lungworm but younger ones are more susceptible, and they’re probably the ones that are more curious about slugs and snails; grubbing about in dirt, under-growth and puddles is great fun to them!


After eating the growing, developing larvae from a slug or snail, the dog passes them out in its faeces (poop) and the waiting larvae are then picked up by whatever ingests this infected waste. Spring and autumn are peak times for slug and snail activity and this tends to be when infected ones are ingested, spreading the parasite rapidly within the Canine community. Once dogs are infected, adult lungworms live in their heart and the major blood vessels supplying the lungs, where they cause a raft of potentially serious problems.

An absolute diagnosis of lungworm is difficult and involves a variety of diagnostic methods such as blood samples for DNA, analysis of stool samples for the presence of eggs and larvae, chest X-rays, and even Bronchoscopy (looking inside the lungs themselves with a tiny camera). Interestingly, even if we don’t find worms it doesn’t mean your dog isn’t infected; sometimes we can base a diagnosis on your pets’ history, compatible clinical signs, and their response to the lungworm treatment.

Infection by lungworm can be fatal if left untreated, but killing this parasite is relatively simple; and when the disease is detected early on it isn’t particularly expensive or invasive to treat, good news for you and your dog. As with most diseases, the more advanced the condition is, the more permanent any damage/effects is likely to be, and therefore the more complex (and costly) veterinary intervention would need to be.

At Saint Leonard Veterinary Centre our philosophy has always been “prevention is better than cure” and happily there are preventative measures available for lungworm infection. If you suspect your dog has eaten a slug or snail but isn’t symptomatic (showing signs of infection), just get in contact and we’ll happily give them a precautionary check over.

Only worming products supplied through Veterinarians (i.e. yours truly) can prevent lungworm; products from supermarkets and chemists are just simply not effective.

With lungworm it is absolutely VITAL that the preventative products are administered monthly, especially in areas known to have regular cases of lungworm or for dogs that frequently eat slugs and snails. Infrequent (or an absence of) treatment risks disease and possibly death in your much-loved dog, something we all want to avoid. Don’t worry though, the team here at Saint Leonard Veterinary Centre are in your corner and will remind you of your pets’ treatment schedule.

Until next time; stay safe, stay well, and be happy 🙂