Labrador Retriever puppy exploring grass outdoors, where roundworm and other parasites are commonly picked up
on September 18, 2026

Worms in Dogs: Types, Symptoms & Treatment (UK Guide)

Most dogs will pick up worms at some point - roundworm, tapeworm and, increasingly in the UK, lungworm - usually with few or no obvious symptoms, which is exactly why regular worming matters more than watching for signs. UK survey data shows 97% of dogs fall into the highest-risk category for worm exposure, yet most owners worm their dogs far less often than vets recommend, leaving a real gap between perceived and actual risk.

Written by Jamie Sinclair, who writes about canine health, nutrition, and everyday care for Doggy Dailies - focused on translating veterinary research and real ingredient science into practical, honest guidance UK dog owners can use. Health-claim sections reviewed against formulation guidance from Lourdes María Arnedo Amat.

Last updated: 18 September 2026

Table of Contents

The real worming risk gap in the UK

A 2020 survey of 500 UK dog owners, published in Parasites & Vectors, found that under the European Scientific Counsel Companion Animal Parasites (ESCCAP UK & Ireland) risk-based worming guidelines, 97% of dogs fell into the highest-risk category (Group D) - meaning they hunt, scavenge, eat raw food, live with young children, or have another factor that raises zoonotic risk. Despite this, owners in the survey wormed their dogs an average of just 3.1 times a year, and only 8.6% of Group D dogs were wormed as often as ESCCAP's monthly recommendation for that risk category.

In plain terms: almost every dog in the UK is in the group that needs the most frequent worming, but the vast majority of owners are worming considerably less often than that. This isn't a criticism of individual owners - most simply aren't told which risk group their dog falls into - but it's the single biggest reason worms remain so common despite widely available treatment.

The main types of worms affecting UK dogs

Four worm types account for almost all cases seen by UK vets:

  • Roundworm (Toxocara canis) - the most common, especially in puppies. Adult roundworms can reach up to 15cm long and live in the intestine, and puppies can be born already infected via the placenta.
  • Tapeworm (Dipylidium caninum and others) - segmented worms, often first noticed as small, rice-grain-like segments around the tail or in bedding. Usually picked up from swallowing an infected flea.
  • Lungworm (Angiostrongylus vasorum) - potentially fatal, picked up from eating slugs or snails (or licking surfaces they've crossed). Covered in detail below, since it's the fastest-changing risk of the four.
  • Whipworm and threadworm - less common in the UK than the three above, but can cause chronic diarrhoea and weight loss where present.

Symptoms of worms in dogs

The uncomfortable truth is that many worm infections cause no visible symptoms at all, especially early on - which is exactly why relying on symptoms rather than a regular worming schedule leaves gaps. When symptoms do appear, they can include:

  • A dull, dry or "pot-bellied" appearance, especially in puppies
  • Visible worms or segments in faeces or around the tail (rice-grain-like for tapeworm, spaghetti-like for roundworm)
  • Diarrhoea, sometimes with mucus or blood — if this becomes a recurring pattern rather than a one-off, our guide to colitis in dogs covers the other common causes of colon inflammation, and our guide to giardia covers another common intestinal parasite with very similar symptoms
  • Vomiting, occasionally with visible worms present
  • Weight loss or a dull coat despite normal appetite
  • Excessive scooting or licking around the anus
  • Lethargy, coughing, or breathing difficulty (specific to lungworm - see below)

Why lungworm is a growing UK concern

Beagle sniffing a green garden lawn, the kind of damp grass where slugs and snails carrying lungworm larvae are found

Lungworm deserves its own section because, unlike the other worms here, it's genuinely spreading rather than staying static. Foxes act as a wildlife reservoir for the parasite, and UK surveillance data shows infection rates in fox populations rose from 7.3% in 2005 to 18.3% in 2014 - roughly a two-and-a-half-fold increase in under a decade. The disease has also spread geographically: originally concentrated in hotspots around Cornwall and South Wales, it's now confirmed across the South East, the Midlands, the North of England, Scotland (including Glasgow) and Northern Ireland.

Dogs pick up lungworm larvae by eating infected slugs or snails - directly, or accidentally while eating grass, drinking from puddles, or playing with toys left outside. Symptoms can be vague at first (coughing, tiring more easily on walks) but the disease can progress to serious breathing difficulty and abnormal bleeding or bruising, and can be fatal if untreated. Because slug and snail activity increases with mild, damp weather, milder UK winters are likely part of why the parasite's range keeps expanding.

How dogs actually pick up worms

  • Roundworm: from the mother before or after birth, from contaminated soil or grass where infected animals have defecated, or from eating an infected rodent
  • Tapeworm: almost always from swallowing an infected flea while grooming - which is why flea control and worming go hand in hand
  • Lungworm: from eating slugs, snails, or slime trails on grass, toys, or water bowls left outdoors
  • Whipworm: from contaminated soil, particularly in areas where many dogs are walked

Treating worms in dogs

Effective worming treatments are available as tablets, spot-on treatments, or granules, and different products cover different worm types - a general roundworm-and-tapeworm wormer won't necessarily cover lungworm, so it's worth checking with your vet that your chosen product covers the risks relevant to your dog. Prescription and vet-recommended wormers are generally more reliable than supermarket or pet-shop own-brand products, since coverage and effectiveness vary considerably between products.

Puppies need a more frequent worming schedule than adults, starting from around two weeks old and continuing every 2-3 weeks until 12 weeks, then monthly until six months, reflecting how quickly they can pick up and pass on infections at that age.

A realistic worming schedule

Given that ESCCAP's own survey data found 97% of UK dogs sit in the highest-risk group, most owners should treat "worm regularly" as meaning considerably more often than the 3.1 times a year the average owner currently manages:

  • Ask your vet which risk group your dog falls into. Dogs that scavenge, hunt, eat raw food, live with young children, or have regular contact with slugs/snails or livestock areas fall into the higher-risk groups that need treatment as often as monthly.
  • Don't rely on visible symptoms. As covered above, many infections show no obvious signs, particularly in early or light infections.
  • Treat fleas and worms together. Since tapeworm is transmitted by fleas, a flea infestation without matching worm treatment is a near-guaranteed route to tapeworm.
  • Consider lungworm coverage specifically if you live in or have travelled to any of the areas above, or your dog regularly explores damp grass, puddles, or garden areas where slugs and snails are active.
  • Pick up faeces promptly on walks and in the garden, since this breaks the environmental transmission cycle for roundworm and whipworm.

Can worms in dogs affect people?

Yes - this is one of the genuine zoonotic risks behind ESCCAP's risk-group system. Toxocara canis (roundworm) eggs shed in dog faeces can survive in soil for extended periods and, in rare cases, cause toxocariasis in people, particularly children, if ingested from contaminated soil or unwashed hands. This is part of why regular worming and prompt faeces pick-up matter beyond just the dog's own health, especially in households with young children.

When to see a vet

Contact your vet promptly if your dog shows:

  • Visible worms or segments alongside weight loss or a swollen abdomen
  • Persistent vomiting or diarrhoea, especially with visible worms present
  • A new cough, unusual tiredness on walks, or laboured breathing (potential lungworm signs - treat as urgent)
  • Unexplained bruising or bleeding (also a lungworm warning sign)
  • Any symptoms in a puppy, which can deteriorate faster than in adult dogs

Frequently asked questions

How often should I worm my dog?

ESCCAP UK & Ireland recommends worming as often as monthly for dogs in the highest-risk category, which UK survey data suggests covers around 97% of dogs. Ask your vet which risk group your dog falls into and follow their specific recommendation rather than a generic annual or twice-yearly schedule.

Can I see worms if my dog has them?

Sometimes, but not reliably. Tapeworm segments look like small grains of rice around the tail or in bedding, and roundworms can appear spaghetti-like in vomit or faeces. Many infections, especially light or early ones, show no visible worms at all.

Is lungworm really becoming more common in the UK?

Yes. UK fox surveillance data shows infection rates rising from 7.3% in 2005 to 18.3% in 2014, and the parasite's geographic range has expanded from original hotspots in Cornwall and South Wales to most of the UK, including Scotland and Northern Ireland.

Do indoor dogs need worming too?

Yes. Fleas (which transmit tapeworm) can be brought indoors on clothing or other pets, and most dogs still go outside for walks and toileting, giving ample opportunity to pick up roundworm or lungworm even without regular outdoor access.

Can worms in my dog make me or my children ill?

It's rare, but roundworm eggs shed in dog faeces can, in some cases, cause illness in people (toxocariasis), particularly children, if soil contaminated with eggs is ingested. Regular worming and promptly picking up faeces reduce this risk considerably.

Does one wormer treat every type of worm?

Not always. Many common wormers cover roundworm and tapeworm but not lungworm, which needs a specific product. Ask your vet to confirm your chosen treatment covers all the worm types relevant to your dog's risk factors and location.

Sources

  • Wright, I. et al. "Survey of UK pet owners quantifying internal parasite infection risk and deworming recommendation implications." Parasites & Vectors (2020). link.springer.com
  • Vet Times. "Angiostrongylus vasorum: where is it, and what are the risks?" vettimes.com
  • ESCCAP UK & Ireland. esccapuk.org.uk
  • PDSA. "Worms in dogs." pdsa.org.uk

This article is for general information and doesn't replace advice from your vet, who can recommend the right worming product and frequency for your individual dog. If you suspect lungworm specifically - coughing, tiredness, unusual bruising - contact your vet promptly.