How Lungworm Is Diagnosed

It starts with the story

Diagnosis usually begins with your animal’s history: a cough that won’t clear, exposure to slugs, snails or contaminated grazing, hunting behaviour, or — in horses — sharing pasture with donkeys. These clues point the vet toward lungworm even before testing.

Common tests

Baermann faecal test

The classic test for lungworm. A fresh faecal sample is processed so that any live larvae migrate out and collect where they can be examined under a microscope. Because shedding can be intermittent, vets often test samples collected over three consecutive days to improve accuracy.

Routine faecal examination

Standard worm-egg counts may pick up some species, but several lungworms shed larvae rather than eggs and can be missed on an ordinary float — which is why the Baermann method is preferred.

Blood and antigen tests

For the dog lungworm Angiostrongylus vasorum, specific blood antigen tests are available and are often quicker and more reliable than finding larvae in faeces.

Imaging and airway sampling

Chest X-rays or ultrasound can show characteristic lung changes. In some cases a vet will use a bronchoscope to look inside the airways or collect a sample of airway fluid for analysis.

What to bring to your appointment

• A note of when the cough started and what makes it worse.
• Whether your animal hunts, scavenges or has access to slugs and snails.
• For livestock, grazing history and whether other animals are affected.
• Fresh faecal samples if your vet has asked for them.