What it is
Giardia live in the small intestine, attached to its lining. They leave the body in the faeces as hardy cysts, which stay infectious for a long time in damp places such as puddles, ponds and wet grass. A small number is enough to infect another dog, so the parasites spread easily wherever many dogs gather: boarding kennels, shelters, dog parks.
Attached to the lining, Giardia disturb the absorption of food and fat, and the gut responds with inflammation. Puppies and young dogs are hit hardest. The cysts are not shed all the time, so a single stool test is sometimes not enough and the vet may ask for several samples.
Pick up faeces straight away, in the garden as well as on walks. Don't let your dog drink from puddles. If your dog is ill, keep its bed, bowls and the fur around its bottom clean, because cysts can stay on them and the dog can become infected again.
Signs you may notice
- Diarrhoea that settles and returns
- Mucus in the stool
- Passes a lot of gas
- Losing weight
- Vomits now and then
The dog has diarrhoea, with stools that are soft, pale, greasy and foul-smelling, sometimes with mucus. The diarrhoea can settle and then return, and the dog may pass a lot of gas, vomit now and then and lose weight. Some infected dogs show no signs at all but still spread the parasites.
When to see a vet
Book a visit if the diarrhoea lasts more than a day or keeps coming back, and bring a fresh stool sample. If the dog is a puppy, is lethargic or has stopped drinking, have it seen promptly.
This is general information, not veterinary advice. For your own dog's health, tests and treatment, see a vet.