everything you need to know about Giardia.

Giardia is an internal parasite which affects the intestines in both humans and animals. Several dogs come into the Urban Vet with symptoms every week, and around half are positive. Dogs can become infected with Giardia when they swallow the cyst of the parasite. In susceptible individuals, the egg-like cyst travels to the intestines where it matures and attaches to the intestinal wall to feed. When large numbers of Giardia have infiltrated the intestinal wall, damage occurs leading to the clinical signs we see. 

Between 5-12 days after ingestion of the parasite, dogs will start to pass eggs in their stool (between 5-16 days for cats). Giardia is transmitted by ingesting or inhaling infectious cysts from the contaminated ground or from drinking contaminated water. 

We test for Giardia by looking for evidence of the parasite in your animal’s stool either by a faecal examination or an in-house SNAP test. If present Giardia can cause severe watery diarrhoea which can become fatal if untreated. 

Clinical Signs:

The damage caused to the intestinal wall causes an acute, foul-smelling watery diarrhoea. Giardia infection can also lead to weight loss, chronic intermittent diarrhoea, and fatty stools (faeces with a shiny/oily-looking surface). Occasionally the stool can contain blood and excess mucus. In some animals, we can also see vomiting and reduced appetite. If the clinical signs persist for a few weeks, they can cause gradual weight loss.

Diagnosing Giardia:

If we suspect your animal may have Giardia, we will use a SNAP Giardia test to look for antigens in your animal’s faeces. This SNAP test is done in-house and can be used for dogs and cats. The test result takes about 8-10 minutes to develop and then will determine if the Giardia antigen is present. 

Treatment of Giardia:

The drug we use to treat Giardia is called Fenbendazole (an anti-parasitic). It is sold under trade names such as Panacur or Safeguard. We can also use a supportive treatment such as intravenous fluids and probiotics to help your animal with dehydration and diarrhoea. 

Looking after your dog with Giardia:
If your dog gets infected with Giardia, we recommend cleaning around their rear end and hindquarters with soap and water to minimise reinfection. In order to prevent the spread to other dogs, it is also vital to ensure as much of your dog’s stool is picked up from the environment. As Giardia can be passed onto humans, it is very important to wash your hands after cleaning up your dog’s stool or diarrhoea to protect yourself.