# Giardia prevalence in North American domestic cats

> Developing situation record from CLSTR: https://clstr.news/situations/giardia-prevalence-in-north-american-domestic-cats
> Updated: 2026-10-17T02:00:00.000Z. Sources: 7. Developments: 2.

Research published in the journal PLOS One has highlighted the prevalence of the protozoan parasite Giardia intestinalis (also referred to as Giardia duodenalis) in domestic cats across North America. A large-scale study involving over 157,000 stool samples from the United States and Canada found a detection rate of approximately 6.3 percent, or roughly one in every 16 cats.

The study identified a zoonotic risk, noting that approximately 18.5 percent of positive cases involved genetic assemblages (A or B) that have the potential to transmit infection to humans. Findings indicated that younger cats are more susceptible, with kittens showing a 10.7 percent infection rate compared to 1.3 percent in cats aged 10 years or older. Symptoms in both pets and humans can include diarrhea, abdominal pain, vomiting, and lethargy.

## Timeline

### 2026-10-17: Giardia parasite found in North American domestic cats poses zoonotic risk

A major study of 157,000 cat stool samples in the US and Canada found that 6.3% of domestic cats carry the Giardia duodenalis parasite, some of which have the potential to infect humans.

4 sources. https://clstr.news/cluster/giardia-parasite-found-in-north-american-domestic-cats-poses-zoonotic-risk

### 2026-10-10: Giardiasis infection risks in pets and humans

Giardiasis, an intestinal infection caused by the Giardia parasite, affects pets and can be transmitted to humans through contaminated water, food, or contact with infected feces.

3 sources. https://clstr.news/cluster/giardiasis-infection-risks-in-pets-and-humans

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Cite as: Giardia prevalence in North American domestic cats. CLSTR, https://clstr.news/situations/giardia-prevalence-in-north-american-domestic-cats