# Giardia prevalence in North American domestic cats

> Developing situation record from CLSTR: https://clstr.news/situations/20261103-giardia-prevalence-in-north-american-domestic-cats
> Updated: 2026-11-03T21:58:51.000Z. Sources: 2. Developments: 2.

Research involving over 157,000 fecal samples from domestic cats in the United States and Canada has identified a significant presence of the Giardia duodenalis parasite. The study, published in PLOS One, found that 6.3% of tested animals had active infections, with a higher prevalence of 10.7% among kittens compared to 1.3% in older cats.

A critical finding of the research is that 18.5% of infected cats carry genetic groups A and B. Unlike the animal-specific group F, these groups pose a zoonotic risk to humans, potentially causing symptoms such as abdominal pain, nausea, and diarrhea. 

Health officials and veterinarians emphasize that many infected cats may remain asymptomatic while shedding the parasite. Recommendations for prevention include frequent handwashing, disinfecting areas affected by diarrhea, and regular fecal testing, particularly in households with vulnerable individuals.

## Timeline

### 2026-11-03: Cat health research highlights immunity benefits and parasite risks

New studies show that gentle petting can boost a cat's immunity against respiratory infections, while warning that 1 in 15 cats may carry Giardia, a parasite that can potentially infect humans.

2 sources. https://clstr.news/cluster/cat-health-research-highlights-immunity-benefits-and-parasite-risks

### 2026-10-24: Giardia parasite found in North American domestic cats

A study of 157,000 cat fecal samples in the US and Canada found that 6.3% of cats carry Giardia, with 18.5% of those carrying strains that can infect humans.

2 sources. https://clstr.news/cluster/giardia-parasite-found-in-north-american-domestic-cats

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Cite as: Giardia prevalence in North American domestic cats. CLSTR, https://clstr.news/situations/20261103-giardia-prevalence-in-north-american-domestic-cats