It is always better to err on the side of caution. Giardia in Cats Giardiasis is an intestinal infection of man and animals. It is caused by a protozoal parasite called Giardia intestinalis . Giardiasis is an important cause of illness in animals and man. Fortunately, even though the infection rate is high in cats and dogs, clinical disease is less common.
Infection is relatively rare in healthy cats.
It is more common in densely-populated groups of animals, such as in a cattery, pet store, or animal shelter. Also, kittens have been shown to shed more Giardia cysts in their feces than older cats. The stool may range from soft to watery, and occasionally contains blood. Infected cats tend to have excess mucus in the feces. Sometimes, vomiting can occur.