Gastrointestinal (GI) parasitism is a common problem in cats, with prevalence rates as high as 45% in some populations. These parasites can be wormlike or one-celled protozoan organisms.
They usually cause fairly nonspecific symptoms, such as a dull coat, coughing, vomiting, diarrhea, mucousy or bloody feces, loss of appetite, pale mucous membranes, or a potbellied appearance.
The vomiting, diarrhea, anemia, and dehydration caused by intestinal parasites can weaken a cat, making it more susceptible to viral and bacterial infections and other diseases. Importantly, some GI parasites of cats have the potential to infect humans.