Which organism is a protozoal cause of chronic diarrhea?

• A. Giardia
• B. Histoplasma
• C. Feline Infectious Peritonitis
• D. Panacur

Answer: (A)

Protozoal causes of chronic diarrhea include Giardia, a flagellated single‑celled parasite that colonizes the small intestine. It attaches to the intestinal mucosa and disrupts absorption, leading to malabsorption and persistent loose stools. Transmission happens when cysts in contaminated water or food are ingested. In animals, Giardia often presents with chronic, greasy diarrhea and sometimes weight loss. Histoplasma is a fungus causing systemic disease, not a protozoan; Feline Infectious Peritonitis is due to a coronavirus; and Panacur is a deworming drug, not an organism. So Giardia is the protozoal cause.