Microbiology HIV pt with malabsorption, fever, chronic diarrhea, with an acid-fast positive organism. What is the causative agent? A Giardia B Microsporidia C Isospora D E. histolytica 💡 Explanation HIV pt with malabsorption, fever, chronic diarrhea, with an acid-fast positive organism. What is the causative agent? ✓ Correct Answer: C. Isospora