A pregnant lady with aids complains of diahorrea and stool examination shows acid fast positive cysts. She has infection with:
**Core Concept**
The question is testing the student's knowledge of opportunistic infections in immunocompromised patients, particularly those with AIDS. The presence of acid-fast positive cysts in stool suggests an intestinal infection caused by a protozoan parasite.
**Why the Correct Answer is Right**
The correct answer is a protozoan parasite that infects the intestinal mucosa and causes diarrhea. The parasite's acid-fast positive cysts are a key diagnostic feature. In immunocompromised patients like those with AIDS, the parasite can cause severe and persistent diarrhea, leading to malabsorption and weight loss.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a type of bacterial infection that causes diarrhea, not a protozoan parasite.
**Option B:** This option is incorrect because it is a type of fungal infection that can cause opportunistic infections in immunocompromised patients, but it does not cause acid-fast positive cysts in stool.
**Option D:** This option is incorrect because it is a type of viral infection that can cause diarrhea, but it is not a protozoan parasite and does not cause acid-fast positive cysts in stool.
**Clinical Pearl / High-Yield Fact**
In immunocompromised patients, opportunistic infections like protozoan parasites can cause severe and persistent diarrhea, leading to malabsorption and weight loss. Always consider the possibility of an opportunistic infection in patients with unexplained diarrhea and a history of immunosuppression.
**Correct Answer:** C. Cryptosporidium. Cryptosporidium is a protozoan parasite that causes intestinal infection and diarrhea, especially in immunocompromised patients.