In a patient, corneal scraping reveals narrow angled septate hyphae, which of the following is likely etiologic agent –
**Core Concept**
The question is testing the student's ability to identify a specific fungal pathogen based on its microscopic characteristics. Narrow angled septate hyphae are a distinctive feature of certain fungi, which can be used to differentiate them from other pathogens.
**Why the Correct Answer is Right**
The correct answer is likely *Aspergillus*, which is a common cause of fungal keratitis (corneal infection). The narrow angled septate hyphae described in the question are consistent with the microscopic appearance of *Aspergillus*. This fungus produces septate hyphae that branch at narrow angles, which is a key feature for its identification.
**Why Each Wrong Option is Incorrect**
* **Option A:** Not specified - This option is incomplete and cannot be evaluated.
* **Option B:** Fusarium - While Fusarium can cause fungal keratitis, it typically produces non-septate or irregularly septate hyphae, which is different from the narrow angled septate hyphae described in the question.
* **Option C:** Mucor - Mucor produces non-septate or poorly septate hyphae, which is not consistent with the description in the question.
**Clinical Pearl / High-Yield Fact**
Fungal keratitis is a serious infection that can lead to vision loss if not treated promptly. The diagnosis is often made by corneal scraping and microscopic examination, which can reveal the characteristic hyphae of the causative fungus.
**Correct Answer:** C. Aspergillus.