Eosinophilic meningo-encephalitis is caused by-
**Core Concept**
Eosinophilic meningo-encephalitis refers to a rare inflammatory condition affecting the brain and meninges, characterized by an abnormal accumulation of eosinophils. This condition can be caused by various factors, including parasitic infections, allergic reactions, and other underlying diseases.
**Why the Correct Answer is Right**
The correct answer is **Angiostrongylus cantonensis**, a type of nematode parasite that can cause eosinophilic meningo-encephalitis through its larvae. When ingested, the larvae migrate to the brain, leading to an inflammatory response and the accumulation of eosinophils. This condition is often seen in individuals who consume undercooked or raw snails, slugs, or other intermediate hosts of the parasite.
**Why Each Wrong Option is Incorrect**
**Option A:** Toxoplasma gondii is a protozoan parasite that can cause toxoplasmosis, which primarily affects the retina and other tissues, but is not typically associated with eosinophilic meningo-encephalitis.
**Option B:** Cryptococcus neoformans is a fungal pathogen that can cause cryptococcal meningitis, which is characterized by an accumulation of neutrophils and lymphocytes, not eosinophils.
**Option C:** Herpes simplex virus is a common cause of encephalitis, but it does not typically result in eosinophilic meningo-encephalitis.
**Clinical Pearl / High-Yield Fact**
Eosinophilic meningo-encephalitis should be considered in patients with a history of eating undercooked or raw snails, slugs, or other intermediate hosts of Angiostrongylus cantonensis, particularly those with symptoms of headache, fever, and altered mental status.
**Correct Answer:** A. Angiostrongylus cantonensis