- In India, Acute Encephalitis Syndrome outbreaks in the north and eastern India have been linked to children eating unripe litchi fruit on empty stomachs.
- Unripe fruit contains the toxins hypoglycin A and methylenecyclopropylglycine (MCPG), which cause vomiting if ingested in large quantities.
- Hypoglycin A is a naturally occurring amino acid found in the unripened litchi that causes severe vomiting (Jamaican vomiting sickness), while MCPG is a poisonous compound found in litchi seeds that causes a sudden drop in blood sugar, vomiting, altered mental states leading to lethargy, unconsciousness, coma, and death.
- These toxins cause sudden high fever and seizures serious enough to require hospitalization in young, severely malnourished children
The AES cases in Muzaffarpur, Bihar, and adjoining litchi producing districts have been observed mostly from April to June, particularly in children who are undernourished with a history of visiting litchi orchards. Relationship between consumption of litchi and AES was postulated by National Centre for Disease Control, Delhi (along with Centre for Disease Control US) in acute encephalitis in children, in Muzaffarpur.
Other causative agents for AES are
- JE virus
- Herpes simplex virus
- Nipah virus
- Zika virus
- Influenza A virus
- West Nile virus
- Chandipura virus
- scrub typhus
- Streptococcus Pneumonia