In June 2019, an outbreak of acute encephalitis syndrome (AES) occurred in Muzaffarpur and the adjoining districts in Bihar state of India resulting in deaths of more than 150 children, mainly due to hypoglycemia.

[12] The symptoms of AES include an acute onset of fever and associated clinical neurological manifestations such as mental confusion, disorientation, delirium, convulsions, or coma.

[12][13] Early symptoms include headaches and vomiting, along with sudden hypoglycemia (drops in blood sugar levels), but may lead to coma, brain dysfunctions, and inflammation of the heart and lungs.

[17][18] AES can be caused by different microorganisms including virus, bacteria, fungi, parasites and spirochetes, as well as chemicals and toxins.

Malnourished children lack a buffer stock of sugar as glycogen in the liver which puts them at higher risk of hypoglycemia.

A diet heavy on unripe lychee fruits without having an otherwise full meal later in the day may put malnourished children at risk of hypoglycemia.

[6][15][2][21][20] Others disputed the findings citing the unlikeliness of very large consumption of unripe lychee fruits, lack of cases in healthy, well-nourished children and many other pediatric illnesses causing hypoglycemia.

[4] The Chief Minister of Bihar Nitish Kumar announced an ex gratia payment of ₹4 lakh (US$4,600) to the next of the kin of the children who died from AES.

[7][27] The union minister of health Harsh Vardhan visited and announced the set-up of 100-bed pediatric ward at the SKMCH as well as five virology laboratories in Bihar.

[4][28] The Supreme Court ordered the Bihar government to file an affidavit to show the competence of medical facilities and other hygiene conditions in the state in the wake of the deaths.

[29] The National Human Rights Commission (NHRC) sent notices to the Ministry of Health and Family Welfare and the Bihar government over the deaths and asked for a report in four weeks.