For more than 20 years, scientists have puzzled over the cause of the illness, whereby apparently healthy children have been losing consciousness after suffering seizures. Roughly half of the children went on to die.
Now American and Indian scientists believe they understand the cause of the epidemic in Muzaffarpur, India’s main lychee growing area, after a three-year study.
Their hospital-based research assessed children aged under 15 who were admitted to two hospitals in the district over three months in 2014 with new-onset seizures or altered sensorium.
Most of the victims were poor and had eaten fruit that had fallen onto the ground in orchards.
The researchers took clinical specimens from the children, while locally produced lychees were tested for evidence of infectious pathogens, pesticides, toxic metals and other non-infectious causes.
They also found a link to an outbreak of sickness that caused brain swelling and convulsions in children in the Caribbean.
That outbreak was caused by ackee fruit which contained hypoglycin, a toxin that prevents the body from making glucose. Tests then showed that lychees also contained hypoglycin, as well as methylenecyclopropylglycine (MCPG), another natural, fruit-based toxin.
They found that the toxins affected young children whose blood sugar levels were already low because they lacked a balanced diet.
“Our investigation suggests an outbreak of acute encephalopathy in Muzaffarpur associated with both hypoglycin A and MCPG toxicity,” the scientists have revealed in The Lancet this month.
The findings prompted health officials to warn parents not to allow their children to eat lychees on an empty stomach. They also recommended rapid treatment for hypoglycaemia for children displaying symptoms.
The number of reported cases of the sickness has since fallen from hundreds each year to about 50, the New York Times has reported.
More from South Asia…
FSSAI moves to regulate organic traceability
India’s food regulator will clamp down on the traceability organic foods with new standards to ensure the organic status of product claims.
The Food Safety and Standards Authority of India (FSSAI) has proposed that traceability should be established at producer level. It will now seek a public review of the draft regulation before it can be finalised.
The proposal also specifies labelling and certification standards. “Such products shall carry a certification/quality assurance mark of one of the systems that certify organic food.
“Any seller of organic food either exclusively or as part of their retail merchandise shall display such food in a manner distinguishable from... conventional food so that the consumers are not misled,” the draft regulations added.
Non-compliance will incur penalties as a “false, misleading or deceptive claim”.
“The food authority may establish appropriate institutional mechanisms to implement these regulations and promote authentic organic food in the country,” the draft added.