Researchers from the US Centers for Disease Control and Prevention (CDC) and India’s National Centre for Disease Control said they have found that eating lychees, locally known as litchi, on an empty stomach was the reason behind a mysterious illness that caused the deaths of hundreds of children in the town of Muzaffarpur in Bihar, India.
Around May and June every year since 1995, large numbers of young children would start showing signs of fever. They’d have seizures and convulsions, before slipping in and out of consciousness.
In 2014, hundreds of children were admitted to hospital exhibiting symptoms of this illness, branded locally as “chamkikibimari,” or “tinsel disease.” Of 390 admitted for treatment, 122 died.
At one point, heat, humidity, malnourishment, the monsoon and pesticides have all been considered to be contributing factors to the illness, which was said to resemble the symptoms of encephalitis, a disease that causes inflammation of the brain.
The researchers compared test results of children who had developed the mysterious illness and children who had not.Analysis of blood and spinal fluid samples showed no signs of infection or exposure to chemicals and insecticides.
However, most of the children who had fallen ill had eaten lychee fruit recently. They were also six times more likely to have visited a fruit orchard in the last 24 hours, the study said.
Muzaffarpur, Bihar, is the largest lychee farming region in India.
According to the study, parents reported that children in the affected villages spent most of the day eating lychees from the surrounding orchards, often returning home in the evening “uninterested in eating a meal.”
The results said that children who fell ill were twice as likely to have skipped dinner, which, according to the researchers probably resulted in “night-time hypoglycemia”. When their blood sugar level dropped, the body would start to metabolize fatty acids to produce a necessary boost of glucose.
However, urine samples showed that two-thirds of the ill children showed evidence of exposure to toxins found in lychee seeds – found in higher levels in unripe fruits.In the presence of these toxins “glucose synthesis is severely impaired,” the study said, leading to dangerously low blood sugar and brain inflammation in the children.
The Indian government recently issued a statement advising children to “minimize litchi fruit consumption” in affected areas, and eat an evening meal during the “outbreak period.”
However, the researchers said there are still some questions surrounding the mystery. For example, while orchards surround many villages in the area, typically only one child in each village develops the illness. The report suggests it may be something to do with genetics.
“The synergistic combination of litchi consumption, a missed evening meal, and other potential factors such as poor nutritional status, eating a greater number of litchis, and as yet unidentified genetic differences might be needed to produce this illness,” the study said.
However, it added that similar outbreaks had been reported in other lychee cultivation areas in West Bengal, and also beyond India in parts of Vietnam and Bangladesh.
Previous research had focused on pesticides rather than the fruit itself, but “the findings of our investigations might help to shed light on the cause of illness in the Bangladesh and Vietnam outbreaks,” the study said.