A new study has revealed that the innocent-looking lychee fruit is responsible for killing more than 100 children in India annually for the past 22 years.

The study, published in the medical journal The Lancet Global Health, showed that the mystery illness terrorizing children in the town of Muzaffarpur in Bihar, India was caused by a certain toxic found in lychees.

"It was an unexplained illness for so many years," said Padmini Srikantiah, a senior epidemiologist with the C.D.C. and the senior author of the paper, in a report from New York Times. "This is kind of emblematic of why we collaborate, to build this kind of systematic approach."

For the study, researchers from India's National Center for Disease Control were joined by investigators from the India office of the Centers for Disease Control and Prevention in Atlanta. The two organizations conducted a joint investigation regarding the mysterious illness that sickened 390 children, including 122 that died, in 2014.

After two years of thorough investigations, the researchers found some clues that point the lychee fruit as the main culprit of the disease outbreak. They noted that the blood and spinal fluid samples from the patients showed no signs of infection. However, some of the affected children presented low blood sugar.

Low blood sugar, brain swelling and convulsions were the same symptoms experienced by people afflicted by the so-called "Jamaican vomiting sickness." Due to this, the researchers found a possible link between the outbreak that occurred in the West Indies and the one that is currently being faced by the children in Bihar.

The Jamaican vomiting sickness is caused a toxin called hypoglycin. Found in the ackee fruit, hypoglycin is capable of inhibiting the body's ability to synthesize glucose. Laboratory tests conducted in 2014 confirmed that lychees also contain high levels of hypoglycin, as well as a similar toxin called methylenecyclopropyl glycine or MCPG.

With their findings, the researchers recommended that children should reduce their consumption of lychees. Furthermore, the researchers also advised parents to make sure that their children eat their evening meal.