Acute Encephalitis Syndrome: Is Lychee Fruit the real Reason for Children Deaths?
Muzaffarpur in Bihar has been hit by curious cases of Acute encephalitis syndrome (AES) for the past few months. The cases that happened in Bihar’s Muzaffarpur, Vaishali, Sheohar districts have claimed more than 100 lives. Around 100 children have been admitted to various hospitals. The immediate reason behind the death has been attributed to Hypoglycaemia, i.e. low blood sugar level. Most of the cases have been reported from areas near Lychee orchards.
According to a study, it may be due to the eating of Lychee among malnourished children. Lychee contains chemicals and substances that are kind of similar to Ackee, a Jamaican fruit. This fruit is the main reason for childhood acute encephalopathy disease named Jamaican vomiting sickness (JVS).
What is AES?
AES is a common term to a condition affected to children with clinical neurological manifestations, which include mental confusion, disorientation, convulsion, or even coma. Meningitis caused by virus or bacteria, encephalitis caused by a virus, encephalopathy, cerebral malaria and scrub typhus caused by bacteria are collectively called acute encephalitis syndrome. Encephalopathy is biochemical in origin and is different from the rest. Even though there are different types of encephalopathy, in Muzaffarpur case, it is associated with hypoglycemia and hence called hypoglycaemic encephalopathy.
As per the study conducted by T Jacob John, virologist and pediatrician from Vellore and Mukul Das of Indian Toxicology Research, Lucknow, the clinical features of Ackee poisoning and Muzaffarpur AES are similar. The clinical features in these patients are stereotypical: Inconsistent presence of fever, brain oedema, absence of inflammatory cell response in cerebrospinal fluid and hypoglycemia, and sudden onset with prodromal phase. The clinical features and the preliminary epidemiological findings have supported that it may be due to acute non-infectious encephalopathy and not viral encephalitis. The children who are diagnosed with this condition are well and good till evening, but their condition worsens the next morning with brain function derangement and seizures. Malnutrition is considered as the main associated factor for kids affected by this condition.
Is Lychee seed the real villain?
Lychee seeds contain a lower analog of hypoglycin A, namely methylene cyclopropyl-glycine (MCPG)14. MCPG is not found in the ripe or unripe lychee fruit, but it’s found to cause hypoglycemia and derangement of fatty acid β-oxidation in liver cell mitochondria in experimental animals. As per reports, it is due to the toxicity of MCPG that has killed the children and this toxicity is due to the formation of MCPF-CoA, which in turn inhibits several dehydrogenases responsible for gluconeogenesis, causing depletion of glucose reserve in the body.
Usually, in the early morning, it is normal for the blood sugar to dip since there is no food intake for several hours. Malnourished children who had gone to sleep without a meal at night develop hypoglycaemia. The brain actually needs a normal level of glucose in the blood to function properly. And in this condition, the liver is unable to supply it and hence the alternate pathway of glucose synthesis (fatty acid oxidation) is turned on. This pathway is blocked by MCPG and ends up in death. The study says that in malnourished children, who had eaten lychee fruits the previous night on empty stomach, the situation proves fatal.
In another study done by Arun Shah of the Indian Academy of Paediatrics and appeared in Lancet Global Health journal in 2017, the children in the affected villages fell ill the next morning after eating them the previous night with symptoms like high fever, brain function derangement, and seizures. The doctors also say that the disease can be treated through an infusion of dextrose within four hours of the onset of the illness. Another technique is to ensure that no child goes to bed without a meal. The Lancet report had suggested the Bihar Government to keep children away from orchard gardens during April-June and also urged ministers to tackle the malnutrition in the various families.