Research Highlight

Litchi fruits behind mystery seasonal deaths

doi:10.1038/nindia.2017.15 Published online 1 February 2017

The litchi fruit
Researchers have found a link between the mysterious seasonal deaths of children in Muzzafarpur region of Bihar and consumption of litchi fruits laden with the naturally occurring toxins hypoglycin A and methylenecyclopropylglycine (MCPG)1. The study supports a growing body of evidence from other litchi growing regions of the world as well as previous reports from India2-5.

The researchers say this is the first study of the metabolites of these toxins in human biological specimens, the biological impact of these toxins on human metabolism, and the modifying effect of the lack of an evening meal on the impact of these toxins.

A group of researchers from India's National Centre for Disease Control and the US Centers for Disease Control and Prevention studied the outbreaks of an unexplained acute neurological illness that kills children every year since 1995 in Muzaffarpur, India's largest litchi cultivation region. They conducted a hospital-based surveillance and laboratory investigations to figure out the potential infectious and non-infectious causes of this mystery ailment.

They tested the litchis for infectious pathogens, pesticides, toxic metals, and other non-infectious causes, including presence of hypoglycin A or MCPG, fruit-based toxins that cause hypoglycaemia and metabolic derangement. Their investigation on 390 patients admitted to local hospitals in 2014 suggested that the outbreak of acute encephalopathy was due to both hypoglycin A and MCPG toxicity.

In order to reduce the deaths due to the outbreaks, the researchers recommend minimising litchi consumption, ensuring an evening meal to children and correcting the glucose levels of patients urgently after they report with the illness.

References

1. Shrivastava, A. et al. Association of acute toxic encephalopathy with litchi consumption in an outbreak in Muzaffarpur, India, 2014: a case-control study. Lancet Glob. Hlth. (2017) doi: 10.1016/S2214-109X(17)30035-9

2. Islam, S. Outbreak of illness and deaths among children living near lychee orchards in northern Bangladesh. Hlth. Sci Bull. 10, 15-21 (2012)

3. Paireau, J. et al. Litchi-associated acute encephalitis in children, northern Vietnam, 2004–2009. Emerg. Infect. Dis. 18, 1817–1822 (2012)

4. John, T. J. & Das, M. Acute encephalitis syndrome in children in Muzaffarpur: hypothesis of toxic origin. Curr. Sci. 106, 1184–1185 (2014)

5. Spencer, P. S. et al. Probable toxic cause for suspected lychee-linked viral encephalitis. CDC Emerg. Inf. Dis. 18, 904–905 (2015)