icddr,b study links sudden deaths in Bangladeshi children to chemicals sprayed on fruit trees

25 JUL 2017

A new icddr,b study finds evidence of using powerful insecticides, including one banned in 80 countries, in local fruit orchards in Bangladesh where many victims often played.

Lychee is cultivated across China and South Asia. Photo: SimonQ. CC BY-NC-ND 2.0

Published in the American Journal of Tropical Medicine and Hygiene, the study findings suggest that use of these insecticides may have triggered an outbreak of acute encephalitis syndrome (AES), a condition often associated with deadly inflammation of the brain, that killed 13 children in a rural Bangladesh community in 2012.

All of the deaths, which occurred within 20 hours of the onset of symptoms, were linked to exposure to lychee, a small, reddish fruit with a sweet white flesh that is cultivated across China and South Asia.

Similar deaths from AES have been observed near lychee orchards in India; however, a recent analysis published in the journal The Lancet concluded that those deaths were caused by a reaction to a naturally occurring toxin found in lychee seeds and pulp.

"Our investigation suggested the seeds might not be the cause as the seeds are not eaten in Bangladesh and instead found the deaths in 2012 were most likely due to an exposure to multiple, highly toxic agrochemicals," said M Saiful Islam, associate scientist at icddr,b and lead author of the study.

"These deaths occurred at a time when lychee was being harvested and consumed across Bangladesh. If the seeds were the cause, then we would expect to see cases scattered across the country, not just in a certain small area," he added.

Islam and colleagues from icddr,b, the Institute of Epidemiology, Disease Control and Research (IEDCR) and the United States Centers for Disease Control and Prevention (CDC) based their conclusion on an exhaustive investigation into 14 cases of AES in children 1 to 12 years old that occurred between May 31 and June 30, 2012 in the Dinajpur District in northern Bangladesh. Only one child survived.

The scientists discovered that around the time of the 2012 outbreak, growers were applying endosulfan in the orchards, which, the study notes, is a "highly toxic" insecticide that has been banned due to the deleterious health effects in more than 80 countries. As of 2016, Bangladesh was one of several countries, including the United States, that still allowed restricted use of endosulfan. The pesticide was slated to be phased out of use in the United States by the end of 2016.

According to the study, 13 of the 14 children lived either right beside or within 10 meters of a lychee orchard. One victim did not live as close to an orchard, but, before falling ill, he reportedly consumed a large number of lychees collected from the same orchards.

Repurposed with permission from ASTMH. For the full report, read the official press release.