The pesticides blamed for killing at least 25 children in India are widely used around the world and health experts have raised safety concerns about this class of chemicals in the past also.
Known as organophosphates, the pesticides were developed in Germany in the 1940s and soon became an important defense against agricultural pests.
They are extremely toxic.
The Indian children, aged four to 12, fell ill on Tuesday after eating a lunch consisting of rice, soybeans, and lentils in the village of Mashrakh in the eastern state of Bihar.
The school that the children attended provided free meals under a nationwide program known as the Mid-Day Meal Scheme. Early reports suggest the food—perhaps the rice or the cooking oil used to prepare the food—contained unsafe levels of the pesticide.
Upon entering the body—through ingestion, inhalation, or contact with skin—organophosphates inhibit cholinesterase, an enzyme in the human nervous system that breaks down acetylcholine, a neurotransmitter that carries signals between nerves and muscles.
When cholinesterase is inactivated, acetylcholine builds up in the nerves, which become overactive. Victims of organophosphate poisoning typically die because they can’t breathe.
“It’s a painful way to die,” Boyd Barr said. “You end up suffocating because you are essentially paralyzed.”
The risk of death depends on the amount of exposure and the age of the victim. The symptoms tend to be more severe in young children.
“They’re more vulnerable because their detoxification systems are more immature, so they can’t eliminate the pesticide as well,” Boyd Barr explained.
Doctors typically treat organophosphate poisoning with atropine to alleviate the symptoms and help the patient feel better, and oxine to help replenish the body’s store of cholinesterase.
Small Amounts Tolerated
In the United States, a small amount of organophosphates on crops after harvesting is tolerated and farmers take care to ensure that the amounts don’t reach dangerously high levels.
But in countries such as India, where regulations may not be as strict or the implementation and enforcement of regulations are not as effective, the likelihood of organophosphate poisoning through the contamination of food can be higher, Boyd Barr said.
The Indian school case is not the first instance of organophosphate poisoning: In 1986, more than 20 people in Sierra Leone, many of them children, died after eating bread made with flour that was transported in a truck that was previously used to carry organophosphates.
While high-level exposure to organophosphates can lead to death in the short term, several studies have suggested that chronic low-level exposure can also have serious health consequences, especially for infants and young children.
Source(s): Nat Geo