Which statement is true about pesticide toxicity?

• A. Pesticide toxicity is always immediate.
• B. Only organochlorine pesticides cause acute toxicity.
• C. Cholinesterase inhibition due to exposure to organophosphate or carbamate insecticides can cause acute or delayed effects.
• D. Toxicity is unaffected by exposure routes.

Answer: (C)

The main concept here is that pesticide toxicity from organophosphate and carbamate insecticides comes from blocking acetylcholinesterase, the enzyme that breaks down acetylcholine in nerve synapses. When this enzyme is inhibited, acetylcholine builds up and continuously stimulates both muscarinic and nicotinic receptors, leading to a range of acute cholinergic signs such as sweating, tearing, salivation, diarrhea, vomiting, pinpoint pupils, bronchoconstriction, slowed heart rate, muscle twitching, and in severe cases seizures or respiratory failure. Some organophosphates can also cause a delayed neuropathy weeks after exposure, due to damage to nerves, whereas carbamates typically produce reversible, shorter-lived acute effects and rarely cause this delayed neuropathy. So the statement is true because cholinesterase inhibition from these pesticides can produce immediate toxicity and, in certain organophosphate exposures, delayed effects. Toxicity isn’t always immediate, and it isn’t limited to organochlorines, and the route of exposure does affect how quickly symptoms appear.