Sea lions showing seizures and disorientation are associated with poisoning by which toxin?

• A. Saxitoxin
• B. Ciguatoxin
• C. Okadaic Acid
• D. Domoic Acid

Answer: (D)

Domoic acid is the neurotoxin produced by certain diatoms during harmful algal blooms. In sea lions, consuming contaminated prey leads to brain toxicity that manifests as seizures and disorientation, often with other neurologic signs like confusion and ataxia. The toxin acts as a glutamate receptor agonist, causing excitotoxic brain injury, with the hippocampus particularly affected. This pattern—seizures and disorientation from a neuroexcitation injury—is classic for domoic acid exposure seen in sea lions and linked to amnesic shellfish poisoning in humans. Other toxins cause different syndromes: saxitoxin produces rapid paralysis by blocking sodium channels; ciguatoxin can cause neurologic symptoms with hot/cold reversal and GI upset but not typically seizures; okadaic acid mainly causes diarrhea and related GI symptoms.