Zealand's native Puha contains 1080 in very low concentrations. Toxicology Sodium fluoroacetate is toxic to all obligate aerobic organisms, and highly toxic to mammals and insects. The oral dose of sodium fluoroacetate sufficient to be lethal in humans is 2–10 mg/kg. The toxicity varies with species. The New Zealand Food Safety Authority established lethal doses for a number of species. Dogs, cats, and pigs appear to be most susceptible to poisoning. The enzyme fluoroacetate dehalogenase has been discovered in a soil bacterium, which can detoxify fluoroacetate in the surrounding medium. Mechanism of action Fluoroacetate is structurally similar to acetate, which has a pivotal role in cellular metabolism. This similarity is the basis of the toxicity of fluoroacetate. Two related mechanisms for its toxicity have been discussed, with both beginning with the conversion of fluoroacetate to 2-fluorocitrate. 2-Fluorocitrate arises by condensation with oxaloacetate with fluoroacetyl coenzyme A, catalyzed by citrate synthase. Fluorocitrate binds very tightly to aconitase, thereby halting the citric acid cycle. This inhibition results in an accumulation of citrate in the blood. Citrate and fluorocitrate are allosteric inhibitors of phosphofructokinase-1 (PFK-1), a key enzyme in glycolysis. When PFK-1 is inhibited, cells are no longer able to metabolize carbohydrates, depriving them of energy. Alternatively, fluorocitrate interferes with citrate transport in the mitochondria. Symptoms In humans, the symptoms of poisoning normally appear between 30 minutes and three hours after exposure. Initial symptoms typically include nausea, vomiting, and abdominal pain; sweating, confusion, and agitation follow. In significant poisoning, cardiac abnormalities including tachycardia or bradycardia, hypotension, and ECG changes develop. Neurological effects include muscle twitching and seizures; consciousness becomes progressively impaired after a few hours leading to coma. Death is normally due to ventricular arrhythmias, progressive hypotension unresponsive to treatment, and aspiration pneumonia. Symptoms in domestic animals vary: dogs tend to show nervous system signs such as convulsions, vocalization, and uncontrollable running, while large herbivores such as cattle and sheep more predominantly show cardiac signs. Sub-lethal doses of sodium fluoroacetate may cause damage to tissues with high energy needs — in particular, the brain, gonads, heart, lungs, and fetus. Sub-lethal doses are typically completely metabolised and excreted within four days. Treatment Effective antidotes are unknown. Research in monkeys has shown that the use of glyceryl monoacetate can prevent problems if given after ingestion of sodium fluoroacetate, and this therapy has been tested in domestic animals with some positive results. In theory, glyceryl monoacetate