Zamia staggers is a form of cycad toxicosis, a term for the fatal nervous disease affecting cattle where they browse on the leaves or fruit of cycads. It is characterised by irreversible paralysis of the hind legs because of the degeneration of the spinal cord. It is caused by a toxin, often called cycasin or macrozamin, a β-glycoside (the sugar of which is primeverose) of methylazoxymethanol (MAM), and which is found in all cycad genera. Following ingestion the sugar is removed by bacterial glycosidase in the gut, with the MAM being absorbed. The metabolized toxin produces tumours of the liver, kidney, intestine and brain after a latent period which may be a year or longer. The disease has been known in Australia since the 1860s and was the subject of a Queensland Government investigation during the 1890s.[1]
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