The Island of the Colorblind

But why should a single disease present itself chiefly as lytico in one decade, and then predominantly as bodig the next? Did this have something to do with age? – bodig patients, by and large, were a decade older than those with lytico. Did it have something to do with dose – could it be that the most severely exposed patients had their motor neurons knocked out in the 1950s, producing an ALS-like syndrome; whereas those exposed to less of the agent (whatever it was) were then caught by the slower effects of this on the brain, which might cause parkinsonism or dementia? Would most patients with lytico, were they to survive long enough, go on to develop bodig years later? (This, of course, was an impossible question, because lytico in its acute form cuts short the course of life. But Tomasa, still alive after twenty-five years of lytico, showed not a trace of bodig.) All of these questions were posed – but none of them could be answered.

Kurland had always felt that the possibility of cycad toxicity, however odd it seemed, should be investigated as carefully as possible, and to this end, he had organized, with Whiting, a series of major conferences starting in 1963 and continuing for a decade. The first of these were full of excitement, hopes of a breakthrough, and brought together botanists, nutritionists, toxicologists, neurologists, pathologists, and anthropologists to present research from all over the world. One constituent of cycad seeds was cycasin, a glycoside which had been isolated in the 1950s, and this was now reported to have a remarkable range of toxic effects. Large doses caused death from acute liver failure; smaller doses might be tolerated by the liver, but later gave rise to a variety of cancers. While cycasin did not seem to be toxic to adult nerve cells, it was one of the most potent carcinogens known.

There was renewed excitement when another compound found in cycad seeds was isolated – an amino acid, beta-2V-methylamino-levoalanine (BMAA), very similar in structure to the neurotoxic amino acid beta-N-oxalylamino-levoalanine (BOAA), which was known to cause the paralysis of neuro-lathyrism. Was BMAA, then, the cause of lytico-bodig? It had been administered in many animal experiments, John said, but none of the animals developed anything like lytico-bodig.

Meanwhile there were two further discoveries of an epidemiological sort. In 1962 Carleton Gajdusek, who had been working on the cause of kuru, a fatal neurological disease in eastern New Guinea (work for which he was later awarded a Nobel Prize), now found an endemic lytico-bodig – like condition among the Auyu and Jakai people on the southern coastal plain of western New Guinea.[65] This proved indeed to be an extraordinarily ‘hot’ focus, for the incidence of disease here was more than 1,300 per 100,000, and thirty percent of those affected were under the age of thirty. At about the same time, in Japan, Kiyoshi Kimura and Yoshiro Yase discovered a third focus of a lytico-bodig – like disease on the Kii Peninsula of the island of Honshu. But in neither of these places did they find any cycads.

With these new findings, and the inability to produce an animal model of the disease, the plausibility of the cycad hypothesis seemed to fade. ‘The cycad proponents thought they had it,’ said John, somewhat wistfully. ‘They thought that they’d cracked the lytico-bodig, and it was a real loss to let the cycad hypothesis go. Especially as they had nothing to replace it; they were left with a sort of conceptual vacuum.’ By 1972 only Kurland continued to consider it a possibility, but for most of the researchers, the cycad hypothesis had died, and attention turned elsewhere.

John had arranged to take me that evening to a Japanese restaurant in Agana. With our huge tourist trade, he said, we get the best Japanese food in the world here, outside Japan. As we sat down and studied the enormous, exotic menus before us, I was interested to see fugu, puffer fish, listed; it was ten times as expensive as anything else on the menu.

‘Don’t try it!’ said John, adamantly. ‘You have a one in two hundred chance of being poisoned – the chefs are highly trained, but sometimes they make a mistake, leave a trace of skin or viscera on the fish. People like to play Russian roulette with the stuff, but I think there are better ways to die. Tetrodotoxin – a ghastly way to go!’