DISCUSSION 



65 



may not play a part in causing some of our idiopathic neuropathies such 

 as multiple sclerosis, the muscular dystrophies, and amyotrophic lateral 

 sclerosis. Interestingly enough, very recently a U.S. Public Health Service 

 team has reported 312 an extensive survey of amyotrophic lateral sclerosis 

 among the Chamorros of Guam and other islands of the Mariana group. 

 They made the study because the incidence of the disease there is 420 per 

 100,000 population, a rate 100 times higher than in the rest of the world; 

 at any one time, one per cent of the adults are affected, and eight to ten 

 per cent of adult deaths are produced by it. No cause was discovered, 

 except perhaps some tenuous genetic relationship to the Chamorro tribe. 

 The investigators have apparently given little consideration to the water 

 contacts or fish-eating habits of these people. It may be more than co- 

 incidence that epidemics of fish poisoning — likely due to toxic phyto- 

 plankton — have been particularly plentiful in the Marianas. That algae 

 have not been implicated in the nerve afflictions may be due to the difficulty 

 in demonstrating them, or simply to their not even having been considered. 



It is interesting, if hazardous, to speculate also on a possible algal role 

 in another neurologic disease — acute poliomyelitis. The viral etiology is 

 certainly proven beyond any doubt, yet the epidemiology is anything but 

 clear. Is it possible that a symbiotic virus-alga state exists, favoring viral 

 transport or even viral multiplaction ? The thought is suggested by the 

 fact that the highest incidence of poliomyelitis is during the warm summer 

 months, when algal blooms are most prolific; also, that infection occurs 

 frequently following swimming. In the latter case, the victim, besides 

 ingesting virus, might also decrease local tissue resistance by contact with 

 algal toxins. However, we are not yet prepared to suggest Chlorella 

 instead of monkey kidney as a medium for culturing polio virus! 



A more definite chronic entity is "swayback," 82 ' 83 the neurologic dis- 

 order seen in lambs fed on seaweed. Whether a toxin disturbing copper 

 metabolism resides in the seaweed itself, or whether it originates in con- 

 taminating microscopic algae, has not been established. Also worth con- 

 sidering are the hepatitis and cirrhosis seen in animals suffering from 

 "waterbloom" toxicity. Their occurrence raises the question of whether 

 all human hepatitis classified as "viral" is really so. Certainly these various 

 diseases indicate that much might be gained from studying the results of 

 controlled administration of toxic algae to animals. 



