B ABBOTT 



as having three components: the agent, the host population, and the 

 environment. In other words, multiple factors inevitably enter into 

 causation. The task of the epidemiologist is to determine the nature 

 and relative importance of these factors, so that we may know where 

 to apply control measures most effectively. 



I would like to talk briefly and in very general terms about some 

 aspects of these three components of mass disease as they relate to 

 the Arctic, and we might begin with a consideration of infectious 

 agents. The first point to be made is that very few human pathogens 

 are strictly localized to arctic areas,Ofcourse,northern populations 

 have been studied less intensively than residents of other regions, 

 and yet I doubt if a totally new bacterium or virus having man as its 

 primary host will be isolated from these people. The same cannot 

 be said with equal confidence for parasites, however, because their 

 life cycles sometimes include intermediate hosts unique to northern 

 latitudes. The second point I'd like to make is that the variety of 

 infectious agents thus far encountered in the Arctic is limited, at 

 least by temperate and tropical standards. This is hardly unexpected, 

 since the same observation applies to arctic flora and fauna gener- 

 ally (Polunin, 1955; Bliss, 1962). 



During our intestinal disease studies in Alaska, Greenland, and 

 Lapland, some 4,200 people were examined bacteriologically. Only 

 four types of shigella and five types of salmonella were identified, 

 and all were familiar pathogens. The greatest variety came from a 

 couple of Alaskan villagepopulations which included only 325 people. 

 Among nearly 2,000 well Greenlanders surveyed, the sole pathogenic 

 bacteria found were Sh. sonnei in three carriers and S. paratyhi B 

 harbored by four others (Gordon, 19 59). Except for one trematode, 

 Cryptocotyle lingua, the parasites identified in stools of 660 

 West Greenlanders were well recognized inhabitants of the human 

 gastrointestinal tract. These included E, coli, Endolimax nana, 

 Gardia lambia, Chilomastix, and, surprisingly enough. Entamoeba 

 histolytica in some 16 per cent (Babbott, 1961). 



Hildes and his colleagues (Hildes, 19 58, 19 59) have carried out 

 serologic surveys in the Canadian Arctic, and Dr. Reinhard will 

 speak shortly about similar work here in Alaska. The agents they 

 identified - poliomyelitis, Coxsackievirus, psittacosis, ECHOvirus, 



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