nutritionally inadequate. Thus, while malnutrition is most prevalent 

 in poor countries, it is by no means absent in rich nations, even among 

 the most affluent of the population. 



Although remote from current experience in our own country, 

 the problems of parasitic infestation remain large in many parts of the 

 world. Schistosomiasis claims millions of lives annually and debilitates 

 many more; no effective means of control is yet in use. Malaria 

 remains a major health problem despite spectacular gains. The 

 primary method of controlling this disease at present involves the use 

 of pesticides, chiefly DDT. Although use of DDT on the scale required 

 to combat malaria may not represent a serious environmental hazard, 

 other means of control that are inexpensive and ecologically safe are 

 needed. These are only two of the many parasite-induced diseases 

 found in much of the developing-world. 



In more affluent nations the problems of malnutrition and 

 parasitic infection are diminishing, along with numerous other 

 classical afflictions, endocrine disorders, most bacterial infections, 

 some insect-borne diseases, and those viral diseases now preventable 

 by immunization. These achievements have come from advances in 

 the biological sciences over the last few decades. In the place of these 

 diseases, man is now confronted with two general categories of major 

 afflictions: those loosely classed as degenerative disorders, including 

 cancer, and those of genetic origin. Degenerative disorders now 

 dominate medical practice in much of the developed world. They 

 account for the bulk of the $80 million of annual expenditure for 

 health care in the United States, much of which goes for "halfway 

 medical technologies" capable of managing the diseases to some 

 extent, but not of preventing or curing them. 



The second general category of disease — diseases of genetic 

 origin — are now growing in relative importance. Three decades ago, 

 only a dozen or so genetic disorders had been identified; today the list 

 is nearer to a thousand, including some 150 diseases in which the 

 specific nature of the genetic defect is known. The identification of 

 these many genetic disorders was made possible by advances in 

 scientific and medical knowledge. Now that they have been identified, 

 means for treating them must be sought. This illustrates how 

 advances in scientific understanding lead to rising expectations and 

 aspirations. 



At present, nongenetic therapy is the most common mode of 

 treating these diseases, an approach which results in the further 

 dissemination of the defective genes in the population at large. 

 Diabetes is a case in point. Before the advent of insulin, juvenile 

 diabetics seldom lived long enough to reproduce, but since insulin 

 therapy became available 50 years ago, many survive and reproduce, 

 thereby transmitting the defective genes and increasing the incidence 

 of diabetes. If similar approaches are used for other genetic disorders 



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