p The data on the structure of mortality causes in some measure reflect the situation with regard to disease incidence, i.e., the prevalence of various diseases among the population as a whole or in its different groups.

p In view of the difficulties of taking stock of all disease incidence we shall confine ourselves to some information on general disease incidence. Compared with 1926-28, when mass investigations into the general disease incidence were carried out, this highly significant and most important index of the state of the people’s health has now decreased by more than 50 per cent. Obviously, the most important reason for this reduction was a sharp decrease in the occurrence of infectious and parasitic diseases which were the main causes of death in the not so distant past. The decrease in the prevalence of infectious diseases, and especially those which were responsible for extensive early mortality among children, is evidenced by the following few figures: in 1966, as compared to 1940 the mortality rate among urban children under one year of age went down in the case of diphtheria by 402 times, in the case of scarlet fever by 347 times, Table 4 Infectious Diseases Incidence (per 100,000 population) in 1940-68 Disease 1940 I960 1965 1966 1967 1968 Typhoid fever and paratyphoids A_1? B_x and C 62 22 11 12 10 10 Scarlet fever 129 313 230 297 254 211 Diphtheria 91 25 2 1.3 1.1 0.9 Whooping cough 232 259 82 63 49 50 Tetanus 1.1 0.6 0.6 0.5 0.4 Poliomyelitis (acute) ’ 0 . 7 3.3 0.13 0.12 0.06 0.05 Measles 605 972 923 750 769 664 Infectious hepatitis (Botkin’s disease) 239 204 00 158 156 Epidemic typhus (in- cluding Brill’s disease) 25 2.9 1.6 1.5 1.4 1.3 Malaria 1,637 0.17 0.14 0.13 0.11 0.4 38 whooping cough—139 times, tuberculosis—77 times, measles—70 times, toxic dyspepsia, gastroenteritis and colitis— 38 times, dysentery—20 times and pneumonia—-7 times. An idea of the disease incidence is furnished by Table 4.

p Considerable success in wiping out a number of widespread and acutely contagious diseases was achieved in the USSR because of social-economic and medical reforms. As late as 1922 more than 76,000 cases of smallpox were recorded on the territory of the USSR. By 1936 smallpox had been eradicated through compulsory vaccination, begun after the Government had issued a special decree in 1919. Close to 1,400,000 cases of typhus were recorded on the territory of the USSR in 1922, whereas in 1940 there were only occasional cases of the disease. In 1940 the incidence of typhoid fever decreased to less than one-third of its 1922 level. Besides smallpox, other serious diseases such as plague and relapsing fever have been wiped out. Control of malaria in the Soviet Union was an outstanding achievement; no less significant was the practical eradication of trachoma in the RSFSR and many other parts of the country.

p The incidence of diphtheria and other infectious children’s diseases has decreased sharply in recent years; poliomyelitis, which was still very dangerous in the 1950s, has now been almost completely controlled. Only 120 cases of this disease were recorded in 1968. The following figures may give some idea of the fast rate of decrease of the incidence of infectious diseases in the USSR: in 6 years since 1960 the incidence of poliomyelitis decreased by 98 per cent, of diphtheria, by 97 per cent, of tularemia (which had gone down to 0.1 per cent of the 1940 level) by another 76 per cent, of tetanus, by 52 per cent and of brucellosis, by 61.5 per cent, etc.

p Viral diseases, especially influenza, are still widespread. Influenza, angina and other catarrhal diseases come high on the list of disease incidence in the USSR, as they do in many economically developed countries. In this respect the structure of disease incidence does not coincide with that of mortality where, as was noted above, the major part is played by nonepidemic diseases.

p In the Soviet Union the general disease incidence is studied mainly by means of an analysis of the people’s requests for treatment at medical institutions. Most of these calls, it has been shown, are connected with influenza, angina 39 and upper respiratory catarrh. These disorders hold first place in the structure of general disease incidence in the Soviet Union. They are followed by various traumas. Next in importance in the structure of general disease incidence, are ear, nose and throat diseases, especially chronic otitides, gastrointestinal diseases (gastritides, colitides, gastric and duodenal ulcers) and eye diseases (primarily conjunctivitides). After these come various cardiovascular disorders. The above diseases usually account for 70-80 per cent of the general disease incidence.

p The foregoing list indicates the approximate succession in the prevalence of diseases revealed mainly by the requests for treatment at medical institutions. According to specialists who study the prevalence of diseases among different groups of the population, a somewhat different pattern of diseases is observed among the people living in the countryside. For example, an extensive study of the disease incidence among the rural population carried out by workers of the All-Union Research Institute of Social Hygiene and Public Health Organisation, has shown influenza, catarrh, angina and a number of other disorders, mainly of an infectious character to be on top of the list in the countryside. The second place is held by diseases of the digestive organs, oral cavity and teeth, the third place, by diseases of the heart and blood vessels, the fourth, by traumas and the fifth, by respiratory diseases.

p Naturally, people do not always seek medical aid, especially in cases of chronic disease; to reveal these cases, researchers have to resort to such methods as the examination of groups of the population by teams of specialists and the careful study of each case by experts. Such examinations lead to the detection of quite a large number of disorders which require medical aid. For example, a study conducted under the supervision of Professor I. D. Bogatyryov revealed 500 cases of protracted diseases per ] ,000 of population, a figure amounting to one-third of all the people’s requests for medical aid at medical institutions. It follows that all recorded cases of disease may be figuratively compared with an iceberg, its above-water part being the cases of disease revealed when the people request help at medical institutions and its under-water part being the diseases, mainly chronic for which people do not ask for medical aid. The task of the researcher is to study the whole 40 iceberg, in order to reveal genuine picture of the people’s health.

p According to reports of Soviet statisticians, the general disease incidence of different groups of the population ranges from 1,100 to 1,400 cases per 1,000 population in a year. In analysing these seemingly high figures we must take into account the fact that with the development of the public health services the number of recorded diseases increases. This may result in an erroneous impression of an increasing rate of disease incidence. Actually, however, the incidence of disease in the USSR, especially that of infectious and parasitic diseases, has considerably decreased compared with the 1920s.

p And, although studies of the general incidence of disease are still the most complex and difficult part of medical statistics, on the basis of several random studies, we may judge of the generally high incidence of disease in capitalist countries. For example, according to official figures published in the USA,  [40•*  223 cases of acute diseases were recorded per 100 population in 1962, more than two-thirds of these cases having an infectious character (infectious and parasitic diseases, influenza, upper respiratory catarrh, etc.). One extensive random study conducted in the USA (in 1961-1962) revealed a large figure—401,851,000 cases of disease in a year, of which 49,123,000 cases was of infectious and parasitic diseases, and 230,805,000 of upper respiratory diseases, including influenza.  [40•** 

p One of the most important problems of public health services in many economically developed capitalist countries are mental diseases which show a distinct upward trend. In the USA mental health is now considered problem No. 1 of public health. The incidence of mental diseases (all cases, including those newly recorded) in most capitalist countries has been estimated by a number of prominent authorities at between 40 and 150 cases per 1,000 population.

p In the USSR, as in a number of other socialist countries, the problem of mental diseases is not so acute. Moreover, according to several studies conducted in recent years, the incidence of some mental disorders is tending to decrease.

p In the USSR the incidence of mental diseases among both urban and rural population is only one-third or even onequarter of that registered in several economically developed capitalist countries. This essential difference in mental health is hard to explain; it requires special studies. At any rate, it is clear that the explanation must be sought mainly in the fundamental differences in the social conditions and in the social policy pursued by the socialist state which is aimed at ensuring the well-being of the people and care of their health.

p This chapter is entitled the "Health Index”. For people familiar with medical statistics these words signify a definite index of the state of health, representing’ the percentage of people who never fell ill in the course of a year. Obviously, this coefficient is one of the most vivid indices of social health, although it has not as yet been widely used in scientific literature. In the Soviet Union this coefficient is used increasingly more often, particularly in characterising the state of health in children. According to a number of studies conducted in recent years, the "health index" is constantly rising. A special study carried out in Moscow in 1953 showed the "health index" of children in the first year of life to be about 14 per cent. Recent studies have yielded a much higher index. In one of these studies conducted in the city of Kaluga (1964-1966) the "health Index" was found to be 26.9 per cent, which means that in this city one-fourth of all the children under one year of age were never ill.

p The "health index" is also used increasingly more often to determine the state of health of adults. For example, a study of the health of the workers in a number of Moscow factories (1965 and 1966) revealed that in the course of a whole year, between 25 and 30 per cent or even more of the workers never called at medical institutions.

The "health index" is important not only as a precise statistical index, but also as a symbol of the magnificent improvements achieved in the state of Soviet public health.