The importance of Shigella boydii in shigellosis morbidity in the USSR

The etiological role of S. boydii in Shigella infections registered at different territories of the USSR in 1986-1987 was analyzed. As established by this analysis, S. boydii infection occurred mainly at the territories with unsatisfactory water supply of the population; from these territories the infection spread to ther territories of the USSR. The dominating serovars causing S. boydii dysentery, as well as Shigella infections, at different territories of the USSR was shown to be identical, which was indicative of the fact that the immunological factor had no influence on the etiological structure of Shigella infections, determined by the activity of the main routes of the transfer of infection. On the whole, S. boydii serovars 2, 4 and 1 were found to prevail in the USSR.     

Analysis of the trends in typhoid-paratyphoid morbidity in the USSR]

Mathematico-statistical analysis of typhoid-paratyphoid infection morbidity in the USSR during 1900--1940 revealed a regular many-year cyclic recurrence of the changes in the morbidity level. The intensity of the morbidity level reduction at the periods of decline--in 1900--1917, 1920--1928, and in 1932--1939--was similar. A successive reduction of morbidity of this group of infections, by 6.45% on the average, annually, occurred in 1930--1976. The character of reduction of typhoid-paratyphoid infections morbidity level in the USSR during that period is well described by the exponential function.     

The main characteristics of outbreaks of hospital infections in the USSR in 1986-1988

The analysis of 69 outbreaks of hospital infections in different regions of the USSR in 1986-1989 (the number of patients affected by these infections was 1,517) showed that most of these outbreaks (41) occurred at hospital wards for newborn infants. Acute enteric infections prevailed in the total structure of the outbreaks (73.7%). Purulent septic infections among newborns constituted a quarter of all outbreaks. Opportunistic microbes, and mainly Klebsiella, were the dominating element in the etiology of outbreaks in hospital wards for newborn infants. In pediatric wards in among adult hospital patients the etiology of outbreaks was completely, or almost completely, determined by pathogenic microorganisms, mainly salmonellae and shigellae. Outbreaks among hospital patients of three above-mentioned groups were characterized by differences in sources, routes and factors of the transmission of infection.     

Epidemiologic analysis morbidity with meningococcal infections in the USSR]

The authors present the analysis of the incidence of epidemic cerebrospinal meningitis in the USSR from 1937 to 1974, and of meningococcus infection from 1965 to 1974. A rise of the meningococcus infection incidence from 1969 to 1974 was recorded 28 years after the elevation of 1940-1942 and was 1.5 times below this latter rise. The rise in 1969-1974 was characterized by marked signs peculiar to the infection with the droplet transmission mechanism; among those who contracted the disease prevalence was seen among children aged under 14 years (63-72%). A marked affection of juveniles was noted. Three types of the dynamic of the meningococcus infection incidence in the republics located in different climatic-geographical zones of the USSR were noted: slow, gradual increase of the level, interrupted and explosive. Such character was determined in the dynamics of the seasonal elevations of morbidity. Antiepidemic measures including a complex of nonspecific measures could not be assessed as sufficiently effective. This finds reflection in the natural course of the epidemic process of the meningococcus infection which remains uncontrolled. From the patients with generalized form of the disease meningococci of group A were isolated in 80-100% of cases, from the number of those typed. The group-specific reference of the nasopharyngeal strains depended on the epidemic situation: strains of serological group A prevailed at the period of the morbidity elevation, and other serological groups (particularly of C and B) increased at its decline.     

The real place of infectious pathology in overall population morbidity

The statistical decrease of the proportion of infections in the structure of morbidity of the population reflects the existing classification of diseases when only acute diseases are classified with the group "infectious and parasitic diseases". The proportion of diseases caused by infective agents remains constantly high. According to WHO data, such diseases make up one-third of all diseases in the world. In Moscow the proportion of infectious diseases in all diseases registered among the inhabitants of this big city fluctuated within 36.1% and 49.7% during the period of 1926-1997.     

Means of optimizing the epidemiological surveillance of infectious diseases in the USSR

The present work shows the specific features of the epidemiological surveillance of infectious diseases, carried out by the All-Union Centers of the Central Research Institute of Epidemiology (sponsored by the Ministry of Health of the USSR) in different regions of the USSR with due consideration of the specific features of each disease.     

Analysis of the dynamics of typho-paratyphoid infection morbidity over the years in the USSR]

Statistical materials of recording the number of patients and of the typhoid-paratyphoid infections morbidity level in Russia and the USSR from 1891 to 1976 was studied. A stable tendency to reduction of this morbidity was noted. In analysing the empirical and flattened--by 3 and 5 points--curves of the number of patients and the morbidity level a regularity of declining morbidity rises was revealed. Elevation periodicity persisted, despite the reduction of morbidity level. The mean duration of the whole cycle constituted 12 years. The period of increasing morbidity from minimal to maximal in each cycle constituted 4 years, and of the declination period--8 years. Formalized empirical series of the number of patients and of the morbidity level deviated from 1908 to 1956 not more than by 1 year from the formalized basic curve. Cyclic changes of typhoid-paratyphoid infections morbidity should be taken into consideration in determining the efficacy of prophylatic measures, particularly of mass vaccination.