The system of epidemiological surveillance as a reflection of the structure of the epidemic process

The socio-ecological concept in epidemiology, formulated by the author in his earlier works and regarding the epidemic process as a biosocial hierarchical, integral system, can serve as a theoretical basis for the epidemiological surveillance of infectious and parasitic diseases. In accordance with the structure of the epidemic process, the system of epidemiological surveillance is subdivided into the following monitoring levels: molecular, microbiological, clinical, biocenological, statistical and sociological. The functions of epidemiological surveillance should be performed by the existing and newly organized All-Union Centers for the corresponding nosological forms.     

The epidemic process of diphtheria infection in the RSFSR during the introduction of epidemiological surveillance

In this work the characterization of the epidemic process of diphtheria infection on the territory of the RSFSR under the conditions of epidemiological surveillance (1983-1986) is presented. In comparison with the period of 1979-1982, an increase in morbidity rate occurred, which accounts for more complete detection of patients with mild forms of diphtheria, including persons found to be carriers of toxigenic Corynebacterium diphtheriae. Beginning from 1983, the leveling out of seasonal morbidity rises is observed. In the total number of persons affected by this infection the prevalence of adults is noted. Among them, a decrease in the morbidity rate was registered in 1986 (the maximum decrease was observed in age and professional groups of risk), which confirms the effectiveness of measures carried out for the protection of the adult population from diphtheria. Among children, a tendency towards a decrease in morbidity rate was noted in all age groups. The existing system of epidemiological surveillance on the territory of the RSFSR is capable of stabilizing diphtheria morbidity on a sporadic level and minimizing the number of fatal outcomes. The intensification of the epidemic process in some areas of the RSFSR is due to shortcomings in the realization of different measures of epidemiological surveillance.     

Serological surveillance of diphtheria

The serological method (indirect hemagglutination test) has been used in the surveillance of diphtheria infection. The structure of immunity to diphtheria in the population of the region has been studied. The possibility of increasing intervals between booster immunizations has been confirmed. The introduction of planned booster immunizations of the adult population with diphtheria toxoid is proposed.     

Prevention of acute intestinal infections based on the epidemiological surveillance system

The development of the system of epidemiological surveillance and its introduction into the practical work of the district sanitary and epidemiological station made it possible to decrease morbidity in acute intestinal infections 2.4 times in comparison with preceding years, as well as to put an end to the outbreaks of these infections. The work proved the advantage of epidemiological diagnosis permitting the introduction of measures which prevent the formation of the epidemic strain of the infective agent and thus affect the seasonal rise of morbidity.     

Immunological structure of the population vis-à-vis the meningococcus]

The immunological and epidemiological study of 3362 serum samples selectively taken from healthy persons in Yaroslavl showed the presence of highly pronounced inverse correlation between morbidity rate indices and level of antibodies, as well as direct correlation between the level of carriership and the level of antibodies, which indicated the specific character of this process. The analysis of serological data showed that all meningococcal antigenic fractions took part in the formation of the immunological structure of the population, but lipopolysaccharides and polysaccharides played the most active role in this process. The level of all immunoglobulin classes (especially IgA) in the sera of the persons selected for this study was also shown to depend on their age.     

The principles of pre-epidemic diagnosis in the epidemiological surveillance system for HIV infection

The problem of the general introduction of the principles of the pre-epidemic diagnostics of HIV infection was discussed. These principles should be based on the observation of "model" infections (viral hepatitides B, C, D), multipurpose serological monitoring and sociological methods aimed at obtaining the necessary information. The suggestion that the age and sexual structure of HIV-infected patients would be determined by the route of HIV transmission, prevailing on a given territory, including into infection process adolescents and young women and men was made.     

Current epidemiological surveillance of tuberculosis

Some present-day specific epidemiological, microbiological and clinical features of tuberculosis are presented. A variant of the epidemiological surveillance morbidity scheme, comprising 3 blocks, viz. information, analysis and management, is proposed. In the information block the basic data necessary for epidemic analysis is listed, while the diagnostic block contains the stage-by-stage analysis of the information block data. In the block of management decisions the main directions of the tuberculosis prophylaxis interventions are listed.     

Epidemiological surveillance of diphtheria infection in the territory of the Azerbaijan SSR

A complex of measures carried out with a view of effecting the epidemiological surveillance of diphtheria infection has made it possible to study the level and intensity of immunity to diphtheria and tetanus, determined in the passive hemagglutination test, in the child and adult population and to reveal groups, least protected against diphtheria infection. Bacteriological studies on the biological properties of Corynebacterium diphtheriae have revealed the contamination of various groups of children with this infective agents and permitted its complete characterization with the determination of its sero-, phago- and corycinovariants.     

Immunological characterization of diphtheria toxin recovered from Corynebacterium pseudotuberculosis

Diphtheria toxin (DT) is a potent toxin produced by the so-called diphtheria group which includes Corynebacterium diphtheriae (C. diphtheriae), Corynebacterium ulcerans (C. ulcerans), and Corynebacterium pseudotuberculosis (C. pseudotuberculosis). The present investigation is aimed to study in detail the production of DT by C. pseudotuberculosis. Twenty isolates were obtained from sheep diseased with caseous lymphadenitis (CLA) and twenty-six isolates were obtained from 26 buffaloes diseased with oedematous skin disease (OSD). All isolates were identified by standard microbiological and DT production was assayed serologically by modified Elek test and immunoblotting. All sheep isolates were nitrate negative, failed to hydrolyze starch and could not produce DT, while all buffalo isolates (biotype II) revealed positive results and a specific band of 62 kDa, specific to DT, was resulted in all concentrated cell fractions (CF), but was absent from non-toxigenic biotype I isolates. At the same time, another band of 31 kDa specific to the PLD gene was obtained with all isolates of biotype I and II. Moreover, all isolates showed positive synergistic hemolytic activity and antagonistic hemolysis with β-hemolytic Staphylococci. The obtained results also indicated that C. pseudotuberculosis could be classified into two strains; non-toxigenic biotype I strain, which failed to produce DT as well as being negative to nitrate and starch hydrolysis, and toxigenic biotype II strain, which can reduce nitrate, hydrolyze starch as well as produce DT.     

Erroneous information in the epidemiological surveillance of hepatitis B

False positive results obtained in the determination of the immune markers of hepatitis A by the methods of the passive reverse hemagglutination test and the enzyme immunoassay distort the course of the registration of the epidemic process and deteriorate the quality of the antiepidemic measures ensured to the population. The necessity of the standardization of available test systems is postulated.     

The epidemiological surveillance of poliomyelitis in the Ukraine]

Correlation has been revealed between the circulation of polioviruses among the population and environmental objects. A rise in the circulation of polioviruses, type I, was caused by a decrease in collective immunity to this virus type. Water supply and sewage system purification was found ineffective with respect to enteroviral contamination. Vaccinal prophylaxis, carried out for many years, did not lead to the elimination of poliovirus strains, genetically different from vaccine ones.     

Current problems of the epidemiological surveillance of poliomyelitis

A uniform program of the epidemiological supervision of poliomyelitis must be worked out for every administrative territorial unit. This program should include the early and complete detection of all cases of this infection, irrespective of their severity; the analysis of the quality of vaccination; the determination of the immune status of the child population; the characteristic of the poliovirus circulation.     

Criteria of the epidemiological surveillance of meningococcal infection

The results of studies carried out with the use of the unified, specially developed methods in eight regions of the USSR are generalized. Basing on the analysis of the results, the leading role of serogroup A meningococci in the rise of morbidity is emphasized, the relation of the morbidity level to the serogroup composition of meningococci circulating among healthy population is revealed, the necessity of carrying out selective bacteriological surveys with a view to establish the serogroups of meningococci circulating among the population is shown. The expedient criteria to be used in the system of epidemiological surveillance of meningococcal infection are presented.     

Electron microscopy as a diagnostic method in the epidemiological surveillance of poxvirus infections

The materials of work lasting for 11 years and including the study of 3,425 samples collected at different periods after the eradication of smallpox from patients suspected for orthopoxvirus infection indicate high effectiveness of electron microscopy and especially immune electron microscopy as an integral part of diagnostic examination.