Nature of the epidemic process in Sonne and Flexner dysenteries and the causes of its induction

A comparative study of the epidemic process in Sh. sonnei and Sh. flexneri dysentery in different regions of the USSR revealed that the morbidity level of Sh. sonnei dysentery changed simultaneously in the regions under study at intervals of 2-3 years. Sh. flexneri dysentery showed morbidity rises occurring at intervals 6-8 years, and their occurrence did not coincide with the periods of elevated morbidity in Sh. sonnei dysentery. The data obtained in the cohort analysis and in the study of recurrent morbidity suggest that Sh. flexneri dysentery produces more pronounced postinfection immunity than Sh. sonnei dysentery, and the immunological factor probably affects the dynamics of the epidemic of these Shigella infections.     

Manifestations of the cyclic nature of the epidemic process in dysentery

Different forms of dysentery, especially those caused by Sh. sonnei and Sh. flexneri, have been found to differ considerably in their cyclic recurrence. The development cycles of the epidemic processes of dysentery have an objective character, occur in the presence of any tendencies in the morbidity rate, and depend on the natural factors. Thus, the cycles of increase and decrease in morbidity are 3, 6, 9, 12 years for dysentery caused by Sh. sonnei and 6, 7, 8 years for dysentery caused by Sh. flexneri.     

The structure of the population morbidity with specific intestinal infections in areas with different intensities in the development of the epidemic process and an evaluation of its manifestations]

The authors analyze the morbidity structure in five enteric infections (typhoid fever, dysentery caused by Shigella flexneri and Shigella sonnei, hepatitis A, and hepatitis E (non A, non B) with the fecal/oral mechanism of the agent transmission) in three towns of Turkmenia and in the town of Novomoskovsk, Tula Province. The incidence of S. sonnei dysentery was found higher in Novomoskovsk and that of the rest enteric infections under study in Turkmenia. The incidence of typhoid fever and hepatitis E was the highest among schoolchildren and adults, whereas preschool children suffered mostly from hepatitis A and S. sonnei dysentery. The authors discuss the specific features of the epidemic process manifestation in enteric infections.     

Recurrent Sonne dysentery morbidity caused by Shigella of varying enzymatic types]

The proportion of repeated cases of dysentery caused by Sh. sonnei does not exceed 3.59% of the total number of bacteriologically confirmed cases of this infection. The frequency of reinfection depended on the enzymatic type of the causative agent. The rarest cases of reinfection were those occurring after the primary infection with Sh. sonnei, biochemical type 2, whereas the most frequent after the primary infection with Sh. sonnei, type 3. Reinfection with heterologous Sh. sonnei was registered mostly 6-12 months after the primary infection, and with homologous Sh. sonnei after a 1 year and later.     

Tendencies in the epidemic process of dysentery in Ryazan

In shigellosis caused by Sh. sonnei and Sh. flexneri the epidemic process was found to have considerable difference in the tendencies and pace of its development. Shigellosis which dominated in the etiological structure at the period following 1966 was dysentery caused by Sh. sonnei; it showed the tendency towards a decrease in morbidity rate. Dysentery caused by Sh. flexneri was second in respect to the frequency of its occurrence after 1966 and showed the tendency towards increase. The simultaneous circulation of Sh. sonnei and Sh. flexneri, the differences in the epidemiology of these types of shigellosis make it imperative that they be studied separately, taking into ccount their etiological selectivity to the main routes of transmitting the infection.     

Use of data on Shigella contamination and immunity indices for studying the activity of the epidemic process in dysentery

The comparative study of the monthly distribution of characteristics indicating the levels of contamination with Sh. sonnei and Sh. flexneri separately, as well as the seasonal dynamics of the corresponding antibodies, in the years with high and low morbidity levels has been made with the use the indirect hemagglutination test. The possibility of using these characteristics for the evaluation of the activity of the epidemic process in dysentery caused by Sh. sonnei is shown.     

Effectiveness of social hygiene and organized preventive measures in dysentery in preschool institutions]

The work presents the data on the development and realization of the complex of social and hygienic, as well as organizational and preventive measures for dysentery control at institutions for children of preschool age in one of the regions of our country. This complex comprises the improvement of "epidemiological" knowledge of the staff, preventive orientation in the work of the epidemiological section of the local Sanitary Epidemiological Station, the spread of sanitary and hygienic knowledge children and in their families, the improvement of material and technical equipment of children's institutions. The complex proved to be highly effective: at institutions for children of preschool age morbidity -ate in dysentery decrease 4--5 times, and its specific falue dropped from 40% to 5.4%, the frequency of positive results given by tests for the presence of intestinal microflora in washings from various objects decreased more than 25 times. Morbidity rate at institutions for children of preschool age decreased 4--5 times as compared with that among children not attending such institutions. The above data suggest the necessity of introducing this experience in other regions of our country.     

Patterns determining the dynamics of the epidemic process in Sonne dysentery and its relation to the type of causative agent]

The results of studying the dynamics of the epidemic process of dysentery, based on the data from 3 districts of Moscow, are presented. The study revealed the periodicity of 3 years in the course of the epidemic process of dysentery, occurring against the background of a considerable predominance of Sh. sonnei, biochemical type 2. The use of the cohort method for analyzing the age structure of dysentery cases showed the possibility of using this method to find out to what extent the epidemic process repeatedly affected the same groups of population.     

Serological method of detecting the antigens of the causative agent of Sonne dysentery in lysates of the fecal inoculates from patients]

Serological method of detection of Sh. sonnei antigens in the lysates of the patients, fecal cultures is suggested and approved. In the majority of cases of the results of bacteriological and serological methods of study of the feces coincided. Data confirming the specificity of the antibody neutralization test (ANT) in Sonne dysentery are presented. In connection with detection of the screening action of the Vi-antigen of typhoid bacilli there were elaborated additional methods for verifying the specificity of the ANT results. It is recommended to keep agar plates after selection of suspicious colonies during the bacteriological test; the lysate of the microbial crop should be additionally subjected to the ANT, this considerably increasing the percentage of laboratory confirmations of dysentery caused by Sh. sonnei.     

Epidemiological pattern of scarlet fever in recent years

During the period of 1953-2001 scarlet fever morbidity level fluctuated from 670.3 to 65.9 per 100,000 of the population in Moscow and from 531.9 to 35.0 per 100,000 of the population of the Russian Federation. In recent years an increased morbidity was more pronounced in Moscow than in the Russian Federation as a whole. Children formed the greater part of scarlet fever patients, the cases of scarlet fever among children in Moscow occurring more often than, on the average, in Russia. As before, annual morbidity among children attending children's institutions was higher 3- to 4-fold than among children brought up at home. This difference was most sharply pronounced among young children during the first two years of their life. In contrast to morbidity observed during previous 20-30 years, a drop in morbidity among children during the first two years of their life was registered, while morbidity level among children aged 3-6 years and 7-14 years increased. Scarlet fever morbidity had a pronounced seasonal (autumn-winter) pattern. In a group of children aged 3-5 years who attended organized groups, on the average, 78.6% of scarlet fever cases fell on seasonal morbidity, the most prolonged one.     

Use of intraspecific differentiation of Sh. sonnei for the purpose of studying patterns in the epidemic process of dysentery]

The use of complex typing of Sh. sonnei by the colicinogenic and enzymatic properties in epidemiological analysis of dysentery caused by Sh. sonnei, apart from establishment of epidemiological connections in the foci, offered a possibility of introducing significant corrections in the determination of the sizes and duration of existence of the epidemic foci, as well as in detection of the sources and factors of transmission of the infection established in epidemiological examination. Typing of Sh. sonnei also aided in ascertaining that, apart from general regularities in the individual territories, the epidemic process in individual groups of the population and in different seasons of the year could also course autonomously.     

痢疾杆菌不同群、型间交叉保护性试验研究

本文对痢疾杆菌不同群、型间的交叉保护作用进行了观察。试验模型为恒河猴,将其分为４组,第一、三组分别为感染过福氏１ａ和宋内菌并已康复的猴;第四组为用双价菌苗株ＦＳ（福氏２ａ和宋内）免疫的猴体,剂量依次为４×１０１０、６．５×１０１０、６×１０１０,共１６．５×１０１０活菌,第二组为空白对照。所有４组皆用福氏２ａ２５８００×１０８活菌攻击。从发病率来看,不同菌群与菌型间没有明显的交叉保护作用;从发病程度看则一组显著低于对照组,三组与对照组无显著差异,此结果表明痢疾杆菌Ｂ群内存在交叉保护作用,但较同型保护作用弱。     

Patterns in the spread and serovirological diagnosis of serous meningitis

The epidemiological and clinico-etiological study of cases of acute serous meningitis with unknown etiology in children was carried out in a large industrial city at the period of a considerable morbidity rise caused by this infection. The maximum morbidity was registered among younger children under school age attending children's institutions. In 26 closed groups of children group morbidity was revealed (4 cases and more), in 5 such groups small local outbreaks were registered. The clinico-instrumental methods of study permitted one to differentiate the groups of children having serous meningitis of supposedly enteroviral etiology, and sero virological studies carried out with the use of a wide range of diagnostic reagents revealed the etiological role of group B Coxsackie virus, mainly type 4, in 20.6% of cases, ECHO virus, serotypes 3 and 11, in 20.7% of cases, and parotitis virus in 5.3% of cases.     

Modern methods of intraspecies typing of Sonne shigellae. II. Spread of Sonne shigellae of different biochemical types]

The paper presents the results of studying peculiarities of the Sh. sonnei of different biochemical types spread established by their typing scheme suggested by the authors earlier according to rhamnose, xylose and maltose. The epidemic process in dysentery both during the years of the rise and of the decline of its incidence at various territories of the countries proved to be maintained on account of circulation of Sh. sonnei of various biochemical types. The results of studying their dissociative and virulent properties confirmed the biological separation of individual biochemical types. An interrelationship between the character of the biochemical pattern of Shigellae sonnei at the individual territories and the persisting activity of different ways of dysentery transmission was determined. The results of studying the biochemical pattern could be used as an indicator of the degree of activity of individual ways of dysentery spread at various territories.     

Immunoelectrophoretic analysis of the antigenic structure of Sh. sonnei]

The authors studied the antigenic composition of 105 Sh. sonnei strains freshly isolated from patients suffering from acute dysentery and carriers. Immunophoregrams of pure S-and R-forms species were obtained. Up to 13 antigens differing by electrophoretic and diffusion mobility and immunological specificity were revealed among soluble Sh. sonnei antigens The position of common and specific antigens was determined on the immunophoregram. Along with the thermostable somatic O-antigen detected at the I phase of the S-forms, and two thermolabile O-antigen components at the II phase, and the R-forms, there was revealed a surface, relatively thermolabile, K-antigen of A-type capable of agglutinating live bacteria in the O-antiserum; position of the latter on the immunophoregram was also determined.     

Current methods of intraspecies typing of Shigella sonnei. 3. Bacteriophage typing]

Data are presented concerning the study of the phage type of Sh. sonnei isolated in various regions of the USSR. The strains isolated belonged to 64 phage types corresponding to the Hammarstr?m's scheme. A variety of Shigella sonnei phage types both in one and in different territories of the country provided future prospects for successful use of phage typing for the purpose of epidemiological supervision and analysis of dysentery morbidity.     

Relation of the epidemiological characteristics of dysentery to the biological properties of the causative agents

The main forms of the epidemic manifestation of dysentery induced by different causative agents in 1975-1980 were revealed. During these years the cases of dysentery induced by Shigella sonnei, biovar II, were found to prevail (82.0-90.1%) both at the periods between epidemics and at the periods of the seasonal rise of morbidity. The experimental infection of white mice by intraperitoneal inoculation revealed no relationship between the seasonal rise of morbidity in dysentery and the virulence of its causative agents.     

Determination of the O antigen of Shigella sonnei by a competitive immunoenzyme method

A technique for immunoenzymatic diagnosis of dysentery by Shigella sonnei O-antigen was developed. For induction of antibodies to O-antigen rabbits were immunized by intravenous administration of a commercial antidysentery vaccine. Specific antibodies to O-antigen belonging to class G immunoglobulins and not binding to O-antigens of Sh. flexneri and Salmonella typhimurium were obtained. beta-Lactamase of Bacillus licheniformis 749/c was used as a marker enzyme in the immunoenzymatic assay. To increase the sensitivity, beta-lactamase molecules were preliminarily linked with glutaric aldehyde into oligomers. Conjugates of Sh. sonnei O-antigen with the oligomers of B. licheniformis 749/c beta-lactamase were prepared with the periodate method by oxidizing O-antigen. The conjugate was used in competing solid phase immunoenzymatic assay for determination of Sh. sonnei O-antigen in blood serum of patients with dysentery. The sensitivity of the assay is 0.5-1 ng per 1 ml of O-antigen.     

To shigellosis epidemicity in East-Slovakian region

A set of 2227 strains of Shigella sonnei isolated from dysentery patients in East-Slovakian region from 1975 through 1977 was analyzed by age and sex of patients, place and time of isolation, and by phage type, colicin type and antibiogram patterns of strains. The study showed that some phage types tended to occur in association with certain colicin types, the most common combination being that of phage type 75 and col factór Ei (86% of strains). In 1976 and 1977 this phage type gradually replaced col factor Ia that in 1975 was predominant. The rise in the incidence of these strains was striking and pointed to their intensive circulation among the population of East-Slovakian districts, particularly among children of preschool age. A hypothetic assumption is that such changes in the phage type and colicin type patterns might precede the new epidemic wave of dysentery outbreaks in the population. That would also explain e.g. the irregularity of dysentery epidemic cycles encountered in Czechoslovakia during the decade from 1972 through 1982. The analysis of strains by pattern of antibiogram showed that the percentage of strains resistant to all antimicrobials and sulphonamides tested remained virtually constant over the three years under study and did not exceed 6% of strains. Only the strains monoresistant to tetracycline were found to show a striking rise in their incidence from 5% in 1975 to 23% in 1977. In the majority of cases they were S. sonnei strains with col factor Ei.     

Course of dysentery and the specific alteration of the neutrophils in children in the use of monomycin and a diet with an increased protein content]

Acute dysentery mainly due to Shigella sonnei and dynamics of the neutrophil damage index (NDI) of the blood were studied in 80 children at the age of 1 to 14. 20 children (group 1) were treated with monomycin under conditions of a diet with an excessive content of protein (by 25% higher than the physiological norm). 60 children or 3 groups of 20 children each were not subject to such conditions and were considered as control groups. Reduction in the time of recovery (by 4 days) and bacteriological sanation (by 6 days) of the convalescents in the 1st group decreased as compared to that in the control groups. The test for the NDI of the blood was close in all the groups. It was concluded that an excessive protein content in the diet increased the efficacy of monomycin therapy in dysentery children. It is recommended that the diet with an excessive protein content be used in monomycin treatment of dysentery children.