Search

Periodization of the evolution of epidemic process of hepatitis C is given based on the results of phylodynamic, phylogeographic, historic and demographic studies: invasion of the virus into European and North-American population in 1700-1850; primary activation of the epidemic process in the years of the World War 1; expansive giowth of prevalence in 40--60s of the 20th century due to mass parenteral interventions; new rise due to heroine drug abuse in 60--80s of the 20th century; manifold reduction of incidence of acute hepatitis C in industrial countries for the last 10-15 years as a result of general medical measures of prevention of hemocontact infec-tions. A problem of possibility of hepatitis C management and necessity of evaluation of effectiveness of existing prophylaxis measures involving quantitative analytical methods of epidemiology is discussed. Data from phylogenetic studies on stages of hepatitis C virus evolution (HCV) are provided: division of its root genetic lineage with homologous hepaciviruses of animals 985--2013 years ago; division of HCV into genotypes 500--2000 years ago; division of genotypes into subtypes 70--300 years ago. Contribution of mutations and genetic recombinations into HCV evolution is discussed. Genotyping is stated as an inefficient approach for determination of pathogenicity determinants, immune evasion, non-responsiveness to therapy, as well as search for predictors of infection outcome. A necessity of genomic approach for these aims is justified, as well as for risk monitoring, ensuing from continuing evolution and biodiversity of HCV and other hepaciviruses.

High disease burden of chronic virus hepatitis B and C of population in the Republic Sakha (Yakutia) is subject to referring it to endemic territories due to these infections. For a 15-year-old period the disease has been registered at higher rates in the Russian Federation.

Hepatitis C virus is an actual public health problem worldwide since its discovering in 1989. It is explained not only by the wide spreading and frequent adverse outcomes of disease, the lack of effective preventive vaccine, but also by the high genetic variability of the virus. The current review summarizes the results of phylodynamic and phylogeographic studies of different HCV populations that allowed to characterize epidemic processes, to analyze the divergence of HCV into genotypes and subtypes, and to determine the geographic origin of the current HCV epidemic variants.

The notion "molecular epidemiology" was introduced into scientific literature by Kilburn E. et al. in 1973. The first period of development of infectious diseases molecular epidemiology may be called "genotypic" (1980-1990s). During this period methodology of molecular marking of pathogens for purposes of monitoring of their spread and outbreak detection (novel nomenclature of diphtheria corynebacteria based on ribotyping; international network PulseNet for monitoring food source infections; international database of tuberculosis mycobacteria spoligotypes) was created. The second--"genomic" period started in the 2000s. Molecular epidemiology rapidly went through single markers (genotypes or single genes) to deciphering the whole genome of pathoge "mobileome", "resistome", "virulome" etc. took an important place in the studies of emerging and pandemic infections. Knowledge on genetic mechanisms leading to emergence and global dissemination of novel pathogens give molecular epidemiology its own scientific content and transforms it from a methodical approach to an independent field of epidemiology. The third--"metagenomic" period starts nowadays based on meta-genomic approach that allows to determine the whole set ofgenomes in the studied sample without the cultivation procedure. In the short-term this would lead to a change of a century-long paradigm of diagnostics and control of infections: instead of search of separate (key) pathogens--characteristics of the full specter of microorganisms in the material from patients and environmental samples with its identification up to any taxonomic depth. In the systems of regional and global epidemiologic control a universal monitoring of all known and re-emerging pathogens with construction and maintenance of metagenomic passports of human habitats will be realized.

Aim: Evaluate the state of immunity against pertussis in children living in St. Petersburg and regional centers of Northwestern Federal District (NFD)., Materials and Methods: The level of anti-pertussis antibodies by EIA and agglutinin reaction (AR) was studied in 419 children living in St. Petersburg and by AR in 239 children living in regional centers of NFD. Blood sera in AR were studied by using liquid pertussis diagnosticum (Biomed, Russia)., Results: In St. Petersburg the frequency of detection of high level of antibodies was the highest in the 15 - 17 age group that indicates a high level of latent morbidity in grownups. The frequency of detection of high level of antibodies in the 3 - 4 and 9 - 10 age groups in regional centers was significantly lower, and the fraction of sera with undetected level of antibodies--significantly higher compared with St. Petersburg, that gives evidence on low circulation of causative agent, lack of "epidemizing" of children in small cities., Conclusion: The question of introduction of second revaccination against pertussis in children at the age of 6 is actual, because one vaccination is not enough for prolonged sustaining of population immunity intensity.

Aim: Study H. pylori strains circulating in St. Petersburg among patients with various gastrointestinal tract pathology as well as study of frequency of infection by H. pylori based on serological markers data among this group of patients., Materials and Methods: By using serological method 162 individuals with various chronic diseases of stomach and duodenum were examined. The presence in blood serum of IgG against H. pylori bacterial antigen and IgG against its toxin--CagA was studied. 129 patients were examined bacteriologically, biopsy samples of stomach mucous membrane were studied. PCR in real time format was used for study of H. pylori strains (49) and biopsy samples (36) of stomach mucous membrane., Results: The analysis performed showed that on the territory of St. Petersburg H. pylori strains containing cagA gene predominate (81.63% of the isolated strains). Genotyping of strains by vacA showed that s1m1 genotype was more frequent (in 57.14% of cases). The fraction of CagA positive strains in patients in St. Petersburg is maximum for stomach cancer (90.8%), whereas for peptic ulcer disease and gastritis it is 64.7% and 72.2%, respectively. In patients with stomach and duodenum pathology the parameters of seropositivity for H. pylori were significantly higher than in individuals without clinical manifestations of H. pylori infection (86.72% against 65.09%; p < 0.05)., Conclusion: The data obtained on increase of fraction of CagA positive strains among H. pylori circulating in St. Petersburg determine the importance of conducting eradication H. pylori.

Aim: Study of prevalence of Helicobacter pylori infection in one organized children community of St. Petersburg in the current period., Materials and Methods: 390 children and adolescents of one of the general education schools of St. Petersburg were examined. Presence in blood sera of IgG to bacterial antigen of H. pylori and IgG to its CagA toxin by ELISA method was studied. In 222 children feces samples were studied. Determination of presence of H. pylori antigen in the feces was carried out by using Helicobacter pylori antigen ELISA Kit, Immundiagnostik test system., Results: Comparison of H. pylori infection prevalence in children of various age revealed that infection is minimal in children aged 7 - 8 years (36.84%) and reaches maximum levels in students aged 14 years (66.67%). Screening result shows that there are 2 waves of H. pylori infection (the first peak was detected in 11 years, the second - in 14 years). Excess weight in H. pylori positive students is present less frequently (19.89% versus 30.13%). The difference is more notable in boys (20.25% and 38.75% respectively)., Conclusion: A sufficiently high level of infectivity by H. pylori in the students of this school was detected. It was established, that seropositivity increases with student age and reaches maximum levels in upperclassmen. 2 waves of H. pylori infection curve are noticed. It was detected that excess weight occurs more frequently in children not infected by helicobater (p<0.05). Combination of various diagnostic methods gives more precise information on the presence of H. pylori infection.

Aim: Determination of genetic and molecular features of pathogens circulating in Russia, in the northwest of the country and in St. Petersburg to resolve the problems of spread of diseases caused by these pathogens., Materials and Methods: Complete and limited gene sequencing, DNA restriction fragment length polymorphism analysis, spoligotyping, VNTR-typing, resistotyping and other methods were used., Results: Data on population structure and dominant genotypes of tuberculosis mycobacteria, corynebacteria, helicobacteria, hepatitis A, B, C, human papilloma viruses circulating in Russia, in the northwest of the country and in St. Petersburg were obtained. Genetic divergence of rubella virus and poliovirus vaccine strains under mass vaccination conditions was detected. Evidence of higher effectiveness of pathogen genotyping methods in epidemiologic diagnostics compared with traditional epidemiological investigation was obtained., Conclusion: Microorganism genotyping methods were helpful in resolving strategic problems of contemporary epidemiology. Perspectives of further development of these methods are related to obtaining data on circulating genotypes in all regions of the world, establishment of complete databases on circulating genotypes and integration of this methodology into daily diagnostics and epidemiological surveillance.

Aim: Studies of Helicobater pylori infection rate among population of North-western federal district including St. Petersburg in 2007 - 2009., Materials and Methods: 1021 individuals with various digestive tract pathologies as well as healthy individuals and blood donors were examined. 378 children and adolescents up to 19 years of age, and 643 adults 20 - 80 years of age were among the examined individuals. IgG to H. pylori complex antigen and IgG to its CagA toxin were determined in blood sera., Results: Infection rate among children and adolescents was 40.48%, CagA positive strain infection rate--34.92%. Among adults these parameters were 63.61% and 49.61%, respectively. During the 3 year study a tendency of CagA positive strain rate increase was noted among children and adolescents. Prevalence of H. pylori infection in subjectively healthy individuals, intestine oncology disease and gastric cancer patients was 55.1%, 67.16% and 83.33%, respectively., Conclusion: High rate of infection and CagA positive strain prevalence among children and adolescents can be considered as a possible factor of gastritis and ulcer rate increase in these age groups.

Aim: Development of test system for the evaluation of sensitivity of Trichomonas vaginalis to preparations of the 5-nitroimidazole and 5-nitrofuran groups., Materials and Methods: Determination of minimal cidic concentration (MCC) of antiprotozoal preparations was carried out by cultivating laboratory T. vaginalis strains in wells of plates with nutrient medium containing varying concentrations of these preparations. Evaluation of vitality of the agent was determined by using trypan blue vital stain and bysubsequent growth ability in nutrient medium without antiprotozoal preparations. Construction of the test system was carried out by selecting conditions for the fixation of preparations in the plate wells and control of activity retention after the fixation. 109 isolates from patients with confirmed trichomoniasis diagnosis were used for the approbation of the test system., Results: Cultivation of 10 strains showed that MCC of investigated preparations had the following values: metronidazole 5, tinidazole 1.25; secnidazole 2.5; nimorazole 1.25; ornidazole 2.5; clotrimazole 15; nifuratel 1.25 microg/ml. Studies of clinical material revealed single-type sensitivity of strains isolated during acute trichomoniasis, and varying--during chronic, while one strain had multidrug resistance., Conclusion: A simple test system available for routine laboratory work for the evaluation of sensitivity of T. vaginalis to preparations of the 5-nitroimidazole and 5-nitrofuran groups was developed. The efficacy of the test ensures high sensitivity, reproducibility and shorter procedure time as compared with classical method, thus allowing the selection of preparation for therapy with the highest probability.

Aim: To assess influence of vaccination against rubella on the genetic diversity of rubella virus., Materials and Methods: Vaccine strains of rubella virus Wistar 27/3 and Orlov-B as well as sera from patients with rubella obtained in Perm region during 1999 - 2005 period and standard serologic, molecular, epidemiologic and statistical methods were used. The study was performed according to the WHO recommendations on the genotyping of wild rubellavirus strains., Results: Strains of rubella virus isolated in Perm region, vaccine strain Orlov-B (Saint Petersburg), and 4 Russian strains isolated in 1967-1997 before vaccine introduction belong to the same genetic group with high degree of homology - genetic divergence do not exceed 0 - 1%. This group was identified as genotype 2c which, according to WHO's data, circulates only in Russia. Periods of epidemic peaks of rubella incidence and its falls as well as selective immunization of girls and women of childbearing age did not influence on the genetic stability of the virus (divergence did not exceed 0.6 - 2.0%). On the contrary, mass immunization of children aged 1 - 2 years during 4 years resulted in statistically significant changes of rubella virus subtype inside the genotype 2c., Conclusion: Ten-year experience of rubella vaccination in Perm region demonstrates necessity of inclusion of monitoring for rubella virus variability in the system of epidemiological surveillance and control for rubella infection during period of its prevention by vaccine.

The results of the study of 33 patients having gastroduodenal peptic ulcer, with 9 of them subjected to surgical treatment, are presented. The diagnostics of Helicobacter infection was made with the use of bacteriological and biochemical assays. The study revealed that in the overwhelming majority of cases peptic ulcer was associated with the presence of H.pylori, and the most informative method for the diagnostics of H.pylori infection was the bacteriological study of biopsies from the pyloric antrum characterized by the highest degree of massive contamination. The determination of ammonia concentration by biochemical assay with the use of Aerotest was most suitable for the diagnostics of H.pylori infection in patients with a short history of peptic ulcer.

The use of a recombinant poxvirus (RPV) strain, expressing HBsAg in the process of reproduction in different bioreactor systems under stationary and bioreactor conditions of cultivation, made it possible to obtain highly purified HBsAg. The identity and purity of HBsAg was confirmed by the analysis of its amino acid composition, SDS electrophoresis in polyacrylamide gel, electron microscopy and high-performance liquid chromatography. Good prospects of the use of RPV-expressed gene engineering HBsAg as the basis vaccines against hepatitis B was demonstrated in 10 experimental batches of vaccine. All batches of the preparation had pronounced immunogenicity and were safe and nontoxic in animal experiments. The ID50 of experimental batches did not exceed 211 ng/ml, which, according to the data of comparative experiments, was lower than, or equal to, corresponding values of analogous foreign commercial preparations, based on plasma or yeast HBsAg.

Regularities in the formation of autoantibodies to human IgA, IgM, IgG and their fragments, such as F(ab')2, Fab, Fc, in donors immunized with influenza vaccine (44 subjects) and staphylococcal toxoid (15 subjects) were studied with regard to the dynamics of specific immune response. After immunization with staphylococcal toxoid autoimmune reactions were registered only in the precipitation tests during 3-5 weeks of observation. In donors immunized with influenza vaccine the induction of isotypically heterogeneous autoimmune reactions was established. These reactions were represented mainly by IgA and IgG autoantibodies to immunoglobulins of different classes and their fragments. The duration of autoimmune reactions registered in this group of donors was specially noteworthy. The levels of autoantibodies to most of the antigens under study remained significantly elevated for 6 months. After immunization with influenza vaccine the presence of direct correlation between the level of specific immune response and the level of autoantibody formation was established.

The side-effect of nonvirion admixtures in inactivated influenza vaccines has been experimentally studied. The minimal sensitizing dose of allantoic admixtures other than ovalbumin has been experimentally determined in vivo. This dose has proved to be 4 times higher than the sensitizing dose of ovalbumin. The presence of sharply defined correlations between the concentration of the admixtures contained in inactivated influenza vaccines, the titers of antibodies to these admixtures and the severity of anaphylactic reactions has been established in guinea pigs after their multiple immunization.

Admixtures of free antigens have been shown to play the main role in the anaphylactogenic danger of vaccines. The immunogenic and anaphylactogenic action of such antigenic admixtures in corpuscular influenza vaccine can be observed after the immunization of animals in 2 or 3 injections. Host antigens incorporated into viral particles induce no anaphylactic reaction in guinea pigs after their immunization in 3 injections.

Rooster monospecific sera to influenza virus hemagglutinin free from antibodies to the host (chick embryo) admixture components were prepared and satisfactorily used in radial immunodiffusion test for control of the levels of hemagglutinin in influenza vaccines. The indirect hemagglutination test with erythrocytic antibody diagnosticum has been proposed for the detection of low ovalbumin concentrations. The sensitivity of this method is less than 0.003 micrograms/ml ovalbumin which significantly surpasses other currently accepted methods for control of this component in inactivated influenza vaccines. Immunochemical methods established the presence in influenza vaccines of other "nonovalbumin" multicomponent admixtures. Their sensitizing activity was characterized and found to be 4-5 times weaker than that of ovalbumin.

Corpuscular influenza vaccines have been found to contain chick embryo antigens differing from ovalbumin in their antigenic, immunogenic, and allergenic properties. The study has revealed that host antigens are present in vaccines in the form of free contaminants and as substances incorporated into viruses. The vaccine prepared by the method of sorption-elution on red blood cells with subsequent gel chromatography is characterized by the highest antigenic purity.

Two immunoaffinity chromatographic methods for the purification of corpuscular influenza vaccine from the admixture of chick embryo components have been examined. The isolation of the virus on immobilized antiviral antibodies has proved to be unsuitable for preparative purposes. The method for the purification of the vaccine from ovalbumin with the use of immobilized anti-ovalbumin antibodies has proved to be highly effective. When introduced into guinea pigs in 3 injections, the vaccine purified by immunosorption has been found to produce no anaphylactic reactions.

An attempt to obtain the preparations of peroxidase-labeled staphylococcal protein A, intended for use in the enzyme immunoassay, by the glutaraldehyde method has failed. The modified periodate method permitting the preparation of active conjugates of staphylococcal protein A with peroxidase has been developed.