The coronavirus disease pandemic (COVID-19) was announced by WHO in February 2020. In Moscow, the first case of the disease was detected on March 2, 2020 in a man who arrived from Italy. Two weeks after the first case, there was an exponential increase in the number of cases. The incidence peaked in the 19th week of the year, followed by a steady decline, lasting 16 weeks. Objective. To investigate the level and structure of population immunity to the SARS-CoV-2 virus among the population of Moscow against the background of the incidence of COVID-19. Patients and methods. The study of population immunity of Moscow residents to SARS-CoV-2 was carried out in the period from July 1, 2020 to July 30, 2020 against the background of stabilization of the incidence rate. The work was conducted as part of the first stage of the Rospotrebnadzor project to assess population immunity to the SARS-CoV-2 virus among the population of the Russian Federation, taking into account the protocol recommended by WHO. Volunteers for the study were selected by the method of questioning and randomization. The results of the survey of 2688 people were included in the analysis. The number of volunteers in all age groups was 384–385 people. The content of specific IgG to the SARS-CoV-2 nucleocapsid was determined by the enzyme-linked immunosorbent assya using a kit produced by FBIS SRCAMB according to the manufacturer's instructions. Results. During the survey of volunteers it was found that the share of seroprevalent residents of Moscow was 22.1%. By age groups, the highest proportion of seroprevalent was found among children aged 14–17 years (44.6%), the lowest (15.9%) – among people aged 18–29 years. Seroprevalence had no gender differences. The lowest level of herd immunity was revealed in the North-Western Administrative District (16.8%), the highest – in the South-Eastern Administrative District, as well as in the Troitsky and Novomoskovsky Administrative Districts of Moscow (in both, 24.1%). The smallest number of seropositive persons was among cultural workers (5.8%), the largest – among medical workers (27.0%). In the presence of contacts with patients with COVID-19, the probability of seroconversion increases by 1.5 times, and among convalescing persons COVID-19 antibodies were detected in 60.0% of cases. The proportion of people with asymptomatic infection among seropositive residents was 82.4%. Conclusion. The results obtained make it possible to characterize the population immunity of Moscow residents and are essential for the planning and implementation of anti-epidemic measures during the incidence of COVID-19. Key words: coronaviruses, SARS-CoV-2, seroprevalence, population, COVID-19

Aim of research. To identify the features of the course of cryptosporidiosis, to improve methods of laboratory diagnosis and treatment. Patients and methods: 266 patients of the infectious hospital were observed. To find out oocysts of Cryptosporidia were used: classical microscopic method of modified coloration of fecal swabs according to Tsiol-Nielsenus with the following study in immersion microscopy; the qualitative determination of antigens by the RINA QUICK Cryptosporidium pavrum immunochromatographic test; Immunological analysis (Cryptosporidium Antigen (Stool) ELISA). The intestinal microfiora was studied for dysbacteriosis (Standard for managing patients with intestinal dysbacteriosis (N. M. Gracheva et al., 2004). In complex treatment of 33 patients was used sporobacterin 2 ml twice a day for 10 days. Results. In 26.3 % of patients with infectious diseases, cryptosporidia was found. In 94.3 % of cases, the latent flow was diagnosed, and in 5.7% the intestinal form. In acute period all patients had dysbacteriosis of the intestine of 2-3 degrees. After treatment, there was a positive dynamics in the microbiocenosis of the intestine, which manifested as an increase in the number of patients with minor disturbances in the microfiora (DI 1 25.7 %). Conclusion. When 266 patients were examined, in 26.3 % of cases, oocysts cryptosporidia were found. In the clinical picture, intestinal forms with a latent course dominated against the background of pronounced dysbiotic disorders (DI2-DI3). The inclusion of sporobakterin in the complex therapy of patients had a positive clinical and microbiological effect.

It is recognized the leading role of H. Pylori in the etiology and pathogenesis of diseases of the gastrointestinal tract, it is established morphological features of changes in the mucosa at mono - infection. However, lesions of the stomach may have mixed infectious character, changing the course of the main disease. The aim of research is to investigate the statement of the mucous membrane in its contamination with H. Pylori, Fungi of the species Candida, cryptosporidium in patients with irritable bowel syndrome. Biopsies of the mucous membrane of different stomach parts were studied, using conventional methods of dyeing with further evaluation of the results. Pathological changes in the stomach mucosa were depended on the localization of the process, the measure of contamination, and the presence of various life forms of pyloric Helicobacter whereas cryptosporidium and fungi of the species Candida (non - invasive form) did not influence essentially.

Aim. To study the clinical features of pertussis in adults.Subjects and methods. The clinical manifestations of pertussis in adults were analyzed in 62 patients treated in the Core Unit and Obstetric Unit, Clinical Infectious Diseases Hospital One, Moscow Healthcare Department, in 2011-2013.Results. Investigations conducted in the familial foci of pertussis showed that its incidence rate was 23.7 and 10% in adults and in pediatric institutions, respectively. The source of infant infection was adults in almost one third of cases, mothers in 72% and fathers in 27.7%. Assessment of the symptom complex of pertussis in the sick mothers in the observed period ascertained that 94+/-3% had experienced the typical form of whooping cough: 72.0+/-6.7 and 22.0+/-5.3% had its mild and moderate forms, respectively. The disease had run a latent course in 6+/-3% of the patients. The paper describes cases of pertussis in 5 pregnant women admitted to the obstetric unit for complaints of persistent cough. The diagnosis of whooping cough in all the cases was based on clinical and epidemiological findings and serological tests showing specific IgA and IgG antibodies. Three and two patients experienced moderate and mild pertussis, respectively.Conclusion. Pertussis now remains one of the infectious diseases relevant not only to a pediatric population, but also to an adult one. Adult pertussis maintains the main clinical features typical for this infection with a predominance of its mild forms, which makes its diagnosis difficult. A serological test (enzyme immunoassay) is of high diagnostic value for verifying whooping cough in adults under the present conditions.

Aim. To identify pathologic features of the colonic mucosa in patients with chronic post-parasitic colitis. Methods. Under the observation were 80 patients aged 38-42 years (38 men and 42 women) 1.5-2 years after undergoing parasitic diseases (amebiasis, giardiasis, diphyllobothriasis). In 19 patients due to the presence of dyspeptic phenomena colon mucosa was evaluated by morphometric parameters using grid of Avtandilov. The control group consisted of 6 patients with adaptive norm, in which by complex evaluation (bacteriology, parasitology, endoscopic, histologic) the pathology has not been revealed. Biopsies of colon mucosa were fixed in 10% neutral formalin solution and embedded in paraffin. Histological sections were stained with 1% aqueous solution of Alcian blue, Mayer’s hematoxylin and eosin; for morphometric analysis of 24 objective indicators - azure II-eosin by Romanovsky, with eosin methylene blue and thionine by Nicolas. Results. It was found that the mucosa in chronic post-parasitic colitis in all cases different from the normal colonic mucosa by registered parameters: the amebiasis - in 50% of cases, giardiasis - in 54.1%, with difillobotriosis - in 70.8%. In post-difillobotriosis colitis the number of fibroblasts in the lamina propria was reduced. Post-lyambliotic colitis characterized by hypertrophy of the surface epithelium and a high mitotic activity of the epithelium of intestinal glands. Conclusion. After undergoing parasitic diseases, in the colon mucosa preserved histological changes corresponding to chronic ulcerative colitis; post-amebiasis chronic colitis characterized by catarrhal-haemorrhagic inflammation, chronic post-lyambliotic - catarrhal-follicular, post-difillobotriosis - catarrhal-haemorrhagic inflammation with high activity of the pathological process and moderate atrophy of the intestinal glands.

Comparative researches have been performing since 1990th years, and were devoted to the study of the interrelationship ofserotype landscape of circulating B.pertussis strains with the severity of clinical course of whooping cough. The researches performed in the 2000th years, showed that in patients with identified strains of B.pertussis serotype 1.0.3, the proportion of children with heavy forms of an illness, in comparison with the 1990thyears considerably increased, reaching 43,2±5,0%, against 18,6±3,6. The analysis of the dependence of clinical picture manifestations of whooping cough from the genotypes of B.pertussis has been performed in 83 patients, among them children at the age up to 1 year (77,1±4,6% ofpatients) prevailed. Genotyping of strains of B.pertussis was carried out with the help of two schemes of multilocus antigen sequence typing (MAST1 and MAST2). As a result of the study of the influence of genotypic properties of B.pertussis strains on clinical manifestations of an infection the most severe course of disease was established to be caused by strains of B.pertussis of genotypes 932 MAST1, 319 MAST2 and 329 MAST2. In work there is presented the careful analysis of symptomatology of the prodromal period and the spasmodic cough, performed in 2 groups of children with the severe and moderate form ofwhooping cough. In whooping cough caused by B.pertussis strains of genotypes 932 MAST1, 319 MAST2 and 329 MAST2, there are most pronounced symptoms determining the severity ofthe course of infection.

homosexual men in Europe // J. Med. Virol. – 2007. – Vol. 79, N 4. – P. 356–365.27. Valenzuela M. T., Jacobs R. J., Arteaga O. et al. Cost-effectiveness of universal childhood hepatitis A vaccination in Chile // Vaccine. – 2005. – Vol. 23, N 32. – P. 4110–4119.28. Verhoef L., Boot H. J., Koopmans M. et al. Changing risk profile of hepatitis A in The Netherlands: a comparison of seroprevalence in 1995–1996 and 2006–2007 // Epidemiol. and Infect. – 2011. – Vol. 139, N 8. – P. 1172–1180.29. WHO Fact sheet # 328: Hepatitis A. May 2008. Web March 07 2012. .

The aim of the study is to present a comparative assessment of some invasive and noninvasive diagnostic techniques of Helicobacter pylori. Materials and methods. Helicobacter pylori has been diagnosed on 283 gastrobioptates obtained for diagnosis purposes in 113 patients with chronic gastroduodenitis using invasive (histology, histobacterioscopy, urease Helpyl-test) and noninvasive (respiratory Helic-test, "GastroPanel" immunoenzyme test system) techniques. Helicobacteriosis was verified by histobacterioscopy in 95.3% of cases, by Helpyl-test in 83.6%, by Helic-test in 63.2% and by "GastroPanel" test system 87%. The involvement of antral part of the stomach using histological technique has been revealed in 59.7% of patients, and by "GastroPanel" test system in 36.6%. The changes in gastric fundus have been diagnosed by histological technique in 20.5% of patients, and by "GastroPanel" test system in 17.6%. Conclusion. Among noninvasive techniques the most promising one is "GastroPanel" test system, and in a less degree urease respiratory Helic-test; and from invasive techniques Helpyl-test and histobacterioscopy. The data received can be used in quick H. pylori diagnosis, early treatment in a noninvasive form of chronic gastritis verification.

Нistopathological and gistobakteriological methods studied 178 biopsies of mucosa antrum and fundus of the stomach, obtained from 100 patients with «chronic gastroduodenitis». It was established that various vital forms of pyloric helicobacter (twisted, rod-and coccus) cause one type of chronic helicobacter gastritis, but different activity of the pathological process.

The histology, gistobacterioskopic and urease Express-metods (Helpil-test and Helic-test) studiend 272 biopsies of the mucous membrane of different pars of the stomach and duodenum. Have it established that the pyloric 4 helicobacter in gastrobiopsis is histological verified in 95,9 %, by the urease Helpil - test in 83,6 % and by the urease Helik-test only in 63,2%.

AIM Frequency of occurrence detection of C4A and C4B complement system deficiency in patients with chronic gastrointestinal tract (GIT) diseases including gastric ulcer (GU) and duodenal ulcer (DU). MATERIALS AND METHODS 74 patients with chronic GIT diseases were examined. Endoscopy with stomach mucosa condition evaluation based on histobacterioscopic examination of gastroduodenal biopsy samples was used. Intestine microbiocenosis evaluation was performed by using microflora degree of manifestation according to Federal Standard of Russian Ministry of Health No 231 -91500.11.0004-2003. C4A and C4B isotypes in blood sera of patients were measured by using enzyme immunoassay. RESULTS Chronic gastroduodenitis was diagnosed in 35.1%, pangastritis B--in 41.9%, GU and DU--in 23% of patients. Histological evaluation of biopsy samples revealed marked inflammatory changes in stomach and duodenum mucosa in 77% of patients. Stomach mucosa infection rate by Helicobacter pylori reached 85%. Microbiological disorders manifestation in microflora of patients matched endoscopic and histobacteriscopic changes in it and was the highest for GU and DU. In 76.0% of cases C4A and C4B isotype deficiency in blood sera matches the development of erosive-ulcerous process in stomach and duodenum mucosa with marked background dysbiotic GIT microbiota disorders. CONCLUSION Patients with functional deficiency of C4A and C4B isotypes have a genetic burden to susceptibility to chronic GIT diseases whereas H.pylori infection deteriorate the disease.

Нistopathological and gistobakteriological methods studied 178 biopsies of mucosa antrum and fundus of the stomach, obtained from 100 patients with «chronic gastroduodenitis». It was established that various vital forms of pyloric helicobacter (twisted, rod-and coccus) cause one type of chronic helicobacter gastritis, but different activity of the pathological process.

The intestines dysbacteriosis, along with other factors (high acidity, environment factors stresses, smoking, food errors, etc.) takes part in development and current of chronic diseases of a gastroenteric path associated with pyloric helicobacter. There was marked the expressed dependence between the degree of disbiotic changes, a phase and a character of morphological infringements caused by helicobacter, namely gastritis and duodenitis. The expressed changes of microbiocenosis can remain in a mucous membrane of a stomach and a duodenal gut after carrying out successful eradication of therapy, regarding cases even to amplify.

The histology, gistobacterioskopic and urease Express-metods (Helpil-test and Helic-test) studiend 272 biopsies of the mucous membrane of different pars of the stomach and duodenum. Have it established that the pyloric 4 helicobacter in gastrobiopsis is histological verified in 95,9 %, by the urease Helpil test in 83,6 % and by the urease Helik-test only in 63,2%.

A protease activity may be determined by means of immunoglobulins. Since proteolytic products apparently do not retain antigenic determinants of the initial substrate, the monitoring of enzymatic process may employ ELISA methods. The ELISA determination of functional activity of specific IgA1 protease has been used not only for detection of this enzyme, but also for measurement of its inhibition constants. IgG adsorbed onto a microplate was used for evaluation of total proteolytic activity. Varying pH values of the reaction medium it is possible to measure activity of neutral, alkaline and acid proteases. This approach was used for estimation total proteolytic activity of neutral proteases in blood serum. Due to high sensitivity of this method it was possible to dilute serum up to the level when serum inhibitors had not blocked enzyme activity. Assay of serum enzyme activity at acidic pH results in activation of pepsinogens and determination of pepsin activity. Measurement of a total level of serum pepsinogen activity may have diagnostic importance in gastroenterology, due to decisive contribution of pepsinogen I to the detectable activity.

The problem of constructing means of correction of gastrointestinal microflora is utterly important. The most promising direction here seems to be construction of synbiotics containing a multiprobiotic complex of bifidobacteria and lactobacilli, modeling the microbiocenosis of a certain age group, inulin, as a prebiotic factor and a vitamin and mineral complex. The aim of the study was to evaluate the biologically active food supplement "Normospectrum" vs. the commercial preparation "Bifidumbacterin", its ability to correct the intestinal microflora and the functional condition of the gastrointestinal tract in children. "Normospectrum" was well tolerated, favored regression of the main clinical manifestations, and had positive effect on the intestinal microbiocenosis, increasing the proportion of bifidobacteria, lactobacilli and escherichiae with full enzymatic activity, and lowering the proportion of conditionally pathogenic bacteria and fungi in the intestinal tract. The effects of "Normospectrum" on the functional disturbances of the gastrointestinal tract and the intestinal microflora were much more profound than those of "Bifidumbacterin". Good tolerance and positive effects of the new probiotic preparation "Normospectrum" on the intestinal microbiosis allows recommending it for broad clinical application in children when correction of dysbiotic shifts in the intestinal microflora is necessary.