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Norovirus infections are a leading cause of acute gastroenteritis worldwide in persons of all age groups. Despite the broad genetic diversity, norovirus GII.4 has predominated during the past 20 years [...]

Introduction: The novel SARS-CoV-2 coronavirus, which emerged at the end of 2019 and caused a worldwide pandemic, triggered numerous questions about the epidemiology of the novel COVID-19 disease and  about wellknown coronavirus infections, which used to be given little attention due to their mild symptoms., The Purpose: The routine screening-based multiyear retrospective observational study of prevalence and circulation patterns of epidemic-prone human coronaviruses in Moscow., Material and Methods: The real-time polymerase chain reaction was used to detect RNA of human coronaviruses (HCoVs) in nasal and throat swabs from 16,511 patients with an acute respiratory infection (ARI), aged 1 month to 95 years (children accounted for 58.3%) from January 2016 to March 2020, and swabs from 505 relatively healthy children in 2008, 2010 and 2011. Results. HCoVs were yearly found in 2.6-6.1% of the examined patients; the detection frequency was statistically higher in adults than in children, regardless of sex. At the height of the disease incidence in December 2019, HCoVs were detected in 13.7% of the examined, demonstrating a two-fold increase as compared to the multi-year average for that month. The statistical frequency of HCoV detection in ARI pediatric patients under 6 years was significantly higher than in their healthy peers (3.7 vs 0.7%, p = 0.008)., Conclusion: HCoVs circulate annually, demonstrating a winter-spring seasonal activity pattern in the Moscow Region and reaching peak levels in December. Over the years of observation, the HCoV epidemic activity reached maximum levels in December 2019-February 2020 and decreased in March to the multi-year average. Amid a growing number of SARS-CoV-2 cases imported to Moscow in March 2020, the HCoV detection frequency dropped sharply, which can be explained by the competition between different coronaviruses and by the specificity of HCoV detection with the diagnostic test kit used in this study.

Aim: Determine features of epidemic process (EP) of Sonnei dysentery in Khabarovsk Region in 2012 - 2014 due to atypical causative agent., Materials and Methods: Detailed characteristics of 161 cultures of Shigella sonnei isolated from 81 patients from epidemic focus in children boarding school in Bikin as well as from 22 patients from sporadic and group foci of dysenteryin Khabarovsk (biochemical type, colicin-genotype, spectrum of drug resistance) is given. Molecular-biologic subtyping was carried out for 11 strains by Pulsed Field Gel Electrophoresis method (PFGE)., Results: Materials of observation of a prolonged foci of Sonnei dysentery with contact-domestic transmission route of the infection in children boarding house for disabled (October 2012 - September 2014) are presented. The diseases are etiologically connected with atypical mannitol- negative types of shigella isolated for the first time in 40 years of observation in Khabarovsk region. Epidemic process of shigellosis was supported by prolonged carriership of the causative agent in patients and special contingent ofthe nursing home. Shigella cultures isolated in the focus belonged to the same colicin-genotype and 2 distinct drug resistance clones, but a single genotype established by PFGE method., Conclusion: Results of the studies give evidence on the importance of determi- nation of traditional phenotypic and contemporary genotypic variants of shigella and the neces- sity of search for arguments, additional methodic approaches for establishing similarities and differences of shigella isolates from within the same outbreak of the diseases as well as for com- parison of strains circulating in different territories.

The data of seasonal monitoring are presented concerning antigen types of rotaviruses group A circulating on the territory of the Russian Federation in the periods of seasonal uprising of morbidity in 2011-2015. Annually, the study included from 10 to 12 subjects of the Russian Federation with annual testing from 444 to 728 samples from children aged younger than 5 years with acute infection diarrhea. In the seasons of 2011-2012, 2012-2013, 2013-2014, 2014-2015 the most prevalent [P] G types of rotaviruses correspondingly made up to: G4[P]8 -50.2%-36.5%-43.8%-1.6%; G1[P]8 - 26.6%-14.3%-27.3%-22.5%; G3[P]8 - 4.4%-23.7%-4.2%-2.0%; G9[P]8 - 4.3%-5.3%-10.1%-7.1%; G2[P]4 - 7.7%-7.9%-9.0%-3.1%. The expressed territorial irregularity of prevalence of antigen types of retroviruses was observed., Competing Interests: The authors declare no conflict of interest.

The study was carried out to evaluate and compare analytical characteristics of reagents kits for identification of antigens of rotaviruses SD BIOLINE Rotavirus (Standard Diagnostics, Korea), RIDA Quick Rotavirus (R-biopharm AG, Germany), RotaStick One-Step Test (Novamed Ltd., Israel), QuickStripe Rotavirus (Savyon doagnostics Ltd., Israel), Rotavirus-antigen-IFA-BEST (Vector-Best, the Russian Federation), Rota-antigen (NPP AKVAPAST, the Russian Federation). The panel included 84 positive and 43 negative samples of rotaviruses group A according their content. The reagents kit "Amplisense OKI screen-FL" with confirming [P]G typing of positive samples was used for comparison. The comparison of analytical sensitivity of reagents kits was implemented on panel characterized by using technique of droplet digital polymerase chain-reaction. The indicators of diagnostic sensitivity and specificity of reagents kits amounted to 84.52% and 100%for SD BIOLINE Rotavirus and RIDA Quick Rotavirus, 71.43% and 100% for RotaStick One-Step Test, 75.00% and 100%for QuickStripe Rotavirus, 83.33% and 100% for Rotavirus-antigen-FA-BEST, 83.33% and 100%for Rota-antigen. The analytical sensitivity of immunochromatographic and immunoenzyme kits amounted to 5 x 106 GE/ml for [P]8G4 genotype of rotaviruses of group A. The reagents kits SD BIOLINE Rotavirus, RIDA Quick Rotavirus and Rotavirus-antigen-IFA-BESTdemonstrated matched high indicators of diagnostic sensitivity and specificity sufficient for etiological diagnostic of rotavirus infection at acute stage of disease. The analytical sensitivity of compared kits does not allow recommending them to apply in analysis of samples characterized by lower concentrations of rotaviruses (asymptomatic agents, objects of environment).

Aim: To evaluate the practical efficiency of the diagnostic algorithms for enterohemorrhagic escherichiasis, which are laid down by the current normative documents of the Russian Federation., Subjects and Methods: The investigators estimated the prevalence of enterohemorrhagic Escherichia coli (EHEC) infection in children with the symptoms of acute enteric infections (AEI) (archival samples) and in those aged less than 5 years with fatal evolution and a history of diarrhea and hemolytic uremic syndrome (HUS), evaluated the efficiency of bacteriological tests in HUS patients with acute EHEC infection, and comparatively analyzed the documents regulating EHEC surveillance in the Russian Federation and other countries., Results: Nucleic acid amplification assay showed that the prevalence of EHEC among the hospitalized children was 1.2% (27/1269), the anamnestic registration rate for HUS among the children with fatal outcomes in AEI was 20% (5/25). The efficiency of the bacteriological diagnosis of enterohemorrhagic escherichiasis in the archival samples corresponding to the early stages of the disease in the presence of diarrhea and at the HUS development stage was 48.1% (13/27) and 6.1% (2/33), respectively. There was a potential to enhance the efficiency of the normative documents regulating the etiological diagnosis of EHEC infection in the Russian Federation., Conclusion: The given data substantiate the necessity of including the etiological diagnosis of EHEC infection in the list of mandatory screening studies in children with sporadic cases of hemocolitis at the early stages of the disease.

The astroviral infections are considered among the most common pathogens of gastroenteritis in children. The incidence, molecular epidemiology and clinical manifestations of the astrovirus infection in children hospitalized with acute gastroenteritis, in various areas of the Russian Federation from 2004 to 2010 was determined.

The paper presents the results of etiological interpretation of the outbreak of Escherichia coli O157-induced enteric infection complicated by hemolytic uremic syndrome in Omsk in spring 2009. Seventeen infants aged 5 months to 2.5 years were examined; of them 9 patients were on hemodialysis. The diagnosis was verified in 7 children, by isolating verotoxin after fecal enrichment on the concentrating nutrient RIDA Enrichment Bouillon medium containing bile salts and mitomycin C, E. coli O157:H7 cultures on the sorbitol medium and/or by identifying E. coli O157 DNA. Six (4 having verotoxin) infants were found to have rotavirus and noro-virus antigens or DNA/RNA, which may make a contribution into the development of mixed infection and increase the risk of complications.

Aim: To determine the role of noroviruses in the rise of hospital outbreaks of acute intestinal infections (AII), to study clinical and epidemiological aspects of hospital noroviral infection., Material and Methods: Routine diagnostic methods and diagnostic tests on the base of polymerase chain reaction (PCR) were used for identification of group A rotaviruses, noroviruses, astroviruses, adenoviruses, salmonella, thermophilic campilobacteria, shigella, enteroinvasive echerichia (EIEC) in 70 adult patients with AII transferred from general hospital to infection hospital in 2003-2007. A part of the strains was typed with primers specific for genetic cluster G2/4., Results: Routine methods failed to identify causes of hospital infection. PCR detected AII etiology in 77.8% patients. Norovirus of the second genotype (G2) was identified as monoinfection in 87.8% verified cases, in association with other agents--in 12.2%. Typed noroviruses belonged to cluster G2/4. Nosocomial norovirus infection was characterized by winter-spring occurrence and a moderate course., Conclusion: An essential role of noroviruses in hospital AII outbreaks in elderly patients in winter-spring is shown.

Study of the etiologic spectrum of sporadic cases of causative agents of acute enteric infections (AEI) in 753 patients aged 15-85 years old using polymerase chain reaction (PCR) was performed in the infectious diseases hospital during 12 months. It was shown that detection of the causative agents of AEI by PCR was 2.2 times more effective than routine microbiologic diagnostics supplemented with test of feces on rotavirus by ELISA method and allowed to detect etiologic agent in 54.3% of the patients. Viral etiology of AEI was determined in 22.6% of the patients. The most significant causative agents of AEI comparable on the rate of detection with salmonella and shigella were genotype 2 noroviruses and group A rotaviruses which were isolated in 10.4 and 8.9% of the patients respectively. Seasonal change of dominating viral pathogens causing diarrheal diseases was noted: predominance of group A rotaviruses during winter-spring period, noroviruses--during spring-summer months, and astroviruses--during fall and in the beginning of winter.

Aim: To study seasonal and age features of etiological structure of acute intestinal infections (AII) in the territory of the RF., Material and Methods: A total of 7388 AII inpatients aged from 1 day to 90 years from 7 cities (Moscow, St-Petersburg, Nizhniy Novgorod, Chelyabinsk, Tyumen, Makhachkala and Khabarovsk) of the RF participated in a trial conducted from December 2001 to September 2006 The patients were examined with diagnostic tests based on polymerase chain reaction (PCR) for detection of rotaviruses of group A (RVA), noroviruses, astroviruses, adenoviruses, salmonella, termophilic campilobacteria, shigella and enteroinvasive Escherichia coli (EIEC)., Results: The above agents were detected in 72% children and 52% adults. In children RVA and noroviruses occurred most frequently (29.5% and 11%, respectively). The adults carried most often salmonella (9.3%), noroviruses (8.4%), RVA (7.8%) and Schigella in combination with EIEC (7.0%)., Conclusion: Viral agents are essential or prevailing causative agents of AII at different ages. Seasonal and age-related trends of AII morbidity are characterized.

Aim: To describe clinical symptoms of sporadic cases of noro- and astroviral infection in adults; to compare a clinical picture and a course of rotaviral infection (R VI), noroviral infection (NVI) and astroviral infection (A VI)., Material and Methods: Reverse transcription and polymerase chain reaction (RT-PCR) method was used to examine fecal samples from 1032 patients with acute intestinal infections (All) at the age of 15 to 90 years admitted to the infectious department of the clinic of Chelyabinsk State Medical Academy in 2004-2005. Detectability and severity of some symptoms in R VI, NVI and A VI patients were analysed and clinical manifestations of viral intestinal monoinfections were compared., Results: Monoinfection was diagnosed in 230 (22.3 %)fecal samples: RVI (n = 101), NVI (n = 100), A VI (n = 29). Sporadic morbidity was the highest from March to May, March to September, October to December for R VI, NVI and A VI, respectively. Gastroenteritis syndrome was prevalent in all the infections studied. Diarrhea with marked dehydration was more typical for RVI, dyspepsia and abdominal pain--for NVI. Intoxication occurred with the same frequency in all the infections. Severe RVI ran with normal body temperature in many patients over 60 years of age., Conclusion: Viral diarrheal diseases are frequent in adults of all ages and run with similar clinical picture. The most serious course of the infection with most severe syndromes of gastroenteritis and dehydration was typical for RVI. Etiological nature of viral intestinal infections can be established only with laboratory diagnostic methods.

Sapoviruses were found, for the first time, to be circulating in children with acute gastroenteritis in the city of Moscow. On the basis of a genetic analysis, they were classified as belonging to genotypes 1 and 2. Two groups of sapoviruses that are essentially different from the strains presented now at the GenBank NCBI were described within the case study.

Aim: To develop a diagnostic kit for detection of SARS (severe acute respiratory syndrome)-related coronavirus RNA based on reverse transcription and polymerase chain reaction and to estimate its specificity and sensitivity., Material and Methods: 68 virus and bacterial cultures, 240 clinical samples from people without SARS symptoms and also 22 RNA samples from patients with SARS symptoms received during the epidemic in Beijing were used., Results: The specificity of the kit was determined using animal coronaviruses and other bacterial and viral strains, causing acute respiratory and intestinal infections, and was shown to be 100%. The sensitivity of the kit in different clinical samples was 2.2 x 10(3) genome equivalents of recombinant SARS RNA in 1 ml of the specimen. The kit was evaluated in the Institute of Microbiology and Epidemiology of Beijing (China) using SARS-cov viral suspension and clinical samples from patients with suspected SARS. It was shown that kit was able to detect 10 TCID/50 ml of SARS-Cov virus. Testing of clinical samples from patients with suspected SARS showed that diagnostic sensitivity of the kit was 95%. Detection of the SARS-Cov RNA was more effective in feces compared to sputum 990 and 40%, respectively)., Conclusion: The kit "AmpliSens SARS" for qualitative detection of SARS-related coronavirus RNA by reverse transcription and polymerase chain reaction (PCR) in nasopharyngeal wash/aspirates, naso/oropharyngeal swabs, plasma, and extract from feces has been developed in the Central Research Institute for Epidemiology of the RF Ministry of Health. The kit contains reagents for RNA isolation and purification, cDNA synthesis by reverse transcription of RNA, for PCR and for electrophoretic analysis of amplified products. The kit also contains recombinant positive and internal control samples allowing to control efficiency of analysis and showed good analytical and diagnostic characteristics.