The aim of the study was to analyze genetic characteristics of strains belonging to group A rotaviruses (RVA) circulating in Moscow in 2015–2020, including rare strains non-typeable by polymerase chain reaction (PCR).Materials and methods. A total of 289 stool samples were tested; the samples were collected from children aged 1 month to 17 years, hospitalized with acute gastroenteritis. Immunochromatography and real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) assays were used for detection of rotaviruses in the samples. The rotavirus genome sequencing was performed using the Sanger technique and nanopore sequencing.Results and discussion. RVA RNA was detected in 131 clinical samples, and the G/[P] genotype was identified in 125 samples. The general profile showed prevalence of RVA strains with the G9P[8]I1 genotype (37%) followed by G3P[8]I2, G4P[8]I1, G2P[4]I2, G1P[8]I1, and G3P[8]I1 variants (18, 15, 11, 5, and 2%, respectively). Seven (5%) isolates were identified as GxP[8]. In 2015–2020, the region reported a decline in G4P[8]I1 genotype prevalence (from 39% to 9%) and an increase in the proportion of the G9P[8]I1 genotype (from 6% to 37%) as compared to 2009–2014. In 2018–2020, a large number of cases with the previously unknown DS-1-like reassortant strain with the G3P[8]I2 genotype were reported; the above strain has become widely common worldwide in the recent years. Nanopore sequencing was performed to analyze the genome of the G3P[8]I2 strain and the rare G4P[6]I1 strain. It was found that the G4P[6]I1 strain was phylogenetically related to porcine rotaviruses.Conclusion. In the recent years, the genetic diversity of RVA circulating in the Moscow Region has changed significantly. The obtained results prove the importance of continuous monitoring of rotavirus infection and selective sequencing of RVA genes to fine-tune data of the type-specific real-time RT-PCR. The ever-changing genetic composition of the circulating RVA strains calls for regular optimization of RVA genotyping systems based on real-time RT-PCR.

Introduction. Acute gastroenteritis (AGE) is one of the leading causes of pediatric morbidity and mortality. The use of cytomuco-protectors that stabilize the intestinal barrier can increase the effectiveness of treatment.The aim is to determine the gelatin tannate (GT) clinical efficacy, safety and antiviral activity in AGE in children admitted to the hospital.Materials and methods. An open, prospective, randomized study included 52 children <7 years of age with AGE. The intervention group (n = 28) received GT, which was administered orally at 250 mg to children <3 years of age and 500 mg to children £ 3 years of age 4 times a day for 7 days. The severity of AGE (Vizikari scale: 10-14 points and CDC: 1-5 points) in parallel groups was significant. Standard treatment included rehydration and probiotic B. bifidum 1 (15 * 108 CFU / day in three divided doses). Antibiotic therapy (ABT) was received by 50% of children from each group. Fecal samples at screening and on the 7th day of treatment were examined in Real-time PCR with the determination of nucleic acids of rotaviruses A, noro-, adeno-, astro- and enteroviruses. The viral etiology of AGE was confirmed in 53.8%, salmonellosis - in 3.8% and campylobacteriosis - in 1.9% of patients.Results. GT reduced the risk of diarrhea on day 5 by 32% [95% confidence interval 14-50%] OR 0.25 [0.11-0.25] and by 14% [4-24%] by day 7. In the GT group, on day 7 of treatment, all patients had normal stool consistency. GT reduced the time for stool normalization by 1.3 days [0.2-2.3]. A more significant effect was obtained in patients with risk factors for insufficient treatment efficacy and in patients with inflammatory AGE requiring ABT. In those who received GT, a decrease in the concentration of viruses in feces was found, in the control - no statistical differences. The recurrence of AGE symptoms during hospital treatment was recorded with a frequency of 3.6% and 16.7%, respectively (p = 0.111).Conclusions. GT significantly reduced the risks of incomplete therapy effect by day 7 of treatment and the average positiveness of stool normalization. Trends in the antiviral action of GT and its positive effect on the incidence of nosocomial viruses.

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Results of studies on nutrition of juvenile fishes of the Curonian Lagoon of the Baltic Sea are presented. Material on young-of-the-years nutrition was collected in October 2016 during the expeditions of «AtlantNIRO» at 14 standard stations in the Curonian Lagoon. A total of 418 specimens of young-of-the-years were collected and processed. Juveniles of fishes of the Curonian Lagoon were represented by 10 species: pikeperch, bream, roach, perch, smelt, ruffe, three-spined stickleback, ninespine stickleback, bleak and sabrefish. Planktonic and benthic invertebrates formed a basis of the young-of-the-years diet. In most species of juvenile fishes, the nutritional spectra did not differ from the nutritional spectra in the range. An exception was juveniles of the ruff and ninespine stickleback, in which planktonic crustaceans predominated in the diet, while in other reservoirs they consumed bottom organisms. Only Cladocera and Copepoda were found in the diet of roach of juveniles; bottom organisms were absent. In the range of roach juveniles, bottom organisms and mollusks prevailed. The food similarity indices for juvenile fish in the Curonian Lagoon are quite high, which may indicate a tension in food relations between juveniles and (or) partial or complete overlap of their food niches. The weakening of food competition is ensured by the divergence of daily dietary peaks. Three-spined and nine-spined sticklebacks as well as a sabrefish and sticklebacks have the closest food spectrum. On the contrary, sabrefish and bream have a different food spectrum. The peculiarity of feeding of pikeperch juveniles in 2016 was the lack of transition to predatory nutrition.