Phylogenetic analysis and molecular genetic characteristics of West Nile virus lineage 2 isolates circulating in the Russian Federation.

Since its initial detection in Africa, the West Nile virus has disseminated widely across all continents, becoming endemic in numerous countries, including the Russian Federation. A substantial expansion of the West Nile virus range was observed in the European part of the Russian territory in 1999. In light of this epidemiological trend, research endeavours focusing on monitoring West Nile virus circulation activity in endemic regions of the country have gained paramount significance. A substantial dataset has been accrued from 2007 onwards regarding genomic variability and dissemination dynamics across the country throughout the entire monitoring period for the West Nile fever pathogen. The objective of this study was to characterise West Nile virus isolates that have been circulating in the Russian Federation and identify their molecular and genetic characteristics. A phylogenetic analysis of 55 complete genome sequences revealed that the West Nile virus population within the Russian Federation is genetically heterogeneous and is represented by four major clades. One of these clades is currently exhibiting extensive spread into new regions of the country.

[THE COMPARATIVE CHARACTERISTIC OF SETS OF REAGENTS FOR IDENTIFICATION OF ANTIGENS OF ROTAVIRUSES USED ON THE TERRITORY OF RUSSIA].

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).

[THE INTERPRETATION OF RESULTS OF DETECTION OF AGENTS OF VIRAL DIARRHEA IN REAL-TIME MODE].

The study was carried out to establish values of parameters characterizing concentrations of pathogens (threshold cycle - Ct) correlating with acute phase of viral gastroenteritis. The groups of patients with sporadic and group morbidity of acute intestinal infections were examined. The reagents kits Amplience (The central research institute of epidemiology, Russia), in real-time format polymerase chain reaction were applied to detect Rotavirus grA, Norovirus GII, Astrovirus, Adenovirus grF, Shigella spp, EIEC, Salmonella spp, Campylobacter spp (thermophilic group).The analysis was applied to distribution of Ct depending on isolated and combined detection ofpathogens in clinical samples. The evaluation was implemented concerning effect on Ct values of both inhibitors of polymerase chain reaction contained in feces and application of various amplifiers such as Rotor-Gene Q (QIAGEN, Germany), CFX96 (Bio-Rad, USA), "DT-96" (DNA technology, Russia). The risks of cross contamination during carrying out of investigations are evaluated. The asymmetric or bi-modal character of distribution of Ct values related to cases of combined detection of several pathogens is established. The following indicators are established common for patients with mono-infections (Ct mean ± SD): Rotavirus grA (Ct 20.63 ± 6.35; n = 978), Norovirus GII Astrovirus (Ct 21.06 ± 6.54; n = 54), Adenovirus grF (Ct 8.42 ± 2.4; n = 42). The corresponding values for victims of infective episodes amounted to Norovirus GII (24.19 ± 5.29; n = 447) and Rotavirus grA (18.65 ± 4.16; n = 50). The recommendations are presented concerning practical interpretation of results of real-time polymerase chain reaction. The indirect characteristic of content of pathogens in samples of clinical material derived from real-time polymerase chain reaction provides important information about association of pathogen with acute phase of disease. The high informativeness of given type of investigations support possibility of its effective implementation not only doing etiologic diagnostic but also in case of isolation of pathogen in clinically healthy individuals and examination of objects of environment.

Interaction of plum pox virus with specific colloidal gold-labeled antibodies and development of immunochromatographic assay of the virus.

Two monoclonal antibodies (mABs) raised against plum pox virus (PPV) were shown to recognize its D, M, and C strains. Conjugates of the antibodies with colloidal gold (CG) nanoparticles averaging 26 nm in diameter were synthesized. The binding constants of PPV with both the native and conjugated mABs were determined using a Biacore X device. The complexes between the CG-mAB conjugates and plum pox virions were examined by means of transmission electron and atomic force microscopy. Using the conjugates with optimal component ratio, an express immunochromatographic assay of PPV was developed with a detection limit of 3 ng/ml and duration of 10 min. The assay was tested for PPV detection in samples of stone fruit tree leaves and demonstrated a good compatibility with the data obtained by "sandwich"-ELISA. The developed assay can be used in the field and applied for monitoring viral infection and for quarantine purposes.

[Effect of use of bone marrow cells in therapy for experimental tuberculosis].

The authors studied the efficiency of use of bone marrow cells in the treatment of experimental tuberculosis. Bone marrow cell transplantation to H37Rv tuberculosis-infected H37Rv mice was shown to prolong the life span in the animals as compared to untreated animals. Examination of humoral immunity indicated that administration of allogenic bone marrow cells resulted in the nonspecific polyisotypic stimulation of antituberculosis antibodies, which is essential in producing the protective humoral background. A more significant generation of IgG2a antibodies than that of IgG1 antibodies was also found in therapy with bone marrow cells, which pointed to the fact that there was a Th1 response that is obviously protective in tuberculosis. The high level of IgG2a antibodies correlated with the high specific cellular immune response estimated by the delayed hypersensitivity reaction.