Noroviruses are widespread causative agents of acute gastroenteritis (AGE). In recent years, recombinant genotypes of noroviruses, which include RNA-polymerase GII[16], have become globally widespread. The aim of the research was to analyze the genetic diversity of noroviruses circulating in 2016–2021 in the Republic of Belarus in order to establish the contribution of the identified genotypes to the formation of morbidity and to study the features of the circulation of their recombinant variants containing RNA polymerase GII [P16]. Sequencing and genetic analysis of a fragment of the ORF1 / ORF2 genome of 242 noroviruses from patients with AGE collected in 2016-2021 was carried out. It was found that 199 norovirus isolates (82.2% of all identified) were recombinant. During this period, genotypes containing GII.P16 polymerase and the VP1 gene of genotypes GII.2, GII.3, GII.4, GII.12, GII.13 prevailed (143 isolates, 71.9% of all recombinant genotypes). The proportion of individual recombinant genotypes was distributed as follows: GII.4 [P16] - 42.0%, GII.2 [P16] - 32.2%, GII.3 [P16] - 16.8%, GII.12 [P16] - 8.4%, GII.13 [P16] - 0.7%. The genotypes GII.4 [P16] and GII.2 [P16] circulated for the longest time - from 2016-2017 to 2021. Their circulation was accompanied by the emergence of outbreaks of AGE: genotype GII.2 [P16] caused outbreaks in 2016, 2018 and 2021, GII.4 [P16] - in 2017 and 2021. All investigated isolates of different recombinant genotypes contained the same variant of the GII.P16 RNA polymerase gene, which became globally distributed in the world in 2015-2017. Comparison of the nucleotide sequences of isolates within genotypes showed that, despite the long circulation period, there were no accumulation of mutations and no selection of genovariants within the genotype.
Background. Individual cases of viral hepatitis E are recorded in the Republic of Belarus annually indicating the need for the pathogen monitoring at both the population and reservoir levels. Objective. To consolidate the monitoring data on hepatitis E virus over the period of 2018 - 2021, as well as to work out an effective algorithm for its laboratory screening. Material and methods. As part of the study, 345 samples were analyzed, including 227 human biological samples, 37 samples of biological materials of domestic pigs, 22 samples of food and 59 samples of waste water. Results. According to the results of serum diagnostics, in the group of kidney recipients (n = 29), the detection rate of IgM and IgG to hepatitis E virus was 6.9% [0.85%; 23.03%] and 17.2% [7.13%; 35, 02%] respectively; in the group of patients with pregnancy pathology (n = 44) - 6.8% [1.68%; 18.89%] and 11.4% [4.5%; 24.43%] respectively. In patients with acute hepatitis of unknown etiology (n = 26), antiviral IgM was not detected, while the frequency of antiviral IgG detection reached 7.7% [1.02%; 25.26]. In control group (blood donors, n = 53) IgM and IgG were detected in 1.9% [0.6%; 10.88%] and 5.7% [1.35%; 15.97] of those examined respectively. Hepatitis E virus RNA was detected in 8 human biological samples (3.8%) from kidney recipients. The identified hepatitis E viruses were represented by genotype GIII and belonged to a previously unidentified subgenotype (GIIIa - GIIIi). In the studied samples of biological material from pigs, as well as in samples of food and waste water, hepatitis E virus RNA was not detected. Conclusions. An algorithm for hepatitis E virus laboratory screening has been developed and tested. Its section concerning the diagnosis of viral hepatitis E is set out in the Instructions for use "Algorithm for laboratory diagnosis of viral hepatitis E" (No. 148-1220 from January 28, 2021).
An Esсherichia coli 42cpa-c strain synthesizing C-terminal fragment of Clostridium perfringens alpha-toxin was engineered. The strain is distinguished by productive capacity 1.2 mg of target protein per 1 L of cultural liquid. The protein contains octahistidine peptide at C-end of the molecule, enabling to carry out its one-stage purification by metal-affine chromatography on Ni2+-NTA resin. The resulting CPA-C protein preparation is potentially suitable for formulation of the derived vaccine.
Background. The monitoring of enteric viruses in wastewater is a new epidemiological approach allowing to detect the intensity of their circulation in humans. The aim of the study is to conduct and analyze parallel monitoring studies of wastewater and biological material from patients with acute viral intestinal infections (AEI) selected from different regions of the Republic of Belarus in terms of their actual pathogens. Material and methods. 403 samples of wastewater and 381 samples of feces from patients with AEI, collected in different regions of Belarus, were examined by real-time PCR. Results. In patients with AEI, rotaviruses A (20,4%) and noroviruses of the genogroup 2 (10,2%) were most often detected, while adenoviruses F (2,2%), enteroviruses (0,8%) and noroviruses 1 (0,3%) were found quite rarely. Adenoviruses F (25,9%), rotaviruses A (18,4%) and enteroviruses (13,4%) dominated in wastewater samples while noroviruses 2 (6,8%) and noroviruses 1 were detected much less frequently (1,5%). Certain differences were revealed in the percentage of viral AСI pathogens present in patients and those found in wastewater, that indicates active hidden circulation of some of them (adenoviruses F and enteroviruses). SARS-CoV-2 coronavirus was detected in one of the wastewater samples. The conducted sequencing and bioinformatic analysis of its nucleotide sequence showed 100% similarity with the sequences of isolates identifed in patients with COVID-19.Conclusions. The obtained data indicate the potential of the studies based on monitoring of intestinal viruses in wastewater in order to increase the effectiveness of epidemiological surveillance of known AEI pathogens circulation and to identify new and emerging ones.
BACKGROUND This paper presents the results of studying the characteristics of the antibody response in kidney recipients who are at high risk of severe COVID-19. METHOD The study of features of the formation of post-infectious anti-SARS-CoV-2 IgG was carried out in the group of kidney recipients (n = 171) with PCR confirmed diagnosis of COVID-19. Studies of the characteristics of post-vaccination immunity were carried out in a group of vaccinated recipients (n = 49) with Sputnik V (Russia) or Vero Cell (China). ELISA was used to detect IgG to S and N proteins of the SARS-CoV-2. Comparative studies used a simple randomized selection of immunocompetent COVID-19 patients (n = 163). Statistical data processing was carried out using the χ2 and Wald's methods. RESULTS It was found that 30 days after the onset of clinical symptoms of COVID-19 in kidney recipients, IgG to S and/or N proteins of SARS-CoV-2 were detected in 89.5% (83.9%–93.3%) of them. The detection rate of IgG to the S protein was higher than that to the N protein [87.7% (81.9%–91.9%) and 62.0% (54.5%–68.9%), respectively). At the same time, the seroprevalence to the pathogen varied by age: in the 18–34-year-old group it was 77.7% (59.9%–88.9%), in the 50–64-year-old group it was 96.7% (88.2%–99.8%) and in the group >64 years old it was 80.0% (66.8%–89.0%). This trend of antibody production in older recipients correlated with the highest frequency of registration in them of moderate and severe forms [66.7% (56.4%–75.6%)]. Differences due to the severity of the disease were noted both in the frequency of detectable antibodies [80.3% (69.5%–88.0%) in recipients with a mild form of COVID-19 and 96.0% in recipients with a severe form of infection (P < .001)] and in the intensity of the formed anti-SARS-CoV-2 immunity. Thus, high values of PC (positivity coefficient) (>12) to S protein were recorded in 52.7% (39.8%–65.3%) and 63.2% (53.1%–72.2%) patients with mild and severe forms of COVID-19, respectively, which indicated a direct dependence of the production of antiviral antibodies on the severity of the infection. It was found that in 62.6% (55.1%–69.5%) of recovered recipients anti-SARS-CoV-2 IgG persisted for a period of 3 months from the onset of infection. In a significant proportion of recipients [42.8% (35.5%–50.2%)], antibodies were detected for up to 15 months. In general, the post-infectious antibody response in kidney recipients and immunocompetent patients had similar patterns of development. Despite the general mechanism of antibody production, in immunocompetent patients, the frequency of detection of antiviral antibodies (to N protein: 82.9% and to S protein: 91.2%), tension indicators (high values of PC to N protein: 51.0% and to S protein: 75.5%) and the duration of retention (in 50.3% at 15 months of monitoring) were slightly higher than the same parameters in recipients with COVID-19. In kidney recipients after immunization with Sputnik V and Vero Cell (n = 34), a rather low detection rate of antiviral IgG [52.9% (36.7%–68.6%) compared with a similar parameter (P < .001) in vaccinated immunocompetent individuals [96.8% (94.8%–98.1%)] was found. The seroprevalence in the group of recipients with hybrid immunity (after illness and vaccination, n = 15) was 86.7% (60.9%–97.5%). In a comparative analysis of the intensity of post-vaccination immunity, high values of PC to S protein (>12) were recorded in 44.0% (26.7%–62.9%) of recipients vaccinated with Sputnik V and 50.0% (31.4%–68.6%) of recipients vaccinated with Vero Cell. The inverse relationship was observed in immunocompetent individuals: 64.7% (58.1%–70.7%) for Sputnik V and 44.2% (36.8%–51.8%] for Vero Cell. CONCLUSION The patterns of antibody response to the causative agent in recipients with COVID-19 are comparable to those in immunocompetent patients, while for vaccinated recipients, a low frequency of detection of antiviral antibodies was shown, which indicates the need to continue research on the humoral immunity in people with vulnerable immunity in order to select the best tactics for COVID-19 immunization.
Рисунок 3 -Влияние ревматоидного артрита на показатели степени тушения белковой флуоресценции (в %) плазматической мембраны лимфоцитов периферической крови доноров Согласно данным, полученным в ходе исследования, можно предположить, что при системных заболеваниях, в частности, при ревматоидном артрите, происходят изменения структуры и свойств биологических мембран клеток организма. При патологическом состояниии в мембранах лимфоцитов наблюдается нарушение микровязкости липидов на разной глубине липидного бислоя мембран, которое может сопровождаться модификацией структурно-функционального состояния мембранных белков. Данная реакция, по-видимому, имеет неспецифический характер, так как проявляется и при других заболеваниях (например ИБС, атеросклероз и т.д.). Установлено значительное снижение текучести плазматических мембран в зонах белок-липидных контактов, по сравнению с реакцией в липидном бислое. В ряде случаев степень выраженности изменений текучести плазматических мембран клеток крови была взаимосвязана с тяжестью течения заболевания. В отдельных работах было зафиксировано изменение поверхностного заряда плазматических мембран лимфоцитов с положительного на отрицательный, что свидетельствует об гиперполяризации мембран. Микровязкость (текучесть) мембраны сильно влияет на ее функционирование. При увеличении текучести мембрана становиться более проницаемой для воды и других малых гидрофильных молекул, растет скорость латеральной диффузии интегральных белков, что может привести к значительному изменению скорости метаболизма клетки.
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