В декабре 2019 появилась информация о новом заболевании, этиологическим фактором которого оказался β-коронавирус SARS-CoV-2. В Ленинградской области первый случай COVID-19 выявлен 13 марта 2020 года. Период нарастания интенсивности эпидемического процесса продолжался 8 недель. Через один месяц после достижения максимального уровня заболеваемости было организовано исследование по определению серопревалентности к COVID-19 среди населения Ленинградской области. Работа проводилась в рамках проекта Роспотребнадзора по оценке популяционного иммунитета к вирусу SARS-CoV-2 у населения Российской Федерации с учетом протокола, рекомендованного ВОЗ. Содержание антител к SARS-CoV-2 определяли методом ИФА с использованием набора реагентов для анализа сыворотки или плазмы крови человека на наличие специфических иммуноглобулинов класса G к нуклеокапсиду вируса SARS-CoV-2 производства ФБУН ГНЦПМиБ Роспотребнадзора (г.Оболенск) в соответствии с инструкцией по применению. Результаты исследования показали, что коллективный иммунитет совокупного населения Ленинградской области составил 20,7%. Максимальный уровень коллективного иммунитета установлен у детей 1-6 лет (42,3%) и обследованных старше 70 лет (29,0%). Наибольший уровень серопозитивности, кроме детей и лиц старшего возраста, выявлен у безработных (25,1%). Наименьший уровень серопревалентности установлен в подгруппе госслужащих (12,8%) и подгруппе военных (16,7%). Показано, что при наличии контактов с больными COVID-19 риск инфицирования возрастает в 1,5 раза. После инфекции COVID-19 антитела вырабатываются в 82,1% случаев. У лиц с позитивным результатом ПЦР-анализа, полученным ранее, антитела выявляются в 82,8% случаев. Доля бессимптомных форм среди серопозитивных жителей Ленинградской области составила 86,9%. Результаты оценки популяционного иммунитета к вирусу SARS-CoV-2 у населения Ленинградской области свидетельствуют о том, что в период эпидемического подъема заболеваемости инфекцией COVID-19 сформировался средний уровень серопревалентности. После перенесенного заболевания у 18% лиц, антитела не выявляются. Значительная доля бессимптомных форм инфекции характеризует высокую интенсивность скрыто развивающегося эпидемического процесса. Полученные результаты необходимо учитывать при организации профилактических мероприятий, включая вакцинацию, и прогнозировании заболеваемости.
The first case of COVID-19 was registered in the Leningrad Region on March 13, 2020. The period of increasing intensity of the epidemic process lasted 8 weeks. One month after reaching the maximum incidence rate, a study was organized to determine seroprevalence to COVID-19 among the population of the Region.Objective of the study was to determine the level and structure of community immunity to SARS-CoV-2 virus in the population of the Leningrad Region in the period of intensive COVID-19 transmission.Materials and methods. The work was carried out within the framework of the Rospotrebnadzor project on assessment of community immunity to the SARS-CoV-2 virus in the population of the Russian Federation. The content of antibodies to SARS-CoV-2 was determined applying ELISA using a kit for the analysis of human serum or blood plasma for the presence of specific IgG to the nucleocapsid of the SARS-CoV-2 virus , manufactured by the State Scientific Center of Applied Microbiology and Biotechnology (Obolensk) in accordance with the instructions for use.Results and discussion. The study has showed that the herd immunity of the population of the Leningrad Region was 20.7 %. The maximum level has been established in children 1–6 years old (42.3 %) and people over 70 years old (29.0 %). The highest level of seropositivity, except for children and older people, was found among the unemployed (25.1 %). The lowest level of seroprevalence was detected in civil servants (12.8 %) and military personnel (16.7 %). It has been shown that the risk of infection increases by 1.5 times in case of contacts with COVID-19 patients. After exposure to COVID-19 virus, antibodies are produced in 82.1 % of the cases. In individuals with a positive PCR test result obtained earlier, antibodies are detected in 82.8 % of cases. The share of asymptomatic forms among seropositive residents of the Leningrad Region was 86.9 %. The results of assessing the herd immunity to SARS-CoV-2 in the population of the Leningrad Region indicate that during the period of intensive COVID-19 transmission, an average level of seroprevalence was formed. A significant proportion of asymptomatic forms of infection characterizes the high intensity of the latently developing epidemic process. The results obtained should be taken into account when organizing preventive measures, including vaccination, and predicting morbidity rates.
Background. H. pylori is the principal causative agent of gastroduodenal disorders in humans. The development and severity of lesions in infected individuals depend on the virulence of H. pylori strains. Aims: Detection of virulence determinants and comparative analysis of H. pylori genotypes in patients with chronic gastritis (CG) and duodenal ulcer (DU). Materials and methods. The 53 H. pylori strains were isolated in St. Petersburg from patients with CG (n = 34) and DU (n = 19). The genetic determinants of virulence cagA, iceA, vacA and H. pylori genotypes in patients with CG and UC were determined using the standard PCR method. Results. The cagA gene was found in 64.1% of H. pylori strains. The proportions of cagA+ isolates from patients with CG and DU was 55.8% (15/34) and 78.9% (15/19), respectively (p 0.05). The iceA1 allele of H. pylori was detected in 47.4% of patients with DU, the iceA2 in 47.1% of patients with CG (p 0.05). The vacAs1 allele was significantly dominant in patients with DU 94.7% versus 70.6% in CG (p 0.05). No significant difference in vacA m1 and m2 alleles was found in H. pylori from different groups of patients (p 0.05). All cagA+ strains were carriers of the vacA s1 allele. The vast majority of strains (10 out of 11) of the cagA/vacAs2 genotype were isolated from patients with CG. Conclusion. The significant association between vacAs1, vacAs2 allelic variants, as well as vacA s1/m2, vacA s2/m2 genotypes of the pathogen and severity of clinical manifestations of H. pylori infection has been established in our study. The vacAs1 and vacA s1/m2 genotypes of the pathogen are associated with duodenal ulcer.
(HP) infection was performed using invasive and non-invasive methods. The study group consisted of 95 patients with dyspepsia. HP infection was detected in 47 patients (49.4 %). The expediency of using a set of diagnostic methods for detecting HP (PCR, immunochromatographic, bacteriological and method for determining urease activity) is proved. Most often (100 %) in patients HP infection was detected in biopsies using the PCR method. Somewhat less frequently it was detected when examining biopsies with an invasive biochemical method (AMA RUT Reader) (82 %) and fecal immunochromatographic method (83 %). Despite the fact that helicobacteriosis was detected bacteriologically in a small number of patients (24 %), this method is of particular value, since it allows you to assess the sensitivity to antimicrobial drugs and probiotics, and does not give false positive results.
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