Abstract
Aim: To evaluate the epidemic situation on measles and rubella and to carry out the laboratory diagnostics of these infections in the North-West of Russia in the period of elimination.Materials and Methods. In 2016-2019 a total of 534 blood serum samples from patients with measles diagnosis, 210 – from patients with rubella diagnosis and 1251 – from patients with exanthema were studied by ELISA using “VectoMeasles-IgM” and “EIA-Rubella-IgM” test-systems.Results. Measles incidence in NWR varied from 0 to 0.96 per 100,000 in 2016 and 2019, respectively. Among measles patients the proportion of children and adults changed in 2018-2019, adults constituted 65.9%. Patients not vaccinated against measles and those with the unknown vaccination status were mainly involved in epidemic process (85%). High level of patients with revaccination status was revealed in 2018 (18.4%). These patients demonstrated high levels of IgG (>3.0 IU/ml) as well as high percentage of IgG avidity (>94.3%) on 4-7th day of rash onset thus evidencing secondary immune response. Molecular studies of the samples from patients revealed the circulation of D8 and B3 genotypes of measles virus. Strains of D8 and B3 genotypes were represented by 3 and 4 variants, respectively. Rubella incidence did not exceed 0.13 per 100,000. Strains of rubella virus of genotype 1E were detected.Conclusion. The data of annual measles incidence and molecular studies of circulating wild type measles viruses prove the on-going measles elimination process in the NorthWest of Russia. For rubella, the persistent phase of elimination was demonstrated in the region.
Highlights
from patients with exanthema were studied by ELISA using
Patients not vaccinated against measles
those with the unknown vaccination status were mainly involved in epidemic process
Summary
Анализ заболеваемости корью и краснухой на 11 территориях Северо-Западного федерального округа (СЗФО) проводили на основании данных формы федерального государственного статистического наблюдения No 2 «Сведения об инфекционных и паразитарных заболеваниях». Лабораторная диагностика кори и краснухи в рамках программы элиминации этих инфекций в Российской Федерации проводится только в вирусологических лабораториях региональных центров по эпидемиологическому надзору за корью и краснухой с помощью тест-систем, рекомендованных ВОЗ [12]. В вирусологическую лабораторию СПбРЦ поступали сыворотки от больных корью, краснухой и экзантемными заболеваниями с 11 территорий. Оценку специфической активности образцов сыворотки по IgG выражали количественно в международных единицах (МЕ/мл) согласно нормативно-технической документации на используемую тест-систему «ВектоКорь IgG» (АО Вектор Бест, Россия). Степень авидности IgGкорь антител определяли с использованием тестсистемы «Avidity:Anti-Measles Virus ELISA/IgG» (Euroimmun, Германия), показатель низкой степени авидности – менее 40%, для высокой степени авидности – более 60%. Материал обрабатывали в соответствии с протоколом (МУ 3.1.2.2356-08) и замораживали при температуре -20°С до получения ответа на наличие антител класса IgM к вирусу кори или IgM к вирусу краснухи. В качес тве порога достоверности отличий было определено значение вероятности p < 0,05
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