Background. The incidence of hepatitis E (HEV) in Belarus differs from the frequency of occurrence of anamnestic antibodies in the population. Objective. To study the epidemic trends of HEV in Belarus. Material and methods. The study included 5745 samples of blood serum obtained from: residents of Belarus (Brest and Brest region, Minsk and Minsk region) – 2784; foreign citizens - 1457; +ALT and -ALT blood donors – 378; domestic pigs - 1126. All samples were tested for anti-HEV IgG and IgM and 130 samples - for HEV RNA, 9 samples were genotyped by Sanger sequencing. Results. Seroprevalence of anti-HEV IgG in the population amounts to 7.3% (95 CI 5.8-9.0), and in patients with liver damage – to 11.2% (95% CI 9.6-12.9). For foreign citizens it equals 5.22% (95% CI 4.11-6.53), for domestic pigs – 33.75% (95% CI 30.44-37.32). The incidence of anti-HEI IgM in the population amounts to 1.35% (95% CI 0.75-2.22), and in patients with liver damage – to 4.25% (95% CI 3.32-5.37). For foreign citizens it equals 1.03% (95% CI 0.58–1.7), for +AlAT donors – 2.89% (95% CI 1.25–5.69). All HEV RNA sequences isolated in Belarus are caused by genotype 3. Conclusions. Epidemiological characteristics of HEV in Belarus are presented. The anti-HEV immunostructure of various population cohorts was studied. There have been established cases of imported HEV. Autochthonous cases of HEV have been identified as well.
Rationale. Hepatitis E (HE) is a zooanthroponosis. Domestic pigs are the main reservoir for hepatitis E virus (HEV) in the Republic of Belarus (RB). Considering the well-developed pig farming, there is a high risk of infection spread among the population; however, the scale of virus circulation and patterns of HE epidemiology in the above region are still insufficiently explored.The aim of the study is to assess HEV seroprevalence specific for the HE epidemic process in RB.Materials and methods. Serum samples (n = 2,784) collected from patients of infectious disease departments at hospitals (n = 1,669) and relatively healthy people (n = 1,114) from different RB regions were used to measure the activity of alanine aminotransferase (ALT) by a kinetic rate method as well as IgG antibodies to HEV by the enzyme-linked immunosorbent assay (ELISA).Results. In the group of healthy people, anti-HEV IgG were detected in 7.3% (95% CI, 5.8–9.0). In the group of patients with liver disorders, the detection frequency was significantly higher, reaching 11.2% (95% CI, 9.6–12.9). In the groups of healthy people and patients with elevated ALT levels, the HEV seroprevalence did not depend on their gender or the region of residence. The anti-HEV IgG detection frequency gradually increased among olderage patients and reached the peak levels (15.9% on average) in the over-64 age group.Conclusions. RB is characterized by intensive HEV circulation, while the HE epidemic process is characterized by a latent nature. The actual prevalence of HЕ seromarkers among the RB population exceeds the frequency of diagnosed cases, suggesting insufficient vigilance of healthcare workers towards HE and subclinical forms of infection in most of the patients.
Целью настоящего исследования явилось изучение генетического полиморфизма штаммов вирусного гепатита Е (ВГЕ), выделенных из организма человека и животных в Республике Беларусь. Образцы биологического материала от 97 пациентов, 79 свиней, 28 диких кабанов, 40 оленей, 359 кроликов использовали для обнаружения РНК ВГЕ при помощи ПЦР-анализа. Выделенные нуклеотидные последовательности (n=9) подвергли процедуре секвенирования и филогенетическому анализу. Построена модель эволюционных отношений для последовательностей, кодирующих фрагмент белка капсида вируса. Изученные последовательности распределились по двум основным кладам субгенотипов 3-го генотипа вируса. В пределах клады«3abchij» кластеризуется 5 из 9 изученных последовательностей, а в кладе «3efg» – 2 изученных изолята. Последовательности, выделенные из организма кроликов, с вероятностью 94% образуют отдельную кладу дендрограммы в пределах 3-го генотипа. Изученные нуклеотидные последовательности ВГЕ, выделенные из организма человека и животных, кластеризуются с референсными последовательностями 3c, 3f, 3i и 3ra субгенотипов. Доказана возможность завоза ВГЕ в Республику Беларусь с территории Западной Европы и Российской Федерации, а также существование аутохтонных случаев заболевания ВГЕ, имеющих зоонозную природу. The objective of this research was to study the genetic diversity of hepatitis E virus (HEV) strains obtained from humans and animals in Belarus. Samples of biological material from 97 patients, 79 pigs, 28 wild boars, 40 deer, 359 rabbits were tested for HEV RNA in RT-PCR. The obtained nucleotide sequences (n=9) were subjected to sequencing and phylogenetic analysis. A model of evolutionary relationships for the sequences encoding a fragment of the viral capsid protein was constructed. The sequences from this study split up between the two main clades of subgenotypes of the viral genotype 3. Within the “3abchij” clade, 5 of the 9 studied sequences were clustered, and within the “3efg” clade 2 studied isolates were the subject to clustering. The sequences from rabbits formed a separate clade on dendrogram within the genotype 3 with a probability of 94%. The studied HEV nucleotide sequences obtained from humans and animals were clustered with subgenotype reference sequences 3c, 3f, 3i, and 3ra. The possibility of HEV import to the Republic of Belarus from Western Europe and the Russian Federation, as well as existence of autochthonous zoonotic cases of HEV infection have been proved.
Relevance. The frequency of occurrence of anamnestic antibodies to the hepatitis E virus (HEV) in the general population of the Republic of Belarus is 7.3%, which is clearly not consistent with the low incidence of hepatitis E (HE). Most of primary HEV infections remain undiagnosed. The intensive epidemic process of HEV in the Belarusian population is hidden. Conducting epidemiological studies, including genotyping of HEV sequences isolated on the territory of the republic, makes it possible to more accurately characterize the sources of HEV infection and the mechanisms of its transmission. Aim molecular epidemiological study of two cases of acute hepatitis E detected in patients from Belarus. Materials and methods. During 20212022, samples of biological material were obtained from two patients undergoing treatment with an established diagnosis of acute hepatitis E. Serum samples were tested to detect antibodies to HEV using enzyme immunoassay, HEV RNA was detected in fecal samples using nested RT-PCR. The nucleotide sequence was determined by an automatic sequencer using the Sanger method. Analysis of nucleotide sequences, their genotyping, and calculation of evolutionary distances were performed using MEGA X software. Results. The HEV sequence isolated from a pregnant woman who had an epidemiological episode of alimentary contact with raw pork meat is clustered into a common phylogenetic clade with HEV sequence obtained from the patient from Belarus with a history of kidney transplantation and HEV sequences isolated from a domestic pigs. The HEV sequence isolated from a patient with a history of travel to Pakistan belongs to the HEV genotype 1 and joins a clade of HEV sequences isolated in Pakistan, India, Nepal and Mongolia.
Background. The emergence of hepatitis E virus (HEV) in developed countries is driven by improved diagnostic tools, increased clinician awareness of the autochthonous nature of transmission and the potential for life-threatening acute and chronic liver damage. Objective. To present the first confirmed case of acute hepatitis E (AHE) caused by the E virus of the first genotype (HEV-1) in the Grodno region, registered in 2022. Material and methods. The patient is a native of Pakistan, who has been living and working in Grodno for recent years. He visited Italy and Pakistan several times within last six months, returned to Grodno 2 weeks before the onset of clinical manifestations of the disease. The patient was hospitalized in the Regional infectious diseases hospital. The methods for laboratory and etiological diagnosis of hepatitis included: general clinical methods, serological and molecular genetic ones (ELISA - IgM, IgG HEV; PCR - RNA HEV, genotyping and sequencing of the HEV genome). Results. Epidemiological, clinical and laboratory methods made it possible to exclude viral hepatitis A, B, C, D and establish the diagnosis of AHE of icteric (bilirubin at the height of the disease - 209.1 μmol/l, ALT - 1795 U/l), moderate form with a favorable outcome. IgM and IgG to HEV were detected in the patient's blood. HEV RNA was isolated from the patient's biological material. The isolated sequence in 100% bootstrap replications was assigned to HEV genotype 1. The insignificant value of the evolutionary distance between the "Grodno" sequence and the sequence isolated from a patient's body in Pakistan indicated a high degree of their homology, which made it possible to conclude that this case of AHE was imported. Conclusions. For the first time in the Grodno region, there was registered an imported case of AHE acquired during travel to HEV hyperendemic territory. The identified sequence is 100% HEV-1 genotype and 94.3% homologous to the sequence obtained from a patient in Pakistan. Under favourable conditions, HEV-1, which has a significant epidemic potential, can cause the development of HEV outbreaks.
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