Detection of antibodies to the hepatitis E virus in domestic reindeer (Rangifer tarandus) in the Republic of Sakha (Yakutia)

INTRODUCTION

Although domestic pigs and wild boars are the main reservoir of zoonotic hepatitis E virus (HEV) genotypes in temperate countries, the presence of antibodies to HEV (anti-HEV) in the indigenous population of circumpolar territories, i.e. outside the habitat of wild and domestic pigs, indicates the presence of an alternative reservoir of the virus. Reindeer (Rangifer tarandus) may be a potential reservoir for HEV in the polar regions. The purpose of the study was to determine the prevalence of anti-HEV among domestic reindeer in the Republic of Sakha (Yakutia).

MATERIALS AND METHODS

Sera from 497 domestic reindeer from the Oymyakon (n = 425) and Ust-Yansky districts (n = 72) of the Republic of Sakha (Yakutia) were tested for anti-HEV. A commercial ELISA kit DS-ELISA-ANTI-HEV-G (Diagnostic Systems-Stolitsa LLC, Russia) was used for detection of anti-HEV IgG, but a rabbit polyclonal antibody against deer IgG labeled with horseradish peroxidase (KPL, USA) at a dilution of 1 : 100 in phosphate-buffered saline were used instead of the human specific conjugate from the kit.

RESULTS

The average detection rate of anti-HEV in reindeer sera was 15.5% (95% CI: 12.6-19.0%). The detection rate of anti-HEV significantly increased with age, from 3.5% (95% CI: 1.1-9.0%) in calves aged 3-6 months to 25.0% (95% CI: 1.6 -36.5%) in deer aged 2-4 years (p < 0.0001). From this age group, anti-HEV detection rates reached a plateau, not differing significantly between older age groups (p > 0.05). The average anti-HEV detection rate among reindeer 2 years of age and older was 19.0% (95% CI: 15.3-23.4%). There were no statistically significant differences in the frequency of anti-HEV detection between female and male reindeer, both among adult animals and among calves.

CONCLUSION

The observed anti-HEV detection rates among domestic reindeer in the Republic of Sakha (Yakutia) indicate that infection caused by HEV or an antigenically similar virus is common in these animals. The dynamics of antibody accumulation in the reindeer population indicates that infection apparently occurs during the first two years of life.

Markers of antroponotic viral infections in vervet monkeys arrived from their natural habitat (Tanzania)

INTRODUCTION

Various human viruses have been identified in wild monkeys and in captive primates. Cases of transmission of viruses from wild monkeys to humans and vice versa are known. The aim of this study was to identify markers of anthroponotic viral infections in vervet monkeys (Chlorocebus pygerythrus) arrived from their natural habitat (Tanzania).

MATERIALS AND METHODS

Fecal samples (n = 56) and blood serum samples (n = 75) obtained from 75 animals, respectively, on days 10 and 23 after admission to the primate center, were tested for the markers of anthroponotic viral infections (Ebola virus, Marburg virus, lymphocytic choriomeningitis, hepatitis C virus, herpes simplex virus (HSV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), parainfluenza types 1 and 3, intestinal adenoviruses, rotaviruses) by enzyme immunoassay (ELISA) and polymerase chain reaction (PCR).

RESULTS AND DISCUSSION

Among the examined animals, markers of 6 out of 11 tested viral infections were identified. Detection rates of IgG antibodies to HSV-1,2 (15.9%) and CMV (15.9%) were two times as low as IgG antibodies to EBV (31.8%). Among the markers of respiratory viral infections, IgG antibodies to parainfluenza virus type 1 were found (6.8%). 14.3% of the animals had rotavirus antigen, and 94% had simian adenovirus DNA. Markers of hemorrhagic fevers Ebola, Marburg, LCM, hepatitis C, and type 3 parainfluenza were not detected.

CONCLUSION

When importing monkeys from different regions of the world, an expanded screening for viral infections is needed considering the epidemiological situation both in the country of importation and in the country of destination.

[Enteral viral hepatitis in monkeys]

Within the last decade, a large number of viruses genetically related to human hepatitis viruses have been identified in different animal species, including monkeys. Numerous viruses related to human hepatitis A virus (HAV, Picornaviridae: Hepatovirus: Hepatovirus A) were detected in various mammalian species in 2015-2018, predominantly in bats and rodents, but also in shrews, seals and marsupials. Zoonotic hepatitis E virus (HEV, Hepeviridae: Orthohepevirus: Orthohepevirus A) genotypes have been found in wild boars, deer, camels, and rabbits, as well as in non human primates. In addition, viruses that are genetically close to HEV have been described in bats, ferrets, rodents, birds, and fish. Nevertheless, monkeys remain important laboratory animals in HAV and HEV research. The study of spontaneous and experimental infection in these animals is an invaluable source of information about the biology and pathogenesis of these viruses and continues to be an indispensable tool for vaccine and drug testing. The purpose of this literature review was to summarize and analyze published data on the circulation of HAV and HEV among wild and captive primates, as well as the results of experimental studies of HAV and HEV infections in monkeys.

[Prevalence of laboratory markers of human respiratory viruses in monkeys of Adler primate center]

INTRODUCTION

The relevance of studying the circulation of human respiratory viruses among laboratory primates is associated with the need to test vaccines and antiviral drugs against these infections on monkeys.The aim of this work was to study the prevalence of serological and molecular markers of human respiratory viral infections in laboratory primates born at the Adler Primate Center and in imported monkeys.

MATERIAL AND METHODS

Blood serum samples (n = 1971) and lung autopsy material (n = 26) were obtained from different monkey species. These samples were tested for the presence of serological markers of measles, parainfluenza (PI) types 1, 2, 3, influenza A and B, respiratory syncytial (RS) and adenovirus infections using enzyme immunoassay (ELISA). Detection of RS virus, metapneumovirus, PI virus types 1-4, rhinovirus, coronavirus, and adenoviruses B, C, E and bocavirus nucleic acids in this material was performed by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS AND DISCUSSION

The overall prevalence of antibodies (Abs) among all monkeys was low and amounted 11.3% (95% CI: 9.2-13.7%, n = 811) for measles virus, 8.9% (95% CI: 6.2-12.2%, n = 381) for PI type 3 virus, 2.5% (95% CI: 0.8-5.6%, n = 204) for PI type 1 virus, and 7.7% (95% CI: 3.8-13.7%, n = 130) for adenoviruses. When testing 26 autopsy lung samples from monkeys of different species that died from pneumonia, 2 samples from Anubis baboons (Papio аnubis) were positive for of parainfluenza virus type 3 RNA.

CONCLUSION

Our data suggest the importance of the strict adherence to the terms of quarantine and mandatory testing of monkey sera for the presence of IgM antibodies to the measles virus that indicate the recent infection. The role of PI virus type 3 in the pathology of the respiratory tract in Anubis baboons has been established.

[Animal delta-like viruses (Kolmioviridae: Deltavirus) and the origin of the human hepatitis D virus (HDV)]

Hepatitis D (delta, δ) virus (HDV) was discovered more than 40 years ago, but the understanding of its origin and evolution is poor. This is mainly due to the lack, until recently, of data on the existence of any viruses similar to HDV. The discovery in recent years of sequences of new delta-like agents in a wide range of vertebrate (Vertebrata) and invertebrate (Invertebrata) species has facilitated a revision of views on the origin of HDV and contributed to understanding the place of this unique virus among other animals' viral agents. The purpose of this review is to analyze the latest published data on new delta-like agents and their biological characteristics.

[Markers of viral hepatitis E (Hepeviridae, Orthohepevirus, Orthohepevirus A) in the imported Old World monkeys]

INTRODUCTION

Viral hepatitis E is a zooanthroponotic disease that occurs in humans and various animals, including monkeys. It is caused by hepatitis E virus (HEV) (Hepeviridae, Orthohepevirus: Orthohepevirus A), for which 8 genotypes have been described to date. Among them, strains of genotypes 1 and 2 have been isolated from humans, strains of genotypes 3 and 4 from humans and animals, and strains of genotypes 5-8 from animals only. The main threat of the disease is associated with the documented zoonotic transmission of HEV genotypes 3, 4, 7, and 8, to humans through infected meat, blood and milk. Thus, monkeys could be involved in the transmission of HEV.The aim of this work was to study serological and molecular genetic markers of HEV infection in strepsirrhines (Old World monkeys, Cercopithecoidea), imported to the Adler Primate Center from various regions of the world (Tanzania, Vietnam, Mauritius).

MATERIAL AND METHODS

Fecal (n = 224) and blood serum samples (n = 395) from cynomolgus (Macaca fascicularis) and vervet monkeys (Chlorocebus pygerythrus) were examined by the enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR).

RESULTS AND DISCUSSION

The data obtained show the high detection rate (51.8%) of IgG antibodies to HEV among 5 groups of cynomolgus monkeys imported from Vietnam, with a predominance of highly reactive sera (84%). High detection rate of IgM antibodies in these animals (10.4%) was observed, with the large number of IgM-reactive sera in one particular group of animals (36.8%). The fact of detection of HEV RNA in two groups of cynomolgus monkeys (11.9% and 5.7%) is of particular importance. All HEV sequences of isolated from monkeys belonged to genotype 4.

CONCLUSION

Our data indicate that monkeys (in particular, cynomolgus monkeys) can serve as a natural reservoir of HEV genotype 4 for humans. This requires an appropriate set of anti-epidemic measures in a number of situations.

Contemporary strategy to control viral hepatitis A in the Russian Federation

The problem of choosing a strategy to control hepatitis A in the Russian Federation remains relevant for the health care of our country. By strategy we mean a scientifically based program of action that defines the priorities and resources needed to effectively control hepatitis A.

The aim of the work is to present a strategy to control hepatitis A in the Russian Federation, taking into account the realities of today. Based on the analysis of Russian and international studies, we present answers to the questions that should be addressed before the choosing a strategy to control hepatitis A in the Russian Federation. The low incidence of hepatitis A creates a false image of the favorable situation with this infection. The rationale is given to include vaccination against hepatitis A in the National Vaccination Schedule in the section of mandatory vaccinations. Routine vaccination of children aged 24 and 36 months will lay the foundation for future protection against this infection. We consider the creating a National Hepatitis A Vaccination Program as an important aim. The implementation of such a program will allow full control of hepatitis A in the Russian Federation.

[Clinical course and outcomes of chronic viral hepatitis D in patients from Republic of Tuva as endemic region]

INTRODUCTION

Hepatitis D (delta, 5) is caused by an RNA virus (hepatitis D virus, HDV) from genus Deltavirus, and is the most severe and difficult to treat disease among both viral hepatitis and infectious diseases in general. The development of HDV infection in the host organism is possible only in the presence of hepatitis B virus (HBV). Coinfection with HBV and HDV is associated with a more rapid progression of chronic viral hepatitis (CVH) to liver cirrhosis (LC) and an unfavorable outcome in comparison with HBV monoinfection. Data on the influence of clinical, biochemical and virological factors on the infectious process in patients with hepatitis D are limited due to the insufficient amount of research on this theme.The study aimed to determine demographic, clinical, biochemical, and virological factors influencing the course and progression of CVH D in patients followed during 10 years, residing in the territory of the Tuva Republic, one of the endemic regions of the Russian Federation.

MATERIAL AND METHODS

Changes in clinical and laboratory parameters were analyzed in dynamics in 121 HDV infected patients with a different course of the disease, who were under observation from 2009 to 2019. Three groups of patients were identified: group 1 - 61 patients with disease progression of chronic hepatitis to LC (Child-Pugh class B-C), group 2 - 49 patients with non-progressive chronic hepatitis, and group 3 - 11 patients with slowly progressive LC (class A). Demographic data, the presence of detectable HBV DNA, indicators of the functional state of the liver: alanine aminotransferase (ALT/GPT), aspartate aminotransferase (AST/GOT), alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), and total bilirubin content were analyzed. The severity of hepatic encephalopathy was assessed by the duration of the numbers connection test (NCT).

RESULTS

All patients belonged to the same ethnic group (Tuvinians), were infected with HDV genotype 1 and were positive for HDV RNA throughout the entire follow-up period. There were no significant differences in sex ratio and mean age at the time of inclusion in the study between the groups. In group 1, the average number of years from inclusion in the study to the formation of LC was 3.65 ± 2.3 years, years to the lethal outcome: 4.5 ± 3 years. Significantly higher levels of AST/GOT, ALP, GGT, total bilirubin (TB) and NCT grade were found in group 1 compared to group 2. ALT/GPT levels did not differ significantly in these groups. When comparing groups with disease progression and slowly progressive LC (groups 1 and 3), no significant differences were found in any of the clinical and biochemical parameters. ALT/GPT, GGT, TB and NCT values were significantly higher in patients with slowly progressive LC (group 3) compared to group 2. No differences in AST/GOT and ALP levels were found between these groups. Detectable HBV DNA was significantly more frequent in patients with progressive disease and with chronic viral hepatitis than in patients with slowly progressive LC. There were no significant differences in the frequency of HBV DNA detection in patients from groups 1 and 2.

CONCLUSION

The results obtained on a relatively homogeneous cohort demonstrated that age and gender are not the factors influencing the progression of chronic viral hepatitis D to cirrhosis. The lack of detectable HBV DNA is associated with the slow progression of LC. The revealed differences in clinical and biochemical parameters reflect the degree of functional liver damage in chronic viral hepatitis D and HDV-associated cirrhosis.

[Seroprevalence of hepatitis E virus (Hepeviridae: Orthohepevirus: Orthohepevirus A) among pregnant women in the highly endemic region of Kyrgyzstan]

INTRODUCTION

Hepatitis E (HE) is an important public health problem worldwide and is especially significant for pregnant women, among whom the associated mortality rate reaches 25%. The distribution of HE serological markers in this cohort in the endemic regions of Central Asia is poorly understood. The aim of the study was to assess the seroprevalence of HEV among pregnant women in the region of Kyrgyzstan where an increased incidence of HE is reported.

MATERIAL AND METHODS

Blood serum of pregnant women, obtained from medical institutions in Bishkek, city of Osh and Osh region in the period from September 2016 to October 2019, and the control group of clinically healthy women were tested using the test systems "DS-IFA-ANTI-HEV-G" and "DS-IFA-ANTI-HEV-M" (NPO "Diagnostic Systems", Russia).

RESULTS

IgG antibodies to HEV were detected in 87 (5.9%) of 1472 examined pregnant women, IgM antibodies -in 64 (4.8%) of 1378, while 5 (0.34%) samples were simultaneously positive for IgG and IgM antibodies. The rates of detection of antibodies to HEV in women of three age categories from 17 to 36 years old in the studied and control groups were similar. The analysis of the seasonal dynamics of HEV seroprevalence in pregnant women in the period from February to September 2019 showed a tendency towards an increase in the values of the positivity coefficient of specific IgM antibodies by the beginning of the autumn. Antibodies to HEV were detected with highest frequency in women from Osh region.

CONCLUSIONS

A high risk of HEV infection for pregnant women in the surveyed region had been shown.

[The risk groups of infection with hepatitis С virus in conditionally healthy population of the Belgorod oblast]

The purpose of study was to establish risk group on hepatitis C in conditionally healthy population of the Belgorod oblast. Total 2025 conditionally healthy inhabitants aged between 1 and 99 were surveyed and serum samples from them were tested. There were eight age groups: 1-14 years (12.3%), 15-19 years (13.1%), 20-29 years (12.7%), 30-39 years (12.8%), 40-49 years (12.8%), 50-59 years (11.8%), 60-69 years (8.6%) and over 70 years of age (15.7%). Overall, 44.6% of the examined persons were male. 41.3% (ranging from 6.5 to 72.1%) of respondents reported surgery in their anamnesis, 5.1% (ranging from 0.8 to 12.6%) had blood/blood products transfusion, 10.3% (ranging from 1.7 to 57.9%) ear/nose piercing and 2.96% (ranging from 0.8 to 6.6%) tattoos. There were no people who injected drugs. The piercing was significantly higher in age groups 15-19 years and 20-29 years than other age groups (p-value<0.05). The tattoos were significantly higher in group of 70 years and older than in age groups 15-19 years, 30-39 years and 40-49 years (p-value<0.05). Anti-HCV antibodies were detected using third-generation enzyme-linked immunosorbent assay ("IFA-ANTI-HCV", Nizhny Novgorod). The HCV RNA was tested with RT-PCR. The Anti-HCV was detected in 22 persons (1.1%), 77.3% out of them were older than 53 year and they were born prior to 1965. The Anti-HCV were significantly higher for the people over 70 years of age than in the age groups of 1-14 years, 15-19 years, 30-39 years and 40-49 years (p-value<0.05). The 2.65% of the examined persons were older 53 years had anti-HCV. Only 0.36% of anti-HCV were found in the young age groups of the examined persons who were born after 1965, the percentage was significantly lower than in older age groups (p-value<0.05). The 16 people had RNA-HCV and 87.5% persons were born in or before 1965. There was one person with genotype 3a (age group 30-39 years), 15 persons with genotype 1b (fourteen out of them were older 53 years and one person was in the age group 20-29 years. The study established that risk age group are inhabitants born before 1965 in Belgorod region. It can be taken into account in regional hepatitis С screening programs.

[The estimation of the hepatitis E proportion in the etiological structure of acute viral hepatitis in certain regions of of Kyrgyzstan.]

Despite the fact that the Kyrgyz Republic (KR) belongs to the highly endemic regions of the world for hepatitis E, the true extent of the spread of this infection in the country remains poorly understood. It was estimated the prevalence of serological markers of hepatitis E virus (HEV) infection among patients with acute viral hepatitis (AVH) from the regions of the Kyrgyz Republic with a high level of seroprevalence previously established by us. Blood sera samples of hepatitis patients who were admitted to hospitals of Kyrgyzstan in the period 2018-2019 were examined by the enzyme immunoassay method using the kits «DS-ELISA-Anti-HEVIgG» and «DS-ELISA-ANTI-HEV-IgM» (RPC Diagnostic Systems, Russia). IgG and IgM antibodies to HEV were detected in 103 of 344 studied samples (29.9%). Most often, seropositive specimens were detected among people of age groups under 20 and over 40 years old. Hepatitis with the fecal-oral mode of transmission was dominated in the structure of AVH: the specific gravity of hepatitis E was 47.9%, hepatitis A - 35.32%. Markers of mixed infections with other hepatitis viruses have been detected in 40.4% IgM-positive individuals. Thus, high prevalence of serological markers of HEV infection in the territory of Kyrgyzstan during the interepidemic period had been shown. The necessity of including the determination of serological markers of hepatitis E into the algorithm for the comprehensive diagnosis of AVH in patients of all age groups with liver pathology had been confirmed.

[The system of epidemiological control of hepatitis E and complex of anti-epidemic, hygienic and veterinary sanitary activities in the Belgorod oblast]

The Hepatitis E (HE) is a viral liver disease that is common on all continents at different rates and very frequently is not symptomatically distinguishable from other viral hepatitis, such as hepatitis A, B and C, as well as from other infectious diseases referred to as "acute jaundice syndrome". The GE-anthroponosis (in the case of infection caused by genotypes 1 or 2 of hepatitis E virus) or anthropozoonosis (in the case of infection caused by 3 or 4 viruses) is predominantly propagated through fecal-oral transmission. The article presents the general characteristics of VGE, human risk factors and means of prevention. The particular attention is paid to the development of complex of anti-epidemic, hygienic and veterinary sanitary measures in the Belgorod Oblast.

DEVELOPMENT OF HEPATITIS E 3 GENOTYPE RECOMBINANT PROTEIN CAPSID OF: CLONING, EXPRESSION, PURIFICATION, EVALUATION OF THE ANTIGENIC PROPERTIES

Aim. The development of the hepatitis E virus (HEV) genotype 3 recombinant capsid protein.Materials and methods. E.coli strains, plasmid vectors, serological and clinical samples, ELISA reagent kits, molecular biological, bioinformatic, biotechnological, biochemical and serological methods.Results. Using viruscontaining material from pigs of Belgorod region (Russian Federation) we made E.coli strains producing recombinant capsid protein, containing C-terminal of viral ORF2 protein fragment fused to E.coli β-galactosidase. Recombinant protein ORF2 had been isolated from the bacterial inclusion bodies and purified by size exclusion chromatography. Antigenic specificity of the recombinant polypeptide was confirmed by ELISA and Western blotting with sera of hepatitis E patients and reference groups (healthy donors, patients with hepatitis A, B, C, infectious mononucleosis, cytomegalovirus infection and HIV-infected patients). Conclusion. HEV genotype 3 ORF2 recombinant antigen had been developed, and the possibility to use it in diagnostic tests had been experimentally shown.

[The duration of preservation of anamnestic antibodies to hepatitis E virus.]

The purpose of the study was to determine the duration of antibody response against hepatitis E virus (anti-HEV). Veterans of the war in Afghanistan who were in this endemic region in the late 1970s and early 1980s were tested for anti-HEV. On average, 20 years after the end of military service in Afghanistan, the rate of seropositivity was 30.0% (95/317), which was significantly higher compared to positivity rates in males who were at military service in the territory of Russia during the same period (3.9%, 8/208). At an average of 29.5 years after the visit to Afghanistan anti-HEV prevalence in veterans dropped to 20.0% (21/105), but still significantly exceeded the seroprevalence in general population (3.8%). Serum samples from elderly individuals (>60 years) without known risk factors of infection were also tested for anti-HEV IgG and IgM (n = 896). Anti-HEV IgG detection rates in the elderly from two regions of Russia exceeded those observed of primary blood donors (18.0-27.8% vs. 4.5-10.0%, p<0.01). The detection of anti-HEV IgM in individuals above 60 years (2.7-6.9%) indicates a current or recent infection. Thus, anti-HEV IgG can persist several decades after the infection. This might account for the wide anti-HEV prevalence among the elderly. At the same time, a significant proportion of individuals exposed to HEV lose detectable anti-HEV IgG within 20-30 years. The detection of anti-HEV IgM among the elderly indicates the viral circulation in older age groups, suggesting the need for testing for hepatitis E markers in elderly patients with liver diseases.

[Markers of hepatitis A in the monkeys of the Adlers primate center.]

Hepatitis A is a widespread viral infection. The HAV strains of "human" and "monkey" origin are similar in their morphological and antigenic properties, but differ genotypically.

OBJECTIVES

The aim of this research was a comparative study of serological and molecular-genetic markers of HAV infection in monkeys born at the Adler Primate Center and in those imported from different countries.

MATERIAL AND METHODS

Fecal samples (n = 313) and serum (n = 266) from various species of monkey using ELISA and RT-PCR were studied.

RESULTS AND DISCUSSION

The frequency of anti-HAV-IgG was high (78.9%) in imported animals (vervet monkeys from Tanzania and cynomolgus monkeys from Vietnam) and as well as in various species of monkeys (rhesus monkeys, cynomolgus monkeys, green monkeys and papio hamadryas) of the Center (88.6%). At the same time, in the imported monkeys, the markers of "fresh" HAV infection (IgM-27.2%, Ag-HAV-16.7%, RNA-22.0%) were detected significantly more often (p> 0.05) than in monkeys kept at the Colony (IgM-7.5%, HAV-Ag - 5.2%, RNA - 3.6%). In general, anti-IgG reactivity ranged from 1.064 to 2.073 OD₄₅₀, anti-IgM ranged from 0.546 to 1.059 OD₄₅₀. The number of HAV-Ag was 0.496 - 1.995 OD₄₅₀. RNA HAV only in rhesus monkeys and cynomolgys monkeys born at the Colony, as well as in imported vervet monkeys was detected.

CONCLUSIONS

The data obtained indicate a wide circulation of HAV among monkeys born in the Adler Primate Center and among the imported animals. Markers of "fresh" HAV infection varied depending on the species of monkeys and their origin.

[Belgorod region - the territory endemic for hepatitis E.]

INTRODUCTION

Belgorod region is the territory with the highest incidence of hepatitis E in the Russian Federation.

OBJECTIVES

The aim of the study was to comprehensively characterize the circulation of hepatitis E virus (HEV) in the Belgorod region, including the study of population immunity to the virus, determining the prevalence of infection among the pig population and analysis of the genetic diversity of HEV from patients and animals.

MATERIAL AND METHODS

Serum samples of a conditionally healthy population (n = 2027) of all age groups were tested for anti-HEV IgG and IgM by ELISA with commercial assays. HEV RNA was determined in fecal samples from pigs aged 2-4 months (n = 526), in sewage samples from pig farms (n = 10), as well as in stool samples from patients with hepatitis E (n = 6) using reverse transcription polymerase chain reaction (RT-PCR). Phylogenetic analysis was performed for an amplified 300 nt fragment corresponding to HEV open reading frame 2.

RESULTS AND DISCUSSION

The prevalence of anti-HEV IgG in general population averaged 16.4% (95% CI: 14.8-18.1; 332/2027). The proportion of individuals who had both anti-HEV IgM and IgG averaged 2.8% (95% CI: 2.2-3.6; 57/2027). The incidence rate of anti-HEV IgG increased with age, from 2.8% (95% CI: 1.3-5.8) in children aged 1-14 years to 40.1% (95% CI: 34.9-45.6) in people 70 years or older. The detection rate of HEV RNA in pigs was 20% (95% CI: 16.8-23.6; 105/526). HEV RNA was detected in 2 out of 10 sewage samples. The HEV sequences isolated from patients with hepatitis E, pigs, and sewage samples in Belgorod region belonged to the HEV genotype 3, had a 95-100% homology, and formed common clusters on a phylogenetic tree.

CONCLUSIONS

The high prevalence of HEV in pigs population has led to the formation of an endemic territory in the Belgorod region, which is the center of pig breeding. Measures aimed at reducing the circulation of HEV among pig population and decontamination of sewage from pig farms are necessary to control HEV infection.

OBTAINING THE RECOMBINANT ORF3 PROTEIN OF HEPATITIS E GENOTYPE 3 AND EVALUATION OF ITS ANTIGENIC PROPERTIES

Aim. Design аис1 construction of the hepatitis E virus (HEV) genotype 3 full-size ORF3 recombimnt polypeptide. Materials and methods. Escherichia coli strains, ptasmid vectors, serologiral and biological amples, molecular biological, bioinformatic, biotechnological, biochemical and serological methods.Results. RNA was isolated from pig fecal extracts collected on Belgorod farms and was used in RT-PCR to obtain the fragment of the orf3 gene of the hepatitis E virus genotype 3. Using A/T-cloning a recombinant plasmid was obtained with insertion of a DNA fragment (230 bp) encoding the N-terminal region of the ORF3 protein. The primary structure of the missing C-terminal region of the ORF3 VGE of the genotype 3 was calculated by bioinformatics methods. Codon optimization of the sequence for biosynthesis in E.coli cells was performed. For constructing the recombinant plasmid a chemically synthesized DNA fragment encoding the fulllength ORF3 protein had been used. E.coli strain producing full-size recombinant protein ORF3 fused to E.coli beta-galactosidase was developed. Recombinant protein ORF3 had been isolated from the inclusion bodies of the E.coli biomass and purified by size exclusion chromatography. Antigenic specificity of recombinant polypeptide had been confirmed in immunochemical reactions (ELISA, Western blot) with sera from patients with hepatitis E and control groups of patients. Conclusion. HEV genotype 3 ORF3 recombinant antigen had been designed, and itfs applicability in diagnostic tests had been experimentally confirmed.

DESIGN OF HEPATITIS E VIRUS GENOTYPE 1 RECOMBINANT ORF3 PROTEIN BY CODON OPTIMIZATION METHOD

Aim. The development of the hepatitis E virus (HEV) genotype 1 full-size ORF3 recombinant polypeptide. Materials and methods. Escherichia coli strains, plasmid vectors, serological and clinical samples, ELISA reagent kits, molecular biological, bioinformatic, biotechnological, biochemical and serological methods. Results. HEV genotype 1 RNA had been isolated from clinical samples collected in Kyrgyzstan. DNA copy of subgenomic virus RNA had been cloned and used for further development of E.coli strains producing full-size recombinant protein ORF3 fused to E.coli beta-galactosidase. Codons optimization method was used in aim to increase expression level of recombinant protein. Recombinant protein ORF3 had been isolated from the inclusion bodies of the E.coli biomass and purified by size exclusion chromatography. Antigenic specificity of recombinant polypeptide had been confirmed by enzyme-linked immunosorbent assay and Western blotting with the specific sera. Conclusion. HEVgenotype 1 ORF3 recombinant antigen had been designed, and it’s applicability in diagnostic tests had been experimentally confirmed.

DESIGN OF HEPATITIS E VIRUS GENOTYPE 1 RECOMBINANT CAPSID PROTEIN: CLONING, EXPRESSION, PURIFICATION, EVALUATION OF THE ANTIGENIC PROPERTIES

Aim. The development of the hepatitis E virus (HEV) genotype 1 recombinant capsid protein. Materials and methods. Escherichia coli strains, plasmid vectors, serological and clinical samples, ELISA reagent kits, molecular biological, bioinformatic, biotechnological, biochemical and serological methods. Results. Using HEV genotype 1 DNA copy of subgenomic virus RNA we made E.coli strains producing recombinabt capsid protein, containing C-terminal fragment of ORF2 protein fused to E.coli beta-galactosidase. Recombinant protein ORF2 had been isolated from the inclusion bodies of the E.coli biomass and purified by size exclusion chromatography. By Western blotting it had been shown specific interaction of the recombinant polypeptide with anti-HEV IgG from pool of positive sera. Antigenic specificity of the recombinant polypeptide had been confirmed by enzyme-linked immunosorbent assay with sera of hepatitis E patients and reference groups: healthy donors, patients with hepatitis А, В, C, infectious mononucleosis and cytomegalovirus infection, HIV-infected patients. Conclusion. HEV genotype 1 ORF2 recombinant antigen had been developed, and its possible use in diagnostic tests had been experimentally shown.

MODELLING OF HEPATITIS E IN MINI-PIGS

Aim. Experimental reproduction of HEV-infection in mini-pigs and comparative analysis of virological and immunological characteristics of experimental infection. Materials and methods. Wiesenauer minipigs (2 females and 4 males, age 50 - 60 days, weight 5-10 kg) were infected by HEV genotype 3 strain isolated from swine feces in Belgorod region in 2013. The virus was administered as a 10% clarified feces extract (800 pi). Blood (weekly) and feces (daily) were sampled from the animals for 49 days. Anti-HEV IgG were determined in sera samples using DS- ElA-ANTI-HEV-G (Diagnostic Systems) system, HEV RNA in samples of feces extracts and blood sera - RT-PCR. Results. Wiesenauer minipigs were sensitive to HEV genotype 3 infection, infection developed in all the animals after administration of the virus, that was accompanied by the presence of HEV RNA in feces for 2 weeks and seroconversion by anti-HEV. Comparative analysis of virological characteristics of experimental H EV-infection in mini- and standard pigs has shown, that the duration of the infection in mini-pigs is shorter, and seroconversion by anti-HEV occurs earlier. Conclusion. Sensitivity to HEV genotype 3 and lower weight make mini-pigs a comfortable alternative to standard swine and primates for modelling HEV infection in vivo.

Markers of hepatitis E among the population of the Greater Sochi and in monkeys of the Adler primate center

Serum from humans (n = 646) and monkeys (n = 1867) collected during the period 1999-2013 was tested by enzyme immunoassay. Anti-HEV IgG was detected significantly more frequently (P ≥ 0.001) in rhesus macaques (Macaca mulatta) - 45.1 ± 1.6% (n = 1001) than in cynomolgus macaques (M. fascicularis) 16.2 ± 1.8% (n = 426). Single seropositive individuals were found among M. nemestrina - 4.0±2.8% (n = 50). Anti-HEV was not detected in the sera of green monkeys (Chlorocebus aethiops) - n = 162, Papio hamadryas (n = 124), and Papio anubis - n = 104. The presence of the anti-HEV IgM indicating the cases of fresh infection in Macaca mulatta - 2.1 ± 0.5% (n = 717) and M. fascicularis - 3.5 ± 1.3% (n = 266) is of great significance. The overall frequency of detection of the anti-HEV IgG among the staff of the Adler Primate Center - 6.8 ± 2.3% (n = 118) was significantly lower (P ≤ 0.001) than among the population of the Greater Sochi - 15.9% ± 1.6 (n = 528). It is important that only in patients of medical institutions (clinic, hospital, cancer center), anti-HEV IgM were detected (2.7-11.8%) along with anti-HEV IgG (15-23.5%), thereby indicating the presence of acute cases of HEV infection among this population. HEV RNA was not detected in the serum of anti-HEV IgM-positive people and monkeys. Seroepidemiological data do not confirm the assumption on the ability of seropositive monkeys of Macaca genus to be a natural reservoir of HEV infection for humans.

A CASE OF IMPORT OF GENOTYPE 4 HEPATITIS E VIRUS INTO RUSSIA

Aim. Description of the first documented case of imported hepatitis E, associated with genotype 4 of HEV and introduced from southern France. Materials and methods. Clinical, epidemiologic and laboratory analysis of the imported case of disease of hepatitis E was carried out. Phylogenetic analysis of nucleotide sequences of HEV isolate, taken from the patient, was carried out. Results. Epidemiologic analysis allowed to assume imported character of the detected case of HEV-infection. Comparative analysis of nucleotide sequences of regions of the open reading frame 2 (300 nt) and open reading frame 1 (721 nt) of HEV genome, isolated from the patient, showed identity of this isolate with variants of genotype 4 HEV, isolated in France in 2009 - 2011 from patients with autochthonous hepatitis E. Conclusion. The results obtained confirm the case of import into Russia of genotype 4 HEV from south-eastern France (Corsica), where spread of this virus genotype is observed in recent years.

Simulation of Viral Hepatitis E in Marmosets

We developed a model of hepatitis E virus infection in common marmosets (Callithrix jacchus) and determined optimal route of infection, duration, clinical and virological characteristics of infection in laboratory animals. Using this model, we demonstrated that replication of hepatitis E virus primarily occurs in the liver, while virus replication presumed to take place in the intestine was not confirmed in this experiment.

[The standardization of diagnostic of hepatitis E.]

The study was carried out to develop approaches to standardization of laboratory diagnostic of hepatitis E. The three stages of standardization are establishment of analytical sensitivity of molecular test for detection of RNA of virus of hepatitis E; establishment of analytical sensitivity in International Units of enzyme-linked immunosorbent assay testing widely applied in Russia for detection of anti-virus of hepatitis E; And development of national reference material - standard anti-virus of hepatitis E IgG validated relatively to International standard. The results of study permitted to develop tools for standardizing of laboratory diagnostic of hepatitis E and epidemiological control of the given function - molecular test for detecting RNA of virus of hepatitis E with sensitivity within range of 1250250 IU/ml, data concerning analytical sensitivity of commercial enzyme-linked immunosorbent assay testing for detecting anti-virus of hepatitis E (0.25 IU/ml) and national standard of anti-virus of hepatitis E with concentration of 5 IU/ml.

[Prevalence of hepatitis E markers in children]

AIM

Frequency of detection determination for past and current hepatitis E virus (HEV) infection markers in children with immune suppression, as well as children with normal immune status.

MATERIALS AND METHODS

The presence of HEV markers (anti-HEV IgG and IgM, HEV RNA) was studied in 609 sera samples of children with neurologic pathologies, 87 samples--from children with immune deficiencies, as well as 3122 samples from conditionally healthy children of 6 regions of Russia. The children were divided into 5 age groups. Anti-HEV IgG and IgM determination was carried out in EIA, HEV RNA--by RT-PCR.

RESULTS

The frequency of detection of anamnestic anti-HEV IgG turned out to be significantly higher among immune-compromised. children compared with healthy children (5.7% against 1.4%, p < 0.05). Anti-HEV IgM, that testify to current or recent infection, were also detected significantly more frequently among children with immune-suppression (1.1-1.6%) compared with healthy children (0.25%, p < 0.05). HEV RNA was detected in 1 child with the absence of anti-HEV IgM and IgG. Nucleotide sequence analysis of HEV confirmed membership of this isolate in genotype 3, that is prevalent in non-endemic territories.

CONCLUSION

The data obtained have demonstrated, that HEV-infection is prevalent among children in Russia and its course is, probably, asymptomatic in most cases. Immune suppression is a factor of increased risk of infection of children with HEV.

[GENUS ANELLOVIRIDAE VIRUSES IN CHRONIC LIVER DISEASE]

AIM

Viruses from genus Anelloviridae (TTV, TTMDV and TTMV) are small DNA viruses that are widespread in human popu- lation. Data on tissue tropism, cell localization and morphometry of anelloviruses are scarce. The purpose of this study was to determine the prevalence of TTV, TTMDV and TTMV in persons with liver disease and in healthy individuals, as well as electron-microscopic verification of Anelloviridae species.

METHODS

Detection of anelloviral DNA was performed in serum samples from 203 patients with liver diseases of various etiology and 115 voluntary blood donors using PCR with primers allowing to differentiate TTV, TTMDV TTMV based on the length of amplified fragment. Histopathological and electron microscopic studies were performed for liver biopsy specimens from 203 patients with liver disease.

RESULTS

High prevalence (70-90%) of all three anelloviruses in healthy individuals and patients with liver disease was demonstrated, with high frequency of triple TTV, TTMDV and TTMV infection (52.2-55.7%). Electron-microscopic study of liver biopsy specimens from TTMDV monoinfected patients gave a submicroscopic image of TTMDV virions with diameter 35.86 ± 2.04 nm. Electron microscopic studies confirmed the nature of liver damage in TTMDV monoinfection: accumulation of virus in the hepatocytes, significant cyropathy with enlightenment matrix of the cytoplasm and reduction of intracellula organelles involved in protein synthesis, portal and perivascular perisinusoidal fibrosis. TTV, TTMDV and TTMV virions were dentified in hepatocytes, confirming these viruses to be hepatotropic.

CONCLUSION

Our results demonstrate that anelloviruses are lymphotropic viruses, individual genotypes of those might be hepatotropic and pathogenic to liver.

[FAMILIAL CLUSTERS OF HEPATITIS DELTA IN ENDEMIC REGION (REPUBLIC TYVA)]

AIM

Clinical and virological characteristic of hepatitis delta familial clusters in region of Russia that is endemic for this infection (Republic Tuva).

MATERIALS AND METHODS

Total 383 patients with HBV/HDV coinfection and their family members (3 generations) were followed. Serum samples for HDV and HBV markers testing were available for 42 patients from 18 families. HBsAg, anti-HBc, HBeAg, anti-HBe and anti-HDV were tested using commercial ELISA tests; HDV RNA and HBV DNA were tested using in house nested PCR tests.

RESULTS

30 family (63 people) clusters were identified, in which close living persons have been infected with HDV and HBV. The biological material for determining of HDV and HBV markers has been available from 18 families (42 people belonging to 1-3 generations (parents and children, husband and wife, brother and sister). The mean age was 35 ± 14 years (10-58 years). Chronic hepatitis (CH) was in 30 (71.4%) patients, liver cirrhosis (LC)--in 10 (23.8%) and HCC was developed in 2 (4.8%) person on the background of long infections. The incidence of HBeAg was 14.3% (6/42), HBV DNA--19% (8/42); HDV RNA--35.7% (15/42). In 2 cases (mother) replication markers of both viruses were found, it contributed to the increased risk of infection in children. So HDV RNA was detected in the blood serum of their daughters (15 and 17), that does not exclude the possibility of vertical transmission. An illustration describes four families.

CONCLUSION

The epidemic process of delta infection in the Republic of Tyva is characterized by intrafamilial infection of HBV and HDV.

Comparative characterization of two tests for measurement of hepatitis B virus DNA in the blood serum and plasma, based on the use of two different detection methods

Two tests for measurements of hepatitis B virus DNA in human serum and plasma, VERSANT HBV 3.0 (based on the use of branched DNA chains) and Biotitre-B (a real-time PCR variant), were compared. Serum specimens from patients (n=56) with documented viral hepatitis were tested. For specimens with DNA values in the linear range in both tests the correlations were evaluated by Pearson's method. The sensitivity of the two tests, and reproducibility of the results of HBV DNA measurements were evaluated using a panel of recombinant virus DNA dilutions with a step of 1 lg HBV DNA copies per ml (from 7 to 3 lg). Three measurements for each concentration of the reference sample were carried out in each test. Clinical specificity of the two tests was evaluated by the analysis of HBV-negative serum samples, collected from donors not reactive by HBsAg and anti-HBc (n=60). Of 56 samples with documented infection, the results of testing by VERSANT HBV 3.0 and Biotitre-B did not agree in 4 (7.1%) samples. Pearson's correlation coefficient of for results obtained in VERSANT HBV 3.0 and Biotitre-B in linear range for both tests was 0.712. Evaluation of reproducibility of the tests using a panel of recombinant HBV DNA showed higher reproducibility of VERSANT HBV 3.0 test with coefficient of variations from 0.79 to 2.79% vs. 2.39-10.69% for Biotitre-B reference test. All 60 serum samples from donors areactive by HBsAg and anti-HBc were negative by HBV DNA when tested by VERSANT HBV 3.0 and Biotitre-B. Hence, clinical specificity of both tests was 100%. The results indicate high specificity of both tests and good agreement of their results, the reproducibility of VERSANT HBV 3.0 test being higher.

Significance of sexual route of transmission of hepatitis B and C in Russia

It is generally understood that hepatitis B and hepatitis C may be sexually transmitted. During the last decade there was a sharp growth of hepatitis B and C in Russia. In comparison to 1992 the incidence of hepatitis B in Russia rose two-fold and in 1999 there were 43.31 cases per 100,000 of population (in some cities up to 150/100,000 and even more). The incidence of hepatitis C in 1999 (19.31 per 100,000 of population) rose to six times more than in 1994. At the same time there was a dramatic growth in syphilis and other sexually transmitted infections in Russia. The proportion of sexual transmission of hepatitis B virus (HBV) and hepatitis C virus (HCV) compared with other routes of transmission increased. According to the data from Moscow City Centre of Epidemiology during the last two years, up to 40% cases of HCV and HBV were sexually transmitted. The most dramatic growth of registered cases of hepatitis was seen among the sexually active population aged 14-29. Confirmation of the sexual route of transmission of HBV and HCV in teenagers was seen when the results of the study showed various markers of HBV and HCV to be significantly more common among sexually active (n = 45) than sexually inactive (n = 341) teenagers (13.33% vs. 4.39% for HBsAg; 46.67% vs. 12.61% for HBsAg+anti-HBs+anti-HBc; 9.47% vs. 3.95% for anti-HCV, respectively).

Antibody to hepatitis E virus in HIV-infected individuals and AIDS patients

Antibody to hepatitis E virus of IgG class (anti-HEV IgG) is regularly detected in industrialized countries, where HEV is non-endemic, at levels not exceeding 2-3%; seropositive individuals are often found in certain groups of patients and professionals exposed to an increased risk of blood-borne infections. The present study was aimed at the identification of anti-HEV IgG in patients with human immunodeficiency virus (HIV) infection, including acquired immune deficiency syndrome (AIDS), living in Russia and Belarus, an area of low anti-HEV prevalence with a moderate spread of HIV infection and AIDS. In Russia, 13 out of 117 HIV-infected patients (11.1%) were found to be anti-HEV seropositive. This differed significantly from the frequency observed in the normal population (1.7%) but not from the frequency in a matching control, high-risk group consisting of male prisoners (8.0%). No difference in the frequency of anti-HEV IgG seropositivity was found between groups of HIV-infected men subdivided by sexual orientation. The rate of anti-HEV seropositivity increased with the progression of HIV infection, reaching 43.3% in AIDS patients and 38.1% in those who died from AIDS. In Belarus, anti-HEV IgG seropositivity was not found among 20 HIV-infected subjects nor among individuals from the control risk group, which consisted of 25 intravenous drug users. In conclusion, HEV infection may have common transmission mechanisms (risk factors) with HIV infection rather than represent an additional opportunistic infection in AIDS.

Serological survey on hepatitis E virus infection in an endemic area: diagnosis potential of enzyme immunoassay for detection of IgG antibody

BACKGROUND

Hepatitis E is a major cause of acute icteric disease widespread in tropical and sub-tropical regions but rarely occurring in industrialized countries. Recently solid-phase enzyme immunoassays with recombinant antigens have been introduced for diagnosis of this infection.

OBJECTIVES

The aim of this study was to evaluate the diagnostic potential of a newly developed Abbott test for the detection of IgG class antibodies to hepatitis E virus (anti-HEV IgG) in hepatitis patients and 'normal' individuals.

STUDY DESIGN

Sera taken from hepatitis patients and individuals without liver disorders in endemic (Kirghizstan and Uzkbekistan) versus non-endemic (Moscow) areas were investigated. In parallel IgG class antibodies to hepatitis A virus (anti-HAV IgG) were determined by an enzyme immunoassay with native HAV antigen.

RESULTS

In five groups comprising altogether 86 suspected hepatitis E patients from endemic area the rate of anti-HEV IgG seropositivity varied from 85% to 17%. In Moscow anti-HEV IgG was found in one patient (who also had acute hepatitis B) out of 19. Anti-HEV IgG persisted in an experimentally infected volunteer for at least 12 years after the acute disease. Among the individuals without liver disorders eight out of 173 (4.6%) showed anti-HEV IgG seropositivity in Kirghizstan while there was only one seropositive out of 165 (0.6%) in Moscow. In contrast, anti-HAV IgG were frequently present in the residents of both areas: in Kirghizstan over 90% of individuals from young age groups already had these antibodies; in Moscow the rate of anti-HAV IgG seropositivity constantly increased from 31% in the youngest age group to almost 85% in the oldest one.

CONCLUSION

Prevalence of anti-HEV antibodies was unexpectedly low in endemic area; in Moscow anti-HEV IgG was found only in single cases. Anti-HEV IgG seropositivity in a single serum sample could be of certain diagnostic value in non-endemic areas.