A comparative analysis of the prevalence of antibodies to the hepatitis E virus (Hepeviridae: Paslahepevirus) among residents of the Amur Region with different levels of zoonotic risk of infection

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Introduction

Despite the predominantly endemic nature of the infection caused by the hepatitis E virus (HEV) in countries with poor sanitation and limited access to clean drinking water, there has been an increase in recent decades in the number of sporadic cases and outbreaks of HEV infection in industrialized countries, including Europe, North America, and Asia [1–3]. In the Russian Federation, official registration of hepatitis E cases began in 2013, and according to data on infectious and parasitic diseases, the number of registered hepatitis E cases during this period ranged from 57 to 182 per year [4]. However, these figures do not reflect the true prevalence of the infection, as evidenced by the relatively high prevalence of IgG antibodies to HEV (anti-HEV) among the general population of the Russian Federation: ranging from 2.7% to 16.4%, depending on the region surveyed [5]. The causative agent of the infection–Paslahepevirus balayani (genus Paslahepevirus, family Hepeviridae)–is represented by 8 genotypes, 4 of which (1, 2, 3, and 4) are capable of causing HEV infection in humans [6]. The primary route of transmission for HEV genotypes 1 and 2 is through the consumption of contaminated drinking water, whereas infection with genotypes 3 and 4 usually occurs through the consumption of undercooked pork or wild game meat. The main reservoirs of the zoonotic HEV genotypes 3 and 4 are pigs, wild boars, and deer [7]. Cases of HEV transmission via contaminated blood products and during organ transplantation have also been reported [8, 9]. The Amur Region is characterized by a well-developed pig industry, as well as traditional reindeer herding among the indigenous peoples of the North. The overlap of the ranges of various ungulate species—potential zoonotic reservoirs of HEV–makes the Amur Region a unique area in terms of interspecies transmission of the virus and creates potential risks of HEV transmission from animals to humans; however, no comparative studies have previously been conducted to assess the prevalence and risk factors for HEV transmission in the region.

The aim of this study is to conduct a comparative analysis of the prevalence of anti-HEV antibodies among residents of the Amur Region with varying levels of zoonotic risk of HEV infection (those living in areas with developed pig farming and traditional reindeer herding), as well as among pig and reindeer (Rangifer tarandus) populations.

Materials and methods

Blood serum samples

Between February and May 2025, 1,114 blood serum samples were collected in various regions of the Amur Region from generally healthy residents over 1 year of age, divided into three groups: residents of Settlement No. 1 (n = 90) with a major pig farming complex (primarily pig farm employees and their relatives); residents of Settlement No. 2 (n = 102), who regularly consume reindeer meat and are primarily engaged in reindeer herding; and residents of other areas of the Amur Region with no apparent zoonotic risk of HEV infection (n = 922).

All participants provided written informed consent to participate in the study and completed a questionnaire, which included a question about the consumption of wild boar/reindeer meat over the past 6 months.

Previously, in 2022–2023, 197 blood sera and paired fecal samples were collected from pigs aged 1.5 to 28 weeks at the pig farm in Settlement No. 1, and in 2022 – 97 blood serum samples were collected from reindeer (Rangifer tarandus) aged 1 year to 18 years, which are grazed and kept in the region of Settlement No. 2.

Detection of markers of HEV infection

Human blood serum was tested by enzyme-linked immunosorbent assay (ELISA) for the presence of anti-HEV IgG and IgM antibodies using the commercial reagent kits DS-ELISA-ANTI-HEV-G and DS-ELISA-ANTI-HEV-M (Diagnostic Systems-Stolitsa LLC, Russia) according to the manufacturer’s protocol.

Animal blood serum was tested for anti-HEV IgG using the DS-ELISA-ANTI-HEV-G reagent kit (Diagnostic Systems-Stolitsa LLC, Russia) according to the manufacturer’s protocol; however, instead of the conjugate from the kit, rabbit polyclonal antibodies against deer or pig IgG (depending on the serum being tested), labeled with horseradish peroxidase (KPL, USA) at dilutions of 1 : 100 and 1 : 100,000 in phosphate-buffered saline, respectively, were used. Samples with an optical density (OD) exceeding the threshold value (0.20 plus the mean OD of the negative controls) were considered reactive. Regardless of the ELISA results, all deer blood sera (n = 97) as well as pig fecal samples (n = 197) were tested for the presence of HEV RNA in parallel using two in-house methods: nested polymerase chain reaction (PCR) [5] and real-time reverse transcription-PCR using primers and a probe developed by N. Jothikumar et al. [10].

Statistical analysis

Statistical analysis of the collected data was performed in the Google Colab cloud environment using the following Python libraries (version 3.12): pandas (data processing), statsmodels (logistic regression and confidence intervals), scipy.stats (Mann–Whitney U test, chi-square test, exact Fisher’s test), statsmodels.stats.proportion (confidence interval (CI)), matplotlib, and seaborn (visualization).

Descriptive statistics included calculations of the arithmetic mean (M), standard deviation (SD), as well as the median (Me) and interquartile range [Q₁; Q₃]. For the categorical variable of the prevalence of anti-HEV IgG and anti-HEV IgM antibodies, the mean and 95% CI were calculated. A statistical analysis using Fisher’s exact test was performed to compare the prevalence of anti-HEV detection. To test for a statistical association between age group and seropositivity in animals, Pearson’s χ² test was applied.

To identify factors associated with seropositivity among participants, a comparative analysis was conducted using the Mann–Whitney U test (for the continuous variable of age) and Pearson’s χ² test for categorical variables; in cases where the expected frequencies in any cell of the contingency table were less than 5, Fisher’s exact test was used.

Binary logistic regression was used to assess the independent contribution of each risk factor to the probability of the presence of anti-HEV IgG in human serum samples. The model assessed factors such as gender, age, residence in Region 1, residence in Region 2, consumption of wild boar or deer meat in the past 6 months, and a history of blood transfusions. Predictors were selected using the forced inclusion method, based on the study’s objectives and data from the literature. The results of the logistic regression are presented as regression coefficients (B), standard errors, p-values, and odds ratios (OR) with 95% CI. The percentage change in odds was calculated using the formula:

Percentage change in odds = (ОR − 1) × 100%.

Ethical approval

The authors confirm compliance with institutional and national standards for the use of laboratory animals in accordance with the Consensus Author Guidelines for Animal Use (IAVES, July 23, 2010). The study was conducted with the voluntary informed consent of the Volunteers. The study protocol was approved by the Ethics Committee of the Amur State Medical Academy under the Ministry of Health of Russia (Protocol No. 2, June 26, 2023).

Results

Prevalence of Anti-HEV antibodies in the Generally Healthy Population of the Amur Region

The demographic data for generally healthy residents of the Amur Region, who participated in the study, are presented in Table 1.

 

Table 1. Demographic data of study participants

Таблица 1. Демографические характеристики участников исследования

Groups of generally healthy residents of the Amur Region Исследуемая подгруппа условно здорового населения Амурской области	Number of participants Число участников	M/F ratio Соотношение М/Ж	Age / Возраст
			M ± SD	Ме [Q1; Q3]
Settlement No. 1 Поселение № 1	90	1 : 1.2	28.1 ± 18.5	24 [11; 43]
Settlement No. 2 Поселение № 2	102	1 : 2.5	44.1 ± 20.4	46 [32; 61]
Other areas of the Amur Region Прочие регионы Амурской области	922	1 : 1.4	29.2 ± 21.1	24 [11; 47]

 

The prevalence of anti-HEV IgG antibodies among residents of Settlement No. 1 was 14.4% (13/90, 95% CI 8.6–23.2), which was significantly higher than among residents of Settlement No. 2 (3.9%, 4/102, 95% CI 1.5–9.6; p = 0.0117) and other regions of the Amur Region (3.8%, 35/922, 95% CI 2.7–5.2; p = 0.0001) (Fig. 1). A nearly significant trend toward a higher prevalence of IgM antibodies (a marker of recent HEV infection) was also observed among residents of Settlement No. 1 compared with other regions of the Amur Region (3.3%, 3/90, 95% CI 1.1–9.3 versus 0.8%, 7/922, 95% CI 0.4–1.6; p = 0.0516).

 

Fig. 1. Anti-HEV IgG and IgM antibody detection rates among general population in various districts of the Amur Region. Vertical lines indicate 95% CI values; significant p-values (Fisher’s exact test) are highlighted in red.

Рис. 1. Частота выявления маркеров анти-ВГЕ IgG и IgM среди условно здорового населения, проживающего в разных районах Амурской области. Вертикальными линиями отмечены значения 95% ДИ, красным шрифтом выделены достоверные p-значения (точный критерий Фишера).

 

The distribution of participants by age group showed that the proportion of those testing positive for anti-HEV IgG antibodies increases with age from 1.1% to 9.5%. Pairwise comparisons of age groups also revealed statistically significant differences: in particular, the prevalence in the 1–18-year-old group was significantly lower (1.1%, 5/466, 95% CI 0.46–2.49) than in the 19–40 age group (3.4%, 8/236, 95% CI 1.73–6.55; p = 0.040) and those aged 40 and older (9.5%, 39/412, 95% CI 7.0–12.68; p < 0.0001) (Table 2). Notably, there was also a trend toward an increase with age in the proportion of individuals who were positive for anti-HEV IgM: from 0.2% to 1.7%; however, the differences between the 1–18-year-old and 19–40-year-old groups, as well as between the 19–40-year-old and over-40-year-old groups, were not statistically significant. Nevertheless, anti-HEV IgM antibodies were significantly more common in the group of participants over 40 years of age than among children and adolescents aged 1–18 years (1.7%, 7/412, 95% CI 0.83–3.47, and 0.2%, 1/466, 95% CI 0.04–1.21; p = 0.029).

 

Table 2. Anti-HEV IgG and IgM antibody detection rates among three age groups of the general population of the Amur Region

Таблица 2. Частота выявления маркеров анти-ВГЕ IgG и IgM среди трех возрастных групп условно здорового населения Амурской области

Age group, years Возрастная группа, лет	Anti-HEV IgG positive Анти-ВГЕ IgG-положительные		p (Fisher exact test / точный критерий Фишера)	Anti-HEV IgM positive Анти-ВГЕ IgM-положительные		p (Fisher exact test / точный критерий Фишера)
	n/N	% (95% CI / ДИ)		n/N	% (95% CI / ДИ)
1–18	5/466	1.1 (0.46–2.49)	0.040* < 0.0001**	1/466	0.2 (0.04–1.21)	0.263* 0.029**
19–40	8/236	3.4 (1.73–6.55)	0.004**	2/236	0.8 (0.23–3.04)	0.499**
Over 40 Старше 40	39/412	9.5 (7.0–12.68)		7/412	1.7 (0.83–3.47)

Note. * – when compared with the 19–40 age group; ** – when compared with the over-40 age group. Significant differences are highlighted in bold.

Примечание. * – при сравнении с группой 19–40 лет; ** – при сравнении с группой старше 40 лет. Достоверные отличия выделены полужирным шрифтом.

 

It should be noted that, according to survey data, 7.7% (71/922) of residents in other regions of the Amur Region had consumed wild boar or deer meat within the past 6 months; however, the prevalence of anti-HEV antibodies among them was at the same level as among participants who reported not consuming such meat: anti-HEV IgG – 4.2% (3/71) and 3.8% (32/851, p > 0.05), anti-HEV IgM – 1.4% (1/71) and 0.7% (6/851, p > 0.05), respectively.

In a multivariate logistic regression analysis, the following factors were found to be independent predictors of a past HEV infection, as indicated by the presence of anti-HEV IgG: the participants’ age (OR = 1.06, 95% CI 1.04–1.07; p < 0.001) and residence in Settlement No. 1 (OR = 6.32, 95% CI 3.01–13.28; p < 0.001). A history of blood transfusions among participants also showed a trend toward increased risk (OR = 2.1), but this effect did not reach statistical significance (p = 0.12). The remaining factors studied, such as the participants’ sex, residence in Settlement No. 2, and consumption of wild boar or reindeer meat within the past 6 months, showed no association with the presence of anti-HEV IgG antibodies (Fig. 2 a).

 

Fig. 2. Forest plot visualization of logistic regression analysis: factors associated with the detection of anti-HEV IgG (a) antibodies and anti-HEV IgM antibodies (b). The horizontal line represents the odds ratio (OR) on a logarithmic scale. The vertical dashed line corresponds to an OR value of 1 (the line of no effect). The red dots represent the point estimate of the odds ratio for each factor, with 95% confidence intervals (CI) indicated (horizontal lines). If the horizontal line intersects the vertical line (OR = 1), the factor is not statistically significant (p > 0.05); if the line lies entirely to the right of 1, the factor statistically significantly increases the odds of seropositivity. The p-value obtained from the logistic regression model, as well as the OR value and 95% CI, are indicated to the right of each line. Note: The OR for age (a continuous predictor) shows the change in odds per year of life and has a cumulative effect.

Рис. 2. Визуализация результатов логистической регрессии с помощью Forest plot: факторы, ассоциированные с появлением анти-ВГЕ IgG (а) и анти-ВГЕ IgM (б). Горизонтальная линия отражает отношение шансов (OШ) в логарифмическом масштабе. Вертикальная пунктирная линия соответствует значению ОШ, равному 1 (линия отсутствия эффекта). Красными точками отображается точечная оценка отношения шансов для каждого фактора с указанием 95% доверительных интервалов (95% ДИ; горизонтальные линии). Если горизонтальная линия пересекает вертикальную линию ОШ = 1, то фактор не является статистически значимым (p > 0,05), в случаях если линия целиком лежит правее 1, то фактор статистически значимо повышает шансы серопозитивности. Справа от каждой строки указано p-значение, полученное из модели логистической регрессии, а также значение ОШ и 95% ДИ. Примечание: ОШ для возраста (непрерывного предиктора) показывает изменение шансов за один год жизни и имеет кумулятивный эффект.

 

Calculation of the percentage change in odds showed that a 1-year increase in participants’ age increases the odds of exposure to HEV (in this case, the odds of having anti-HEV IgG antibodies) by 5.5%, holding all other factors in the statistical model constant. The median age in the anti-HEV IgG-positive group was 52 years (interquartile range [41; 64]), and in the seronegative group, it was 26 [11; 47] years.

In the study sample, only 0.9% (10/1,114) of participants had anti-HEV IgM antibodies, which represents an extremely small number of events for multivariate analysis. Despite these limitations, the analysis showed that, as with anti-HEV IgG antibodies, age and residence in Settlement 1 were statistically significantly associated with the presence of anti-HEV IgM (age: OR = 1.04, 95% CI 1.0–1.07; p = 0.020; Settlement 1: OR = 6.2, 95% CI 1.5–25.6; p = 0.013). The remaining factors analyzed (gender, consumption of wild boar/deer meat, and blood transfusions) showed no significant association, which may be due to either the absence of an effect or an insufficient number of events (Fig. 2 b).

Detection of Anti-HEV IgG in Animals

The prevalence of anti-HEV IgG antibodies in blood serum samples from pigs kept at the pig farm in Settlement No. 1 was 96.4% (190/197, 95% CI 92.8–98.3). In blood serum samples from reindeer (Rangifer tarandus) grazed and kept in Settlement No. 2, the detection rate of anti-HEV IgG antibodies was 92.8% (90/97, 95% CI 85.8–96.5). All blood sera from the animals tested negative for HEV RNA.

The distribution of the detection rate of anti-HEV IgG antibodies by animal age is shown in Fig. 3.

 

Fig. 3. Age-specific anti-HEV IgG antibody detection rates in pigs (a) and reindeer (b). Vertical lines indicate 95% CI values.

Рис. 3. Частота выявления анти-ВГЕ IgG среди свиней (а) и северных оленей (б) в зависимости от возраста животных. Вертикальными линиями отмечены значения 95% ДИ.

 

The Pearson’s χ² test was used to assess the relationship between HEV seropositivity and the age of the pigs. The results of the analysis showed no statistically significant differences between the age groups studied (χ² = 6.31; p = 0.098, degrees of freedom = 3), despite a slight trend toward a decrease in the frequency of anti-HEV IgG antibody detection among animals older than 8 weeks, which is most likely due to the natural decline in maternal antibodies in older animals.

In contrast, among reindeer, a statistically significant association was found between the animals’ age group and the seropositivity of the samples (Pearson’s χ² = 10.17; p = 0.017, degrees of freedom = 3) due to the relatively low prevalence of antibodies among one-year-old animals, which was 66.7% (6/9, 95% CI 35.4–87.9), whereas among older animals, the prevalence of anti-HEV antibodies exceeded 94%, with no statistically significant differences between age groups. Thus, it was demonstrated that reindeer become infected predominantly at an early age, and by 2 years of age, virtually all animals have antibodies.

Discussion

The prevalence of anti-HEV antibodies among the population of the Amur Region not involved in livestock farming–that is, excluding Settlements No. 1 and No. 2–averaged 3.8%, which corresponds to the average Russian seroprevalence rate for HEV (4.6%) obtained from previous surveys of various regions of the country. The increase in the prevalence of anti-HEV antibodies with age, observed among the population of the Amur Region, is also characteristic of the Russian Federation and other countries where HEV is not endemic [5].

In non-endemic areas for HEV, where human infection is associated with zoonotic HEV genotypes 3 and 4, the potential routes and factors of virus transmission are numerous and often difficult to identify. In this study, the strongest and most independent predictor of anti-HEV IgG seropositivity among residents of the Amur Region was the participants’ age: with each passing year, the odds of seropositivity increased by 5.5% (OR = 1.055). Living in Settlement No. 1 also increased the odds of HEV infection by 6.3 times compared to participants living outside this region, after controlling for all other variables (OR = 6.32), which indicates that pig farm workers and their family members are at increased risk of HEV infection.

Furthermore, the results of this study are consistent with the literature: for example, in the Republic of Moldova, 51.1% of pig farm workers tested positive for anti-HEV, while the corresponding figure among healthcare workers was 24.7%. The identified risk factors were cleaning in pig barns, assisting sows during farrowing, and length of professional experience [11]. Anti-HEV IgG antibodies were also significantly more common among the population living in regions of intensive pig farming in Germany compared to other regions of the country [12]. In the Russian Federation, the highest rates of HEV seroprevalence are also observed in the Belgorod Region—the center of domestic pig farming [5].

According to data we obtained earlier, the main period of infection among animals kept on pig farms occurs between 9 and 16 weeks of age [5]. In the current study, among pigs in this age group, as well as older pigs (20–28 weeks)—by which time HEV viremia typically subsides but antibodies persist—an extremely high detection rate of anti-HEV IgG antibodies was observed (93.5%, 101/108), indicating a widespread prevalence of HEV infection among the herd at the surveyed pig farm and exceeding the average seroprevalence rates reported in European studies: 49.8% in Germany [13], 65% in France [14], 68% in the Netherlands [15], 73% in Belgium [16] and 87% in Italy [17].

In this study, blood serum samples were collected at a pig farm with a herd of more than 3,000 head. The high seroprevalence (96.4%), observed at such a large facility, is consistent with data from Belgian studies, in which the prevalence of anti-HEV antibodies also depended on the size of the pig farms (ranging from 60% for herds of 100–200 animals to 94% for herds of more than 2,000 animals) [18]. It should be noted that the Belgian authors identified the following factors as associated with an increased risk of infection in pigs: a production system in which pigs are raised on a single farm from farrowing to slaughter, the practice of free-range rearing, and inadequate hygiene in the facilities [18]. The absence of positive HEV RNA findings in samples from pigs is also likely explained by the high seroprevalence—on the surveyed farm, it appears that piglets become infected at an earlier stage, and by the time of testing, the virus had been eliminated and anti-HEV antibodies had developed in most animals.

Furthermore, this study revealed an extremely high proportion of seropositive reindeer (92.8%, 90/97) in Settlement No. 2 of the Amur Region, indicating intense circulation of HEV or an antigenically related virus among the animal population. Differences in seroprevalence between age groups suggest that reindeer are most likely to become infected during their first and second years of life. In our previous studies on the prevalence of anti-HEV antibodies in reindeer in the Republic of Sakha (Yakutia) using the same ELISA methodology, significantly lower rates were observed: the prevalence of anti-HEV antibodies was 12.0% (23/191) and 15.5% (77/497) in 2019 and 2023, respectively [19, 20]. It is important to emphasize that in the Republic of Sakha (Yakutia), due to harsher climatic conditions and a number of other limiting factors, there is a lower population density or a complete absence of both wild ungulates of other species and domestic pigs, particularly in the northern regions where research samples were collected (Oymyakon, Anabar, and Ust-Yansky districts). The data obtained in the Amur Region also exceeded the figures from foreign studies, where the prevalence of anti-HEV IgG antibodies in semi-domesticated reindeer was significantly lower (8.8% in Canada, 15.7% in Norway) [21, 22]. It should be noted that, despite the lack of data on the detection of anti-HEV antibodies among reindeer, HEV RNA has not yet been detected in these animals. Apparently, standard primer sets for detecting HEV genotypes 3 and 4 do not allow for the detection of a potentially more divergent virus, which requires the use of a metagenomic approach for its detection.

The extremely high seroprevalence of HEV among reindeer in the Amur Region (92.8%) may be explained by the possibility of constant contact between semi-domesticated reindeer and other ungulates (roe deer, red deer, and spotted deer, wild boars) due to the overlap of their ranges and the occurrence of interspecies transmission of the virus. Additionally, pig farms and their wastewater may serve as a potential source of HEV infection for reindeer, either directly or via wild migratory ungulates acting as an intermediate host. It was previously demonstrated that, using Bayesian analysis [23], the possibility of interspecies transmission from domestic pigs to certain deer species and the sustained circulation of HEV genotypes 3 and 4 among the latter in the wild.

It is important to note that despite the extremely high proportion of seropositive reindeer (92.8%) in Settlement No. 2 of the Amur Region, reindeer herders and their family members were not a risk group for HEV infection. It appears that pigs are a much more common source of HEV for humans than reindeer, likely due to a higher viral concentration [24] and/or differences in the intensity of contact with animals and their feces when raising pigs versus semi-domesticated reindeer. Nevertheless, reindeer appear to be a source of HEV for humans, given the presence of anti-HEV IgG in reindeer herders in the Republic of Sakha (Yakutia), who have virtually no contact with other species of ungulates [19].

In addition, the antibodies detected in reindeer in the current study may also indicate the circulation of an antigenically similar virus among them, since the capsid proteins of Paslahepevirus balayani are capable of exhibiting cross-reactivity with other members of the family Hepeviridae [25–27]. Thus, isolating the virus from reindeer and conducting molecular genetic analysis is a necessary next step in the research.

In addition to zoonotic risk factors, this study also assessed the impact of a history of blood transfusions. The risk of HEV transmission through blood transfusion has been demonstrated in a number of international studies and poses a particular threat to immunocompromised patients [28]. It was previously shown that the prevalence of HEV RNA among blood donors in the Russian Federation is 0.024% (the risk of receiving a blood transfusion containing HEV is 1 case per 4,081 donations) [29], which underscores the need to implement HEV RNA screening of donated blood. In the current study, we also found that blood transfusion is associated with an increased risk of exposure to the virus; however, this effect did not reach statistical significance, most likely due to the small number of cases in the group of anti-HEV IgG- and IgM-positive participants with a history of blood transfusions, which demonstrates the need for targeted studies on the role of blood transfusions in larger samples.

Study limitations. This study had several limitations. First, the absence of positive results for HEV RNA detection and subsequent molecular genetic sequence analysis makes it impossible to determine the genotypes of circulating viruses and to establish a genetic link between HEV isolates from pigs, deer, and humans. Second, the use of a modified test system for detecting antibodies in animals may limit the comparability of the results conducted abroad, due to the lack of an international standard for animal anti-HEV antibodies that would allow for the validation of test systems for detecting anti-HEV antibodies in animals (similar to what has been done for diagnostic assays for detecting anti-HEV antibodies in human samples). Third, the relatively small number of participants in the samples of anti-HEV IgG- and IgM-positive individuals limited the statistical power when analyzing rare events (anti-HEV IgM positivity, blood transfusions).

Conclusion

The seroprevalence rate of HEV in the Amur Region was found to be in line with the Russian average. The trend in antibody accumulation with age also corresponds to the trend observed nationwide. Pig farm workers and their family members are at increased risk of HEV infection, confirming the role of pigs as the primary zoonotic reservoir of HEV in the Amur Region. The data obtained justify the need to develop and implement measures to prevent HEV infection among workers at pig farms and their family members. Despite the extremely high proportion of seropositive reindeer in the Amur Region (92.8%), indicating the intensive circulation of HEV or an antigenically related virus among them, reindeer herders and their family members are not a high-risk group for HEV infection, which indirectly suggests the circulation among reindeer of a virus distinct from zoonotic HEV genotypes 3 and 4.

About the authors

Vera S. Kichatova

Central Research Institute of Epidemiology; I. Mechnikov Research Institute of Vaccines and Sera

Author for correspondence.
Email: vera_kichatova@mail.ru
ORCID iD: 0000-0002-7838-6965

Cand. Sci (Med.), senior researcher at the laboratory of molecular epidemiology of viral hepatitis, senior researcher fellow of the laboratory of viral hepatitis

Russian Federation, 111123, Moscow; 105064, Moscow

Anastasia V. Zotova

Amur state medical Academy of the Ministry of Public Health of Russia

Email: 30161zotova@mail.ru
ORCID iD: 0009-0003-4984-8491

Cand. Sci. (Med.), Associate Professor of the Department of Infectious Diseases with Epidemiology and Dermatovenereology

Russian Federation, 675001, Blagoveshchensk

Ilya A. Potemkin

Central Research Institute of Epidemiology; I. Mechnikov Research Institute of Vaccines and Sera

Email: axi0ma@mail.ru
ORCID iD: 0000-0001-7559-4219

Cand. Sci. (Med.), senior researcher at the laboratory of molecular epidemiology of viral hepatitis, senior researcher fellow of the laboratory of viral hepatitis

Russian Federation, 111123, Moscow; 105064, Moscow

Maria A. Lopatukhina

Central Research Institute of Epidemiology; I. Mechnikov Research Institute of Vaccines and Sera

Email: m.lopatukhina@gmail.com
ORCID iD: 0000-0001-6853-4154

research fellow at the laboratory of molecular epidemiology of viral hepatitis, research fellow of the laboratory of viral hepatitis

Russian Federation, 111123, Moscow; 105064, Moscow

Fedor A. Mobarhan

Central Research Institute of Epidemiology; I. Mechnikov Research Institute of Vaccines and Sera

Email: 1amfa@bk.ru
ORCID iD: 0000-0002-1838-8037

research fellow at the laboratory of molecular epidemiology of viral hepatitis, research fellow of the laboratory of viral hepatitis

Russian Federation, 111123, Moscow; 105064, Moscow

Elena Y. Malinnikova

I. Mechnikov Research Institute of Vaccines and Sera

Email: malinacgb@mail.ru
ORCID iD: 0000-0002-5501-5707

MD, PhD, DSc, Associate Professor, leading researcher, laboratory of viral hepatitis

Russian Federation, 105064, Moscow

Sergey V. Samokhvalov

Veterinary Administration of the Amur Region

Email: samohvalov.sv@mail.ru
ORCID iD: 0009-0009-3423-6680

Head

Russian Federation, 675001, Blagoveshchensk

Olga P. Kurganova

Department of Rospotrebnadzor for the Amur Region

Email: naspdo@mail.ru
ORCID iD: 0000-0003-3010-3054

Cand. Sci. (Med.), head, Chief state sanitary doctor for the Amur Region

Russian Federation, 675002, Blagoveshchensk

Karen K. Kyuregyan

Central Research Institute of Epidemiology; I. Mechnikov Research Institute of Vaccines and Sera

Email: karen-kyuregyan@yandex.ru
ORCID iD: 0000-0002-3599-117X

PhD, DSc, Professor of the Russian Academy of Sciences, head of the laboratory of molecular epidemiology of viral hepatitis, leading researcher of the laboratory of viral hepatitis, Professor of the Department of Microbiology

Russian Federation, 111123, Moscow; 105064, Moscow

Vasiliy G. Akimkin

Central Research Institute of Epidemiology

Email: crie@pcr.ru
ORCID iD: 0000-0003-4228-9044

Dr. Sci. (Med.), Professor, Academician of the Russian Academy of Sciences, Director

Russian Federation, 111123, Moscow

Mikhail I. Mikhailov

Central Research Institute of Epidemiology; I. Mechnikov Research Institute of Vaccines and Sera

Email: michmich2@yandex.ru
ORCID iD: 0000-0002-6636-6801

MD, PhD, DSc, Academician of the Russian Academy of Sciences, Chief Researcher of the laboratory of molecular epidemiology of viral hepatitis, Head of the laboratory of viral hepatitis

Russian Federation, 111123, Moscow; 105064, Moscow

References

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