Seroprevalence of hepatitis E virus in Estonia, 1994 to 2006, a pilot study

Valentina TefanovaTatjana Tallo, Tatiana Kuznetsova, Ljudmilla Priimägi,

Jevgenia Epstein, Kullo KutsarDepartment of Virology, NIHD, Tallinn, Estonia

Estonian Health BoardIX Annual Conference of the New VISBY Network

on Hepatitis C (HepC 2012)April 1-4, 2012, St.- Petersburg, Russia

Background Hepatitis E virus infection is an important public–health concern as a major cause of enterically transmitted hepatitis worldwide

The estimates of HEV infection prevalence: In regions of endemicity ranged between 3-26% In non-endemic regions ranges from 1 to 3%

Hepatitis E in developed countries is far more common than previously recognised and was also related with zoonotic transmission

V. Chandra et.al, 2008

In Estonia, according to order of Ministry of Social Affairs notification of hepatitis E should be introduced since 1997 However, HEV diagnostics is not still performed and the prevalence of anti-HEV antibodies in the general population has never been studied

To establish a starting point for further studies on HEV epidemiology as well as a molecular typing of HEV in Estonia we conducted a retrospective study on HEV prevalence in Estonia The objective of the study*

To determine the HEV presence and prevalence in a population sample from Estonia

The study was approved by the Tallinn Medical Research Ethics Committee

* Financial support: Estonian Health Board

HEV in Estonia

Materials

• Totally 1253 serum samples were randomly selected for study• From those: 763 samples were from patients with clinical signs of acute non-A-non-C hepatitis 176 - from hemodialysis patients 163 - from health care workers (HCW) with different speciality 151- from healthy individuals from urban and rural areas

• None of the tested samples were positive for anti-HIV, HBsAg, anti-HBc or anti-HCV

• The samples have been collected between 1994 and 2006 and stored at -70ºC before use at Department of Virology, NIHD

Methods

• Serum samples were tested for the presence of HEV IgG using recomWell HEV IgG ELISA kit (Mikrogen, Denmark)

• All HEV IgG positive sera were tested for HEV IgM antibodies by the recomWell HEVIgM, Mikrogen, Denmark

• Initially reactive samples both for IgG and IgM were retested and those with a repeatedly positive sera were considered positive

• For confirmation, positive sera were tested for anti-HEV IgG and IgM with an immunoblot assay (recomLine HEV IgG/IgM, Mikrogen)

• The prevalence of anti-HEV antibodies were calculated for each study, age and sex groups

• The chi-square test was used to analyze the differences. A P value of <0.05 was considered statistically significant

Applied antigens of the G1 and G3

Results 1:

Study groupsDate of collectin

Sex,M/F*

Mean ageM+SD, range

20-30 years

31-40 Years

41-50 years

51-60 years

≥61 years

Acute VH(non-Anon-C),

1994 - 2000, n=763378/385

46,2±15,020-91

135 150 165 178 135

Dialysis patients,1996 - 2006, n=176

105/7150,9±15,8

20-8028 15 36 35 62

Health care workers,2004, n=163

6/15738,6±12,3

20-7552 46 32 24 9

Healthy people 2003, n=151

5/14633,5±12,2

20-8172 62 1 3 13

Total, n=1253 494/75944,3±15,4

20-91287 273 234 240 219

Characteristics of studied groups

The study cohort composed:494 males aged 20-91, mean age 46.4±14.8 759 females aged 20-82, mean age 44.4±14.6

37% (459/1253) were older than 50 years, while 63% (794) were aged 50 years or less

Results 2: Prevalence of HEV IgG antibodies in the adult population of Estonia, 1994-2006

• In total, the anti-HEV prevalence was 3.2% (40/1253, 16 males, 24 females)• Anti-HEV IgM was found in 32.5% (13/40, 6 males, 7 females) out of anti-HEV positive samples• Overall, 27 sera samples were positive only for anti-HEV IgG

*Highest HEV prevalence - in healthy subjects (6.0%) followed by hemodialysis patients (5.1%)

anti-HEV positivity by studied groups

2.4

5.16.0

2.5

0

3.2

acute VH nAnC dial. pts HCW healthy people

%

*

Results: Prevalence of HEV IgG antibodies in the adult population of Estonia according to sex and age, 1994-2006

• a highest prevalence rate (5.9%) - in persons aged 60 years and over, p=0,01• overall seroprevalence rates for females - 3.16% and 3.24% - for males, p=0,920

0

1

2

3

4

5

6

7

20-30 31-40 41-50 51-60 ≥61

years

Males

Females

Total

5.9

Conclusions

The HEV IgG prevalence in adult Estonian population was 3.2%, being significantly higher in those aged 60 years and over

These preliminary results revealed the presence of HEV in Estonia and indicate that HEV should be considered as a possible cause of viral hepatitis

Since HEV diagnostic is not still performed in Estonia, there are urgent needs for introduction of robust protocol for diagnostics of HEV infection

It will be important to investigate whether or not sporadic cases of human hepatitis E exist in Estonia and, if so, which strains of HEV is responsible for them

In future, we plan to study of background HEV presence and prevalence both in the general population and in animals

Thank you for attention!