|Year : 2019 | Volume
| Issue : 2 | Page : 80-84
Seroprevalence of hepatitis E in healthy adults attending a tertiary care centre in Central Kerala
KG Chithira1, Reena John2, Prithi Nair3
1 Department of Microbiology, P K Das Institute of Medical Sciences, Ottapalam, Kerala, India
2 Department of Microbiology, Government Medical College, Kozhikode, Kerala, India
3 Department of Microbiology, Government Medical College, Thrissur, Kerala, India
|Date of Submission||19-Nov-2019|
|Date of Decision||21-Nov-2019|
|Date of Acceptance||20-Dec-2019|
|Date of Web Publication||17-Jan-2020|
Dr. K G Chithira
Department of Microbiology, P K Das Institute of Medical Sciences, Vaniamkulam, Ottapalam - 679 522, Kerala
Source of Support: None, Conflict of Interest: None
BACKGROUND: Hepatitis E virus (HEV) is emerging globally as a leading cause of an acute and generally self-limited hepatitis but is associated with a higher mortality, especially during pregnancy.
AIM: The purpose of this study was to estimate the seroprevalence of hepatitis E infection among adults with no previous history of jaundice/liver disease, in a tertiary care centre at Thrissur.
STUDY SETTING AND DESIGN: Hospital based cross sectional study was carried out in Government Medical College, Thrissur.
MATERIALS AND METHODS: Anti-HEV IgG was detected by using commercially available enzyme linked immunosorbent assay.
RESULT: The seroprevalence of HEV among blood donors and antenatal was approximately 1.2%.
CONCLUSION: HEV is less prevalent in this region. The low seropositivity among healthy adults shows an increased susceptibility to HEV infection. Since there is an increase in migrantsfrom high endemic area, screening for HEV in adult population especially pregnant females is desirable.
Keywords: Antenatal women, anti-hepatitis E virus immunoglobulin G, blood donors, Central Kerala, hepatitis E virus
|How to cite this article:|
Chithira K G, John R, Nair P. Seroprevalence of hepatitis E in healthy adults attending a tertiary care centre in Central Kerala. J Acad Clin Microbiol 2019;21:80-4
|How to cite this URL:|
Chithira K G, John R, Nair P. Seroprevalence of hepatitis E in healthy adults attending a tertiary care centre in Central Kerala. J Acad Clin Microbiol [serial online] 2019 [cited 2020 Feb 21];21:80-4. Available from: http://www.jacmjournal.org/text.asp?2019/21/2/80/276123
| Introduction|| |
Hepatitis E virus (HEV), a member of the Hepeviridae family, genus Hepevirus subtype, is an enterically transmitted (ET) hepatitis virus (hence, the name ET non-A, non-B). It is a non-enveloped virus with an icosahedral capsid and a size of approximately 27–34 nm. The virus has a single-stranded, positive-sense 7.2 kb RNA genome. It has at least four known mammalian genotypes (named 1–4), which belong to a single serotype. To date, genotypes 1 and 2 have been found only in humans that cause epidemic hepatitis and are transmitted by waterborne and faecal-oral means, whereas genotypes 3 and 4 have also been found in several mammalian species and infected humans as accidental host. HEV is now recognised globally as the emerging cause of ET hepatitis, both in epidemics and sporadic cases, especially in developing countries. As per the WHO, the seroprevalence in our country varies from 10% to 40%. HEV most frequently causes an acute and generally self-limited hepatitis but is associated with higher mortality, especially during pregnancy. HEV infection during pregnancy is associated with increased risk of prematurity, abortion, low birth weight, perinatal mortality, fulminant hepatitis and maternal mortality. This fact makes HEV unique among other hepatitis viruses. Hepatitis E is an underdiagnosed disease, in part due to less availability of data source. The sources of data on hepatitis E primarily consist of published articles, and these studies are the best methods that can be used to obtain data on epidemiology of HEV infection. Currently, there is a paucity of data on exposure to HEV in Indian population. Therefore, the present study is being carried out to determine the seroprevalence of subclinical HEV infection in a tertiary care centre in Central Kerala. Although immunoglobulin M (IgM) antibody is used as an acute-phase marker of HEV infection, immunoglobulin G (IgG) antibody to HEV is used to study the exposure to HEV in a given population.
| Materials and Methods|| |
Aim and objectives
To estimate the seroprevalence of hepatitis E infection among adult population which will include blood donors and antenatal women, in the age group of 18–45 years with no previous history of jaundice/liver disease, measured using IgG antibodies against HEV in Government Medical College, Thrissur.
Study setting and design
This hospital-based observational study was carried out in Government Medical College, Thrissur.
The study was conducted only after the approval and clearance from ethical committee, Government Medical College, Thrissur (B6-10471/2015/MCTCR dated 31 October 2015). Written informed consent was obtained from each study participants, and all patient details were kept confidential.
Blood donors and antenatal women, between 18 and 45 years of age attending Government Medical College, Thrissur, were included.
- Healthy adults between the age of 18 and 45 years attending Government Medical College, not suffering from any illness or any immunological disorders, with no previous history of jaundice/liver disease, and who were willing to take part in this study.
- Individuals with other hepatitis markers positive.
The study duration was one year (January 2016–December 2016).
Five hundred and sixteen healthy adults including blood donors and antenatals were taken in equal proportion in the age group of 18–45 years were included.
The purpose and methodology of the study were explained to all study participants, and informed consent was obtained. Pre-tested questionnaire [Annexure 1] was used to collect data on demographic profile and various risk factors associated with hepatitis E infection. The filled questionnaire and the blood samples of each study participants were coded to relate the results of ELISA for data entry and analysis. Blood sample (2 ml) was collected by venepuncture under aseptic precautions Serum was separated and stored at −40°C until the test was performed. Cold chain was maintained. Good laboratory practices were followed while conducting the tests. Anti-HEV IgG was detected using commercially available enzyme-linked immunosorbent assay. Test was performed using “DIAGNOSTIC KIT FOR HEV IgG ANTIBODY” (Bioneovan Co. Ltd) LOT 201608002 ELISA test kits, following protocols as per the manufacturer's instructions.
Sample size was calculated using the formula,
Sample size, n = 4pq/d 2
Where P = seroprevalence; q = 100 – p; d = allowable error = 20% of P.
Assuming the prevalence of HEV IgG as 17% and alpha error 20%, the calculated sample size at 5% significant level = 488. Hence, the minimum sample size was taken as 488.
| Results|| |
Study population included 516 subjects from two categories: blood donors and antenatal women. Out of the total 259 blood donors participated, three (1.2%) subjects were found to be positive and rest 256 (98.8%) of the subjects were negative. The number of subjects with protective antibody against hepatitis E was 1.2%. In case of antenatal women, three (1.2%) out of the total 257 subjects have been found IgG positive and were protected whereas the other 254 (98.8%) were negative. The prevalence of HEV was predominant among young adults of age group of 18–28 years (64.3%) with equal male and female preponderance. Individuals travelled outside Kerala or consumed food from outside showed slightly higher seroprevalence rates than other subjects. There was no difference noted between other factors. [Table 1] shows the distribution of study variables and IgG status (%).
|Table 1: Distribution of study variables and immunoglobulin G status (%)|
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| Discussion|| |
In most of the studies done worldwide, IgG antibody to HEV in healthy subjects has been used as a sero-epidemiologic tool to measure exposure to this virus. In developing countries like India, where HEV is endemic, the prevalence rates considered higher although with considerable variation between regions [Table 2]. Several studies conducted in various parts of India showed that seroprevalence of hepatitis E is more in the northern states compared to southern.
|Table 2: Seroprevalence of anti-hepatitis E virus immunoglobulin G in India|
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Some recent studies from Kerala showed HEV infection as the main cause of acute viral hepatitis. In a study on viral hepatitis conducted by Shamsundar et al., the percentage of samples positive for anti-HEV IgM ranged from 3% to 14.2% in various centres (data from 12 centres in Kerala in 2015).
As per the results of the present study, the HEV exposure rate is 1.2% which is lower, when compared with other studies done in southern Indian states. In a study by Daniel et al. conducted in Southern Indian population (including Tamil Nadu, Kerala, Karnataka and Andhra Pradesh), the overall seroprevalence was found to be 4% among their study population. The main reason for these differences in prevalence could have been due to small sample size. Other reasons are good hygiene, better social status and less endemicity of virus in the study population.
Studies on blood donors showed a varied seroprevalence rate. Studies on hepatitis E seroprevalence in Europe showed an estimated range from 0.6% to 52.5%, which included study by Schnegg et al. with a seroprevalence of 4.9% in Swiss blood donors and by Cleland et al. with seroprevalence of 4.6% in Scottish blood donors. The present study showed a seroprevalence of 1.2% among the blood donors which was comparable to the studies mentioned.
When compared with studies on pregnant women conducted in other part of the country, the present study showed a lower prevalence (1.2%) of anti-HEV IgG than other southern states (8%). Other studies from Lucknow  and Pune  reported a much higher prevalence in adult population (40%–50%). It is noted that, out of the three positives among the antenatal women in the study population in the present study, one is a migrant female from some northern part of India.
It was noted in the present study that there is an increase in seropositivity among the study population who have travelled outside Kerala, which implies a higher prevalence in other states, especially northern states.,,
There is also an increase in seropositivity of anti-HEV IgG among those who consumed food from outside where the hygiene is very poor. This could be attributed to more migrant population working in hotels and restaurants, who might have moved from an area with higher prevalence to hepatitis E.
Some of the risk factors have played only a minor role in the present study population. Significant association between risk factors and prevalence could have been brought out by increasing the sample size.
Limitations of the study
Due to resource constraints, confirmatory test like polymerase chain reaction was not performed.
| Conclusion|| |
The low seropositivity among healthy adults shows an increased susceptibility to HEV infection. It implies that there is an immense potential for HEV epidemics to occur in central part of Kerala. Furthermore, since there is an increase in migrants from high-endemic area, screening for HEV in adult population, especially pregnant females, is desirable. Establishment and implementation of preventive strategies in the form of safe drinking water supply, sanitation, increasing awareness, and behaviour change with respect to personal hygiene, especially hand and food hygiene, are to be emphasised.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| Annexure 1|| |
Name: Age/Sex: IP/OP No.:
Duration of settlement:
Education status: Occupation:
Monthly income: <5000/5000–15000/>15000
Source of water: Well tube/well tap/water/pond/other
Treatment of water: Boiled/filtered/other/untreated
Sanitary conditions: Sewage/system/septic tank
Hand washing: Regular/Irregular
: With soap/without soap
Food from outside: Frequent/Infrequent
History of travel outside Kerala: Yes/No
Family history of jaundice: Yes/No
Vaccination for hepatitis A/B: Yes/No
Serology: Immunoglobulin G antibody against hepatitis E virus:
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