| Abstract|| |
INTRODUCTION: Asymptomatic hepatitis E virus (HEV) infections have been found in blood donors. Posttransfusion hepatitis E has been reported and raises concern due to cases of HEV-related mortality in patients with underlying cirrhosis or immunocompromised patients. This study aimed to determine the seroprevalence of HEV-associated sociodemographic parameters, awareness about feco-oral transmitted diseases among healthy blood donors attending a tertiary care teaching hospital blood center.
MATERIALS AND METHODS: This was a cross-sectional study done for 1 year from January 2019 to January 2020. Our study included a sample size of 920 blood donors attending for donation at a single center. All the samples were tested using HEV IgM kit with the antigen used for coating were four synthetic peptides with conservative epitopes of ORF2 and ORF3 in genotypes 1, 2, 3, and 4. An open-ended questionnaire regarding awareness of the feco-oral transmission of diseases was administered; data regarding clinical, epidemiological, and demographic characteristics were collected from the donors by a structured data collection proforma. The responses were recorded.
RESULTS: Our study results showed a seroprevalence of 1.41%. All the reactive donors were asymptomatic during our routine screening procedures. Most of the donors (457 donors), i.e., 49.7%, belonged to the lower middle class; the mean age of the study population was 28.6 years (standard deviation 8.9).
CONCLUSION: This study reflects the burden of HEV in the local population, and this result can be considered a preliminary step in quantifying the risk of transfusion-transmitted HEV. Cost-effectiveness in implementing HEV screening as a part of routine TTI screening to be considered.
Keywords: Blood donors, feco-oral transmission, hepatitis E virus, Puducherry
|How to cite this URL:|
Pichai S, Basavarajegowda A, Dhodapkar R. Hepatitis E virus seroprevalence and awareness about feco-oral transmission in blood donors at a single center in Puducherry. Asian J Transfus Sci [Epub ahead of print] [cited 2023 Mar 24]. Available from: https://www.ajts.org/preprintarticle.asp?id=345984
| Introduction|| |
Asymptomatic hepatitis E virus (HEV) infections have been found in blood donors. The first case of transfusion-transmitted HEV (TT HEV) was reported from Hokkaido, Japan. Following that, TT HEV was reported from various countries. Initially, it was thought HEV infection was self-limiting. It gained importance when cases of HEV-related mortality in patients with underlying cirrhosis, immunocompromised patients such as transplant recipients, HIV patients, and patients on chemotherapy have been reported., Currently, 75% of blood or blood components are given to immunosuppressed patients in countries like the UK.
In a study among healthy blood donors in Western, India seroprevalence was 4.78%. European studies showed HEV IgG prevalence of 52% in a hyperendemic area in the South of France, 27% in Dutch blood donors, 6.8% in German blood donors.,, Studies from the United Kingdom, Japan, and France showed HEV RNA in plasma donors. Many prospective studies have been done in European countries, and countries like Japan have implemented universal screening of HEV to provide safe blood to patients.,,,
Screening of donor blood for HEV is not mandatory in India. Indian Blood banks depend only on the verbal questionnaire to rule out the risk of transfusion–transmitted HEV. Around 11 million units of blood are collected in India every year. There is an increased risk of transmission of infection through all the blood components, especially to the immune-compromised individuals and patients who require multiple transfusions. Therefore, it is essential to study the prevalence of HEV among healthy blood donors.
The main aim of our study was to determine the seroprevalence of HEV in healthy blood donors attending our blood center and to study associated sociodemographic parameters, awareness about feco-oral transmitted diseases. There are no studies available in the literature on HEV prevalence from Southern India. Most Western studies have shown a significant correlation between HEV RNA positivity and IgM positivity, and most Indian studies used IgG assays. In the current study, we studied the prevalence using IgM assay. IgM positivity shows recent infection in donors, and it is a better assay as asymptomatic viremic donors are the source of infection by transfusion.
| Materials and Methods|| |
Study setting and population
This was a cross-sectional study conducted in the Blood Centre of tertiary level care teaching hospital in Puducherry for 1 year from January 2019 to January 2020 on the blood donors attending for donation. All the donors were selected based on the prevailing national guidelines and departmental Standard Operating Procedure.
Sample size and sampling technique
Assuming a prevalence of 2% with a 95% confidence level and relative precision of 50%, the sample size was calculated to be 752 using Daniel's formula. Considering 10% samples for wastage and standardization of kits, the total sample size was calculated to be a minimum of 828. The first three donors who donated were chosen daily for 5 days from Monday to Friday. Insufficient samples or those which lysed during storage were excluded from the study.
Data regarding clinical, epidemiological, and demographic characteristics were collected from the donors by a structured data collection proforma after getting informed consent. An open-ended questionnaire regarding awareness of the feco-oral transmission of diseases was administered, and the responses were recorded. After completing regular testing, the 5 ml venous blood sample collected in a clot activator tube for routine TTI testing in the blood center was utilized for the assay. Samples were centrifuged at 3000 rpm for 3 mins for separating serum. Then, the separated serum was aliquoted into small vials and kept in deep freezers at −30°.
Hepatitis E virus IgM assay
The kit used for the testing procedure was Dia.Pro HEV IgM kit (Diagnostic Bioprobes Srl, Milano, Italy). The antigen used for coating is four synthetic peptides with conservative epitopes of ORF2 and ORF3 in genotypes 1, 2, 3, and 4. The lot number of the kit was 1018. All the tests were performed as per the manufacturer's instructions in the kit. Samples with absorbance values equal to or greater than the cut-off value were considered reactive with appropriate controls from the kits.
Data collection and statistical analysis
Data regarding clinical, epidemiological, and demographic characteristics, Assay results, and the questionnaire responses were entered along with other details in the Microsoft Excel sheet and analyzed. The statistical analyses were performed using SPSS for Windows version 20 (SPSS IBM Corp. Ltd., Armonk, NY, USA). All the categorical variables such as gender, blood group, religion were expressed as frequencies and percentages. Continuous variables such as age were expressed as mean with standard deviation.
Ethical clearance was obtained from the Institutional Ethics Committee. Before enrolling, written informed consent was obtained from all participants after explaining the study verbally and by a participant information sheet in both English and local language. No extra blood sample was collected for the purpose of the study.
| Results|| |
The mean age of the study population was 27 years. The range of participants was from 18 to 62 years. A total of 13 samples were found to be reactive. The prevalence of HEV was found to be 1.41% (95% confidence interval [CI]: 0.75%–2.40%). The sociodemographic characters of the study population are summarized in [Table 1]. The source water was significant, with nine donors using a public tap as a source of water supply (χ2 [2, n = 920] = 14.17, P < 0.001). Open drain and defecation were noted in 9 participants against four amongst those who used soakage pit; however, it was not statistically significant (χ2 [1, n = 920] = 2.38, P = 0.12). There was no statistically significant association of the seropositivity with any of the other sociodemographic characteristics studied among the population.
The Kuppuswamy socioeconomic status (SES) classification includes three parameters: Occupation, Education of the Head of the family, and total monthly income. The total score of Kuppuswamy SES ranges from 3 to 29. The grading of the socioeconomic class is based on these scores. Most of the donors (457 donors), i.e., 49.7%, belonged to the lower middle class, followed by the upper-middle-class (227 donors-24.7%).
The blood group distribution, TTI status of the donors are summarized in [Table 2]. None of the donors was positive for syphilis or malaria. None of the seropositive donors for HEV had coexisting seropositivity for either HIV, HBV, or HCV.
The profile donors who turned out to be positive for HEV IgM are summarized in [Table 3]. Less than 10% of the participants and the seropositive donors reported people with gastrointestinal diseases in the family. Two of the HEV-positive donors had a family history of jaundice. Among the reactive donors, 69.2% of the donors belonged to 18–30 years. Among the reactive donors, 53.4% of donors belonged to the lower-middle socioeconomic class. One of the donors who were positive for HEV had a pregnant woman in his family.
The knowledge about feco-oral hygiene among donors was assessed and showed that about three-fourths believed that feco-orally transmitted diseases could be prevented. The most common response (about one-fourth) for what they felt was the reason for the occurrence of these diseases was consuming polluted water, which can be prevented by avoiding water pollution/stagnation. The responses for the same are compiled in [Table 4].
|Table 4: Responses to knowledge regarding feco-oral disease transmission among the study participants|
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| Discussion|| |
In our study, out of 920 samples tested, a total of 13 samples were found to be reactive with a prevalence of 1.41% (95% CI: 0.75%–2.40%). The seroprevalence of HEV ranges from 1% to 52% across the world.
Of the positives, seven donors were replacement donors (53.8%), and six were voluntary donors (46.2%). In general, all TTIs are more common in replacement donors than voluntary donors. Replacement donors do not reveal their medical issues and high-risk behavior often, which may be the reason for the increased prevalence. In our study, we were not able to find any correlation between both the population.
The awareness about fecooral transmission of diseases was fair in the studied population. The noncommittal response was seen in about 20% of the participants. Eating outside food, drinking water from a polluted source, lack of personal hygiene were mentioned as to why they occur, and handwashing, maintenance/requirement for clean drinking water were mentioned as steps to prevent them in future.
The seroprevalence of HEV can be detected by Anti HEV IgM and Anti HEV IgG antibodies. Anti-HEV IgM is the marker for acute infection. The sensitivity of these assays is 97% for immunocompetent and 80%–85% immunocompromised, and specificity was >99.5%. Detection and quantification of Viral RNA are the gold standard for detecting active infection. The seroprevalence varies between and within developed and developing countries. The mode of transmission in Western countries is via infected food or locally acquired infected zoonosis. The mode of transmission in developing countries is through parenteral, feco oral, and perinatal.
The results of HEV prevalence studied by IgM assays are summarized in [Table 5]. This result is in concordance with few results in some studies from Europe by Mansuy et al. and Guo et al.,, Nevertheless, compared to few other studies by Gajjar et al. and Shethwala et al. in India, this prevalence is lesser., The reasons behind these variations in seroprevalence may be due to endemicity of the infection, Genotype of HEV, Difference in the screening strategies, Difference in NAT strategies adopted, and Sample size. Most of the studies done in European and Western countries included testing of IgG and IgM, RNA quantification followed by phylogenetical analysis. Most of the studies done in India estimated the seroprevalence either by IgG and IgM.
|Table 5: Comparison of hepatitis E virus prevalence by IgM with other studies|
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Between 2015 and 2016 in Italy, Spada et al. tested a total of 10,011 samples. The IgG prevalence was found to be 8.7%. The IgM prevalence was found in 46 donors (0.4%; CI, 0.34–0.61). This was found to be lesser when compared to our study. They mentioned that Italy has the lowest seroprevalence when compared to other European countries. The possible reason told was the high anti-HEV titer or the low infectious dose.
A study was done in Egypt from January 2017 to 2018 by Al-kasabi and Al-Kasaby and Zaki. This study included a sample size of 200. The seroprevalence of HEV IgM was found to be 5%. This seroprevalence is higher when compared to our study—the reason they attribute to the higher seroprevalence in the occupation and residence of the donors. Most of the donors in their study belonged to a rural area, and their main occupation was agriculture. However, the sample size was also notably small in them.
In the pilot study done by Gajjar et al., the seroprevalence was 4.78%. This study utilized the same kit as our study. This age distribution of donors was found to be similar to our study. They showed a significant correlation between the rise in alanine transaminase (ALT) levels (19 donors out of 22) and IgM positivity. The mean value of ALT was 26.06 IU/L. In our study, ALT levels were not done. ALT levels even if it is done, asymptomatic IgM-positive donors with normal ALT levels can still transmit infection. In this aspect, IgM can be a still better marker when compared to ALT. The seroprevalence of 4.78% is higher when compared to our study. Most of our study participants (97.4%) had proper toilets and sanitation facilities. This may be one of the reasons for low seroprevalence.
A study done by Tripathy et al. on 2447 donors showed an HEV IgM and HEV IgG seroprevalence of 0.2% and 17.7%, respectively. This seroprevalence was lesser when compared to our study. The mean age of reactive donors was found to be 28 years.
A study by Shethwala et al. from November 2014 to December 2017 compared three different assays. Their sample size included 1280 males and 65 voluntary female donors. The mean age group is 32.4 years. They used three different assays for detecting the seroprevalence of IgG and reported Dia. Pro to be less sensitive, but they did not compare it against the gold standard.
The rate of asymptomatic HEV infections raises concerns about infection transmission through blood. Posttransfusion hepatitis E has been reported from various countries. The implication is that transmission of HEV associated with transfusion is undiagnosed because donated blood is not tested for HEV and most resulting infections are asymptomatic. The issue of HEV and blood safety hence warrants further studies.
Cost per Dia.Pro HEV kit was 9600 rupees, and 92 samples can be run in one kit. The cost of the test and other consumables used will cost around 150 rupees per assay.
The Strength of the study is that our study used HEV-IgM assay to detect seroprevalence compared to most of the Indian studies that used HEV IgG. Donor knowledge about the feco oral transmission of diseases and their associated disease was also assessed in this study.
The limitations of the study are that the confirmation of infection by HEV RNA/genotyping was not done, or follow-up/look back was done for reactive samples. Our study had a very skewed female population, so gender distribution could not be established.
| Conclusion|| |
It may be prudent to estimate what proportion of this positivity leads to infection that can be transmitted. The cost-effectiveness of implementing these tests will also need to be evaluated. Mandatory screening of blood donors for infection would be expensive. Screening should only be implemented after evaluating the risk of the infection posed by apparently healthy blood donors.
The study was funded by our Institute Intramural Research Fund.
Financial support and sponsorship
This study was intramurally funded by JIPMER, Pondicherry.
Conflicts of interest
There are no conflicts of interest.
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Department of Transfusion Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]