Introduction
Hepatitis Delta Virus (HDV) is a small satellite RNA virus classified within delta viruses. In 1977, HDV was first repoted by Dr. Marcus Rizzetto in individuals infected with HBV.1 Hepatitis B virus (HBV) is a global health problem with 248 to 292 million people chronically infected worldwide.2, 3 Although, the exact prevalence of HDV infection cannot be predicted due to absence of standard screening procedures and inaccessibility in some resources limited countries but in a recent analysis, 13% to 14% which corresponds to 62 to 72 million people were found to be infected with HDV worldwide.4 According to World Health Organisation (WHO) 5% of HBsAg carriers worldwide are infected with HDV.5 HDV is a single stranded defective RNA virus which needs Hepatitis B virus (HBV) for completion of its replication cycle inside the host cells. Hepatitis B virus provides HDV with its surface antigen (HBsAg), which HDV needs for transmission between hosts. Though HDV is considered to be imperfect and requires HBV to be human pathogen, HDV is considered to be most severe and rapidly progressive form of chronic hepatitis.4 Infection with HDV and HBV viruses can occur in two ways: it can happen simultaneously, co-infection or HDV can infect people after initial HBV infection, super-infection. 6 HDV infection is associated with higher rates of fulminant hepatitis in acute cases and cirrhosis and hepatocellular carcinoma in chronic infections than HBV alone and persisting HDV replication is considered the most important predictor of mortality. 7 The transmission routes of HDV are similar to those of HBV and researchers have shown that very little inoculums are sufficient for transmission. 8 These routes include blood transfusion, intravenous drug abuse, sexual contact and nosocomial infection. Anti-delta antibodies appear in the serum during infection and can be detected by enzyme-linked immunosorbent assay(ELISA). 4 Different studies have shown that the geographic distribution of HDV infection is heterogenous and that comprehensive surveys in HBV infected patients should be conducted to determine the risk factors and prevalence of infection. 6
Aims and Objectives
East district has a population of 2,83,583 (India Census, 2011) and approximately on an average 2013 blood donors donate blood annually. However, no major study has been done on Hepatitis D in this region. Routine screening is not done for it. Therefore there is insufficient data on its incidence or prevalence in this part. It is very important for health providers and policy makers to recognize the risk of dual infection with HBV and HDV and design effective preventive program.
The study was carried out in east district of Sikkim with the following objectives:
Material and Methods
The present study was designed for duration of one year from February 2021 to February 2022. The study was done in collaboration with Central Referral Hospital, Tadong and STNM Hospital (Sir Thutop Namgyal Memorial Hospital), Gangtok in the East district of Sikkim. A total of 64 samples positive for HBsAg in the routine blood donors reporting to the blood bank and the hospital admitted patients were collected in clot vial. Informed consent was obtained from both the donors and hospital patients who were Hepatitis B positive. The samples were centrifuged for 5 mins at 3000 rpm and the serum was collected. The serum samples were screened for the presence of anti-HDV IgG antibody using Enzyme Linked Immunosorbent Assay [CAT NO CSB-E04809h Human hepatitis D virus (HDV) antibody (IgG) ELISA Kit]. The cut off value as per CUSABIO user manual guide calculation was 0.1417. The datas were entered and analysed using SPSS version 2.0. Institutional Ethical clearance was taken from the Institute for the study.
Results
A total of 64 samples positive for HBsAg were analysed with a M:F ratio of 1.46. The Hepatitis B positive samples were predominant in the 20-40 years age (57.8%). [Table 1; Figure 1 a] The adolescent and the adult population were most vulnerable. Majority of the patients were Hindu and were from the Nepali community (40.6%), as they form the predominant population in East Sikkim.[Table 2; Figure 1 (b)&c] Only one female patient (1.6%) out of 64 was positive for Hepatitis B and Hepatitis D co-infection.[Table 2; d] The female patient had a history of high risk behavior. Treatment has been initiated and the patient is under follow up.
Table 1
Age group (years) and gender wise ditribution
|
|
M |
F |
0 to 10 |
11 to 20 |
21 to 30 |
31 to 40 |
41 to 50 |
≥ 51 |
|
Frequency |
38 |
26 |
0 |
4 |
19 |
18 |
07 |
16 |
|
Percent (%) |
59.4 |
40.6 |
0 |
6.25 |
29.68 |
28.12 |
10.9 |
25 |
|
Total |
64 |
|||||||
Table 2
Summary chart
Discussion
HDV is dependent on HBV and the epidemiology of HDV is similar to HBV with exceptions. The prevalence of HBV has declined globally due to vaccination and increasing awareness. It is estimated that about 5% of HBsAg carriers worldwide are infected with HDV. 5 In our study, positive rate for Hepatitis B & D coinfection was 1.6%. This is a first case study reported from Sikkim on HBV and HDV coinfection. Our results are higher than the postulated global prevalence of 0.82%. 9 Though several studies have been done in India to estimate the prevalence of HDV infection but there are no data on national survey. In Northern India, the prevalence of hepatitis D in HBsAg-positive individuals from New Delhi was reported to be 10.6% in 2005. 10 In Kolkata, the prevalence was found to be 3.3% in 1998. 11 In Mumbai, according to a study done in 1992, the HDV prevalence was 37.46% in HBsAg-positive patients. 12 In Southern India, low HDV prevalence in patients undergoing hemodialysis was reported in a study published in 1991. 13 However, our results are lower than the above studies. In a study done by Attaran MS et al in Iran 2% of them were positive for anti-HDV.14 In a study by Ajayi BB et al in nort-east Nigeria in 2019, the prevalence of HDV co-infection was 3.3 %. 4 Similarly, a study was done by Nahed IM Gomaa, et al in Ismailia, Egypt anti-HDV antibodies were detected in 8 (4.7%) individuals aged from 29-43 years. 15 In South Asia, most of the countries are poor, densely populated and lack good health infrastructure, conditions that are favorable for the spread of hepatitis B and other related infections. 16 A recently conducted study showed a very high HDV prevalence of 58.6% in HBsAg-positive patients who visited liver clinics in Karachi and Jacobabad.17 A study done by Luna Adhikari et al in 2010, showed the seropositivity of HBsAg to be 0.78 18
Conclusion
This is the first study on the prevalence of Hepatitis B and D coinfection in blood donors and hospital patients in East District of Sikkim. A larger epidemiological study needs to be performed to know the true prevalence rates of these infections in Sikkim and North-eastern part of India. Population is at risk of acquiring these infections and therefore necessary steps must be taken to prevent the transmission of these viruses. Safe blood transfusion is a pre-requisite for the individual and the community as well. Mass screening, routine HBV immunization and awareness regarding the spread of the infection must be created in the community. Hence, it is very important for health providers and policy makers to recognize the risk of dual infection with HBV and HDV and design effective preventive program.
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