Prevalence and Risk Factors for Hepatitis Delta Virus Transmission among HBsAg Positive Blood Donors in Brazzaville, Congo

Background: Hepatitis D virus (HDV) is a defective virus that requires the presence of hepatitis B virus (HBV) for replication. It is a major cause of severe acute and chronic hepatitis B. The objective of this study was to determine the prevalence and risk factors of HDV in blood donors. Methods: This was a descriptive, cross-sectional study involving HBsAg-positive blood donors covering the period from July to December 2020. Testing for HDV RNA was performed by conventional two-step RT-PCR. Data were analysed using SPSS version 22 software. Result: Of 113 HBsAg positive samples included in the study 22 or 19.5% were HDV positive. The prevalence of HDV was higher in the age group 31 - 45 years (45.5%), in male donors (71.4%) and in donors with secondary education (50.0%). Furthermore, 55.4% belonged to the family donor category. A significant statistical difference was observed between HDV infection, tattoos, piercings and multiple sexual partners. Conclusion: This study shows a high prevalence of HDV among blood donors in Brazzaville.


Introduction
Hepatitis, an inflammation of the liver, can be caused by various viruses such as others are transmitted exclusively through blood and contaminated blood products [1]. Hepatitis D virus (HDV) is a small, defective RNA virus that requires hepatitis B virus (HBV) to complete its replication cycle within host cells [2], and infects only HBV surface antigen (HBsAg) positive individuals [3]. HDV infection is therefore the result of HBV and HDV co-infection or HDV superinfection of chronically HBV infected patients. In combination with HBV, HDV causes much more severe disease than HBV alone [4]. HDV is currently well known to cause a range of acute and chronic liver diseases [5]. Individuals with HBV-HDV co-infection may have more severe acute disease and be at greater risk of fulminant hepatitis, cirrhosis and hepatocellular carcinoma (HCC) than those with HBV infection alone [6] [7]. As with HBV, transmission of HDV occurs through sexual intercourse, blood or horizontal transmission [8]. It is estimated that 62 to 72 million people worldwide may be living with HDV [9]. HDV infection has a worldwide distribution, but its frequency varies greatly throughout different geographic regions. It is highly endemic in the Middle East, in the Mediterranean area, in the Amazonian region, and in several African countries [10]. In Africa, a quarter of the estimated 65 million chronic HBV carriers are suspected of being HDV carriers [11]. In the Republic of Congo, the prevalence of HDV is 12.2% in the general population [12]. Despite this prevalence, no study on the prevalence of HDV has been conducted among blood donors in Brazzaville. It is in this context that we conducted this study to determine the prevalence and risk factors of HDV transmission among blood donors in Brazzaville.  The inclusion criteria were: all HBsAg-positive blood donors aged 18 -60 years were included in the study, having agreed to participate in the study after informed consent and signing a voluntary commitment form.

Sample Collection
Plasma samples from 113 blood donors tested positive for HBsAg by ELISA (Monolisa™ HBsAg Ultra, Bio-Rad, Marne-La-Coquette, France) were aliquoted into cryotubes and stored at −40˚C.

Biological Screening
The presence of HDV RNA was detected in HBsAg-positive plasma samples by  [12] in a TECHNE TC-312 thermal cycler. The amplified PCR products were subjected to electrophoresis on a 2% agarose gel.

Statistical Analysis
Statistical analysis of the data was carried out using SPSS version 22 software.
The Chi 2 test and Fisher's exact test were used to compare proportions in order to establish the different associations between the parameters studied. Differences were considered significant at a p-value < 0.05.

Discussion
Viral hepatitis delta remains one of the major public health problems in the world. It is estimated that 62 to 72 million people are living with HDV worldwide [9].   [10] in Pakistan who reported a mean age of 32.7 ± 14.7 and Alizadeh et al. [22] in Iran who observed a mean age of 36.9 ± 12.6. This predominance of younger age could be explained by the fact that HBV infection, which is associated with HDV, is chronic and much more common in early childhood. However, age is unlikely to be a factor influencing the results, as our study focused on the blood found a predominance of infection in married individuals [13]. Intra-familial transmission has been proven by Niro et al. in Italy [23]. Tattoos and piercings were also found to be important risk factors for HDV infection, which probably explains the rather high prevalence of infection among young people. Similar results were reported by Gheorghe et al. [14] in Romania. Many studies indicate that sexual transmission is a more important risk factor [24].

Conclusion
In conclusion, the prevalence of HDV among blood donors in Brazzaville is high and represents a major public health problem with an enormous burden in terms of health expenditure. It is necessary to continue studies on a large sample size.

Funding
This work was supported and financed by The National Center of Blood Transfusion Congo (CNTS).

Availability of Data and Materials
The datasets used and/or analysed in this study are available from the corresponding author upon reasonable request.