Hepatitis D in Patients Infected with Hepatitis B Virus in Cotonou: Characteristics and Risk Factors

Introduction: Hepatitis D virus (HDV) is a satellite virus of hepatitis B virus (HBV). The purpose of this work was to describe the epidemiological, clinical and biological characteristics of HBV/HDV co-infection and the factors associated with this co-infection in Cotonou. Methods: This was a cross-sectional, descriptive study with prospective data collection. It took place from June to October 2016 at CNHU/HKM and the Atinkanmey Polyclinic in Cotonou. Subjects over 15 years of age with HBsAg and untreated for hepatitis were included consecutively. Sociodemographic, clinical and biological characteristics were collected for each patient using only a standardized questionnaire. Then, a blood sample was taken for the determination of anti-HDV antibodies as well as the viral load of HBV. Results: A total of 156 subjects were included, predominantly male (sex-ratio = 2), and of median age 36 years. The majority were monogamous married (50%) or single (41.7%), and were from south of Benin (84.6%). Most subjects were asymptomatic (49.4%). The prevalence of total HDV antibodies was 3.9% (6/156). In subjects with total HDV antibodies, the prevalence of HDV IgM was 33.3%. Origin in northern Benin appears to be a risk factor for HDV infection (p = 0.042). Similarly, married subjects were statistically more infected with HDV than unmarried subjects (p = 0.002). Conclusion: The prevalence of HDV infection varies according to the origin of the patients and their marital status.


Introduction
Hepatitis B virus (HBV) infection is a global public health problem with nearly 257 million chronic carriers worldwide [1]. Sub-Saharan Africa is an area of high hepatitis B endemicity with an HBV prevalence of more than 8% [2]. It is a major cause of morbidity and mortality due to its complications with cirrhosis and hepatocellular carcinoma (HCC). The hepatitis delta virus (HDV) is a satellite virus of HBV [3]. Compared to hepatitis B alone, HDV infection results in much more severe acute or chronic hepatitis and faster progression to cirrhosis and HCC [4] [5].
VHD is an enveloped virus, generally spherical in shape and 36 -43 nm in diameter. The viral envelope, consisting of the HBV envelope, surrounds a nucleocapsid made of an RNA molecule and a unique structural protein, the hepatitis delta antigen (HD Ag), which is essential for the assembly and propagation of HDV.
There are two isoforms of HD Ag, the short form (HD-S Ag) and the long form (HD-L Ag) [6] [7]. Because of its characteristics that distinguish it from all viruses in the animal kingdom, the International Committee on Viral Taxonomy has proposed to classify HDV in the genus delta virus [8]. Eight genotypes of HDV (1 to 8), variously distributed, have been identified, of which genotypes 5 to 8 are predominant in West and Central Africa. HDV shares the same modes of transmission with HBV. These are either parenteral (post-transfusion or intravenous drug use contaminations), sexual (heterosexual or homosexual), or maternal-fetal (vertical or more often horizontal by perinatal superinfection of a new-born baby carrying the HBs antigen) [9] [10]. In Africa, people are generally infected during childhood and adolescence by vertical transmission from mother to child or by horizontal transmission through tattoos, acupuncture and ritual scarifications [11].
Despite missing data in many endemic regions of the world for HBV, the number of people infected with HDV is estimated at 15 to 20 million [12] according to the World Health Organization (WHO). In Benin, data on HDV infection are scarce. The only study published to our knowledge was on pregnant women with HBsAg at Saint Jean de Dieu Hospital in Tanguiéta in 2014. The prevalence of HDV infection in this population was estimated at 11.4% [13].
However, this study only included a limited sample of subjects (44 pregnant women) with HBsAg.
The objective of this study was to describe the epidemiological, clinical and biological characteristics of HBV/HDV co-infection and the factors associated with this co-infection in Cotonou.

Methods
This was a descriptive and analytical cross-sectional study with prospective col-  used, and the difference was considered significant for a p < 0.05.
The study was not submitted to an ethics committee. But the verbal consent of the patients included was obtained, and the data collected and treated in strict confidentiality.

Results
One hundred and fifty-six subjects met the inclusion criteria. The prevalence of total HDV antibodies was 3.9% (6/156). In subjects with total HDV antibodies, the prevalence of HDV IgM was 33.3% (2/6).
For the remainder of this article, we will distinguish two types of subjects: subjects infected with HBV but not with HDV and who will be called HDV− and Open Journal of Gastroenterology subjects infected with HBV and HDV and who will be called HDV+.   (Table 3).
Biologically, the median viral load in HDV+ subjects was 54.5 IU/mL, lower than that of 582 IU/mL in HDV subjects, with a statistically significant difference (p = 0.02; Table 3). On the other hand, the Ag HBe status, and the transaminase level are not statistically different between HDV+ versus HDV−, according to Table 3.
In the study population, 1.3% were HCV-HBV co-infected (2/151) and 0.7% were HIV-HBV co-infected (1/148). There were no cases of HBV-HCV-HIV co-infection. Among subjects infected with HDV, no cases of HIV co-infection or HCV co-infection were found and no significant differences between the two groups HDV+ and HDV− for co-infections with HIV and HCV were observed (p > 0.999) ( Table 3).

Discussion
It appears from this work that the prevalence of anti-HDV antibodies was 3.9% A. R. Kpossou et al. Open Journal of Gastroenterology in patients followed for hepatitis B in Cotonou. This prevalence is higher than the 0.23% found in 2015 in Slovenia [14]. It is comparable to the prevalence of 3.5% reported in 2011 in France [5]. It is also comparable to the 3.38% found in 2015 in Burkina Faso by Sawadogo et al. [15]. However, it is lower than that previously found by De Paschale et al. [13] [23] in blood donors with HBsAg. These authors reported that subjects who were married more than once were more infected than subjects who were married once and those who were never married (p = 0.04). In this study, information on the number of times the subject was married was not collected. The fact that married subjects are more affected by HDV suggests an important role for sexual transmission of this virus. It should also be noted that married subjects are generally older than unmarried subjects and therefore have a higher cumulative risk of HDV infection than unmarried subjects. The fact that subjects from the North are more affected in this work reinforces the higher prevalence of HDV in northern Benin. Mansour

et al. in
Mauritania noted that subjects living in the desert were significantly more affected than those in other regions [17] [23]. The association between HDVs and northern origin could be justified by cultural practices such as scarifications, FGC and serial non-medicated circumcision that are reportedly more prevalent in the North than in the southern part of the country [24]. These data on HDV should be compared with the higher prevalence of HBV in northern Benin. Indeed, Kodjoh et al. had found in 2013 that the prevalence of hepatitis B was higher in the North than in the South of Benin with the highest prevalence in the departments of Atacora-Donga which was 20.15% compared to 9.08% in the Atlantic-Littoral departments where Cotonou is located [25]. Open Journal of Gastroenterology Clinically, in the majority of HDV+ cases, the disease was revealed by clinical manifestations (digestive disorders in four cases, and asthenia in one case) unlike HDV− subjects in whom HBV was discovered predominantly through voluntary screening. These results are in line with the literature because chronic HDV infection is very rapidly progressive and leads to cirrhosis in 80% of cases [26]. reported that all VHD+ subjects were HBe Ag negative [20]. The HBV viral load was significantly lower in VHD+ subjects than in VHD− subjects (p = 0.02).
These results are similar to those of Liao et al. in China [22] and Ghamari et al.
in Iran in 2012 who reported low HBV viral loads in positive or even undetectable anti-HDV antibodies subjects for some [20]. Lunel-Fabiani et al. found that 81.6% of subjects with positive anti-HDV antibodies had an HBV viral load < 2000 IU/mL, but found no difference between the medians of HBV viral load in logarithm (log) of VHD+ and VHD− [21] subjects. It is indeed well known that VHD inactivates the replication of VHB [28].
The small number of VHD+ subjects found may have decreased the power of the study, particularly in the search for risk factors. Indeed, the sample size was calculated on the basis of the study carried out in Tanguiéta [13] where a higher prevalence had been observed. However, the present study is, to our knowledge, the first study that really allows us to assess the extent of HDV infection in HBV-infected subjects in Cotonou. A larger study covering all departments of the country will make it possible to specify this prevalence at the national level and to refine the risk factors studied.

Conclusion
This study shows that only 3.9% of HBV-infected subjects also had an HDV in-