**4. Discussion**

HBV infection is an important global problem that places a continuously increasing burden on developing countries. As the HBV genotype can be classified into different genotypes, the classification has to be cost-effective and clinically relevant [19]. Research on the relationship between HBV genotypes, their pathogenicity in chronic liver disease, including hepatocellular carcinoma, and their therapy are of grea<sup>t</sup> interest, as this allows for understanding the spread and risk of HBV infection around the world [10]. On the other hand, HBV infection is a major health problem in the Middle East. The majority of the countries in the region have an intermediate or high endemicity of HBV infection [20]. Despite the low prevalence of HBV in Bahrain, it is important to investigate the frequency of HBV genotypes and its association with various sociodemographic factors, hepatic biomarkers, and mode of transmission, which is essential for fine tuning the control of the disease.

According to a study by Janahi (2014), completed on 877,892 individuals, Bahrain has low HBV endemicity for the period (2000–2010). The prevalence of hepatitis B virus infection in Bahrain was found to be 0.58% [21]. This study reports for the first time in Bahrain, the correlation of HBV genotypes frequency with the demographic characteristics and hepatic biomarker. The results showed that there were no significant differences of genotype frequency in relation to the demographic characteristics as well as hepatic biomarkers. Out of the 82 screened patients in this study, 58.5% were male, while the remaining 41.5% were females. There was a significant increased risk of HBV infection in male as compared to females (Table 1). 53.7% of HBV positive patients had Bahraini nationality, while the remaining 46.3% belonged to other eleven nationalities, such as Pakistan, Sudan, Egypt, Yamen, Syria, Kuwait, Bangladesh, India, Ethiopia, Indonesia, and Philippines, which are known to be highly endemic for HBV. Relationship between genotype and age-group indicates that HBV prevails 4.9% in <21 years, 28% in 21–30 years, 25.6% in 31–40 years, 13.4% in 41–50 years, 15.9% in 51–60 years, and 12.2% in >61 years. age groups.

The frequency of mode of transmission was highly unknown (59.8%), followed by blood/blood products (19.5%), sexual contact (7.3%), vertical transmission (7.3%), and finally organ transplant (3.7%). HBV and HCV have common modes of transmission; therefore, their coinfection is quite frequent. This particularly occurs in areas where the two viruses are endemic and among subjects with high risk of parental infection [22]. According to a study that was conducted in Bahrain, dental procedures and surgical operations account for 37.2% and 35.6%, respectively, of the HBV transmission routes. Followed by the blood transfusion (24.6%), the sexual contact and intervenors drug abuse were the least possible routes of transmission [21]. There was some significant difference in the HBV genotype prevalence with respect to some investigated variables. For example, the frequency of HBV genotype is more related to males and the risk of HBV infection increased with older age.

The dominant genotype in our study was genotype D with 61% frequency, which is similar to some countries in the Middle East, like Saudi Arabia (81%) [23], UAE (79.5%) [24], Iran, and Jordan (≈100%) [25,26]. The dominance of this genotype might be attributed to different factors, such as the presence of high number of workers from countries that are known to have dominant D genotype, such as India, Pakistan, Yemen, Syria, and Bangladesh. These infected workers are a principal source for the transmission of hepatitis B. As most of them belong to highly endemic countries with low educational and socio-economical backgrounds, they positively contribute to the transmission of the disease. Living in small houses and having unhygienic behaviors (such as sharing same razors and toothbrushes) put such workers at high risk of contracting HBV. A poor hygiene system in hospitals of such countries is known as a high-risk factor for HBV transmission, as the same syringe is used for vaccination of different people [27].

The quasi-species nature of HBV infection indicates that the variation and evolution of Hepatitis B virus has been influenced by the recombination between genotypes. Hence, a high prevalence of more than one dominant genotype in a certain region is common [16,28]. It is documented that mixed infection with different HBV genotypes is not uncommon and it is of grea<sup>t</sup> virological and clinical interest. For example, a study done by Chen et al. (2004) showed that the prevalence of mixed HBV genotype infection was 16.3% for HBsAg positive and 34.4% in occult HBV-infected intravenous drug users [29].

HBV is non-cytopathic virus, which highlights the complex and important interaction between the virus and host in causing HBV-related liver disease. Bilirubin, Direct Bilirubin, ALT, and AST are the most common liver enzymes that are measured to investigate the condition of liver due to HBV or HCV infection [30]. Elevated ALT levels, elevated AST level, elevated serum bilirubin, and decreased serum albumin might be indicative of advanced liver disease and even cirrhosis [31]. In our study, there was no significant association between HBV prevalence and liver function test. However, each genotype showed variation depending on the mean and standard deviation of the liver function test associated with that genotype. The most dominant genotype in the present study, genotype D showed high levels of ALT and GGT above the normal range. This might be indicative of acute hepatitis. Genotype A and mixed genotypes B/D showed higher than the normal maximum level for ALT, AST, and GGT; mixed genotypes A/D showed higher than the normal maximum level for Bilirubin, ALT, AST, and GGT; genotype B showed higher than the normal maximum level for ALT and GGT; genotype D showed higher than the normal maximum level for ALT and GGT; and, genotype E showed higher than the normal maximum level for AST and ALT. Genotype C and undetermined genotypes showed normal liver function enzymes levels. It is also reported that persistently elevated liver enzymes levels in an asymptomatic hepatitis B patient is associated with high infectivity [32].

This study, as any study, has some limitations. Firstly, 82 individuals only were screened, which is a relatively small sample and it may not represent an accurate picture of HBV prevalence at the population level. Secondly, no cases from other governmental and private health facilities were included in our study which may contribute to lower prevalence. However, according to the latest data that were obtained from the Public Health Directorate, Ministry of Health, the number of HBV positive patients at population level was 527, so our sample 82 represents approximately 16% of the

total HBV patients in Bahrain. Thirdly, some of the obtained data from patients were based on patient self-reporting of risk factors, which is subject to social desirability bias.

Finally, this study showed that the overall HBV prevalence among males' patients to be 58.5%, while it was 41.5% among females. The dominant HBV genotype in Bahrain was genotype D (61%), which was associated with higher than the normal maximum level of ALT and GGT.
