This is a cross-sectional retrospective and descriptive study carried out at the Katele Reference Center in Moba from 2014 to 2016, i.e. three years. The Katele Reference Health Center (RHC) is located in Moba-Port, in the health area of Moba-Port (population 2017: 25,266 inhabitants), mainly on the shores of Tanganyika Lake, in the health zone of Moba, Province of Tanganyika in the DRC. It covers an estimated population of more than 60 thousand inhabitants, mainly from health areas along Tanganyika Lake (Regezza, Mulunguzi, Kansenge, Liombe, etc.) over a distance of more than 70 km. The main diseases encountered are, in order of importance: malaria, acute respiratory infections, simple diarrhea, dysentery (especially in artisanal mineral extraction areas), measles, cholera (seasonal pattern) and sexually transmitted infections (STI).

The territory of Moba has an area of 24,500 km² and 609,406 inhabitants, i.e. a density of 24.9 inhabitants/km² [29] . The ethnic populations are predominantly Tabwa (over 80%), Bemba and Luba. There are also other tribes from the DRC and neighboring countries (Tanzania and Zambia). The main activities include agriculture and fisheries. This fishery on Tanganyika Lake attracts people from several towns in the DRC and neighboring countries: Kalemie, Mbuji-Mayi, Kananga, Uvira, Bukavu, Lubumbashi, Kolwezi, Pweto and Kirando (Tanzania). This fishery concerns the species specific to Tanganyika Lake, namely Stolothrissa tanganikae (locally called “DAGA”) and Luciolates (locally called “MUKEBUKA”).

Our study population consisted of all blood donors of the period concerned (n = 1145). The age, sex, type of blood donation (family, irregular volunteer circumstantial or paid) and the result of the serological investigation of the HBS Antigen were the desired parameters.

The Australian antigen or HBsAg corresponds to the surface antigen of HBV, discovered accidentally by Blumberg in 1964 [13] . It is currently the most widely used serological marker for the diagnosis of acute and chronic HBV infections (presence of HBS Antigen in serum indicates active, acute or chronic viral hepatitis B) and for the screening of blood donors and organs. The title of circulating HBsAg would reflect the amount of DNA-ccd (covalently closed circular deoxyribonucleic acid) present in the liver [13] . HBSAg is the serological marker appearing 1 to 3 months after the contamination and 2 to 4 weeks before alanine aminotransferases (ALAT) [13] [22] .

In the context of this study series, the Rapid Diagnostic Test Determine^® HBsAg (Abbot, Tokyo, Japan) was used to research for HBsAg according to WHO guidelines [2] [30] . Determine^® HBsAg is an immunochromatographic test for the qualitative detection of hepatitis B surface antigen (HBsAg). The blood sample is deposited on the sample deposition area and migrates to the deposition area of

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the conjugate; it is reconstituted and mixed with the selenium-antibody colloid conjugate Figure 1. This mixture continues to migrate on the solid phase to the immobilized antibodies at the patient window on the test. If HBsAg is present in the sample, it binds to the antibody of the selenium antibody-colloid conjugate and the patient window antibody by forming a red line. If, on the other hand, HBsAg is absent, the selenium antibody-colloid conjugate passes through the patient window without forming a red line. A procedure control bar is included in this assay system to ensure the validity of the assay [13] [29] [31] . The laboratory at the Katele HRC uses a single HVB (Determine^® HBsAg) screening test without confirmation by more sensitive and specific tests such as Enzyme-Linked Immunosorbent Assay (ELISA).

The data collected on a pre-established form were encoded on the Excel table (Microsoft, USA, 2010) before being exported for processing on the Epi Info 7.1 software (CDC, USA, 2012). The results were presented in the form of tables and figures showing observed numbers, frequencies, proportions and parameters of central tendency and dispersion (mean, standard deviation, median as necessary). The association between the variables studied was assessed using the unadjusted Pearson chi-square test. The allowed alpha error was 5% and any value of p ≤ 0.05 was considered significant.

During the period of our study on the prevalence of HBV infection in blood donors, blood donors were found to be young adults aged 18 to 49 years and an average of 30.6 ± 6.9 years. This age corresponds or is close to what some authors [2] [20] [24] [25] [32] [33] [34] [35] [36] had encountered in different countries. At this age of intense physical activity, individuals consider themselves strong and able to give blood as old men, already weakened by the weight of the age. Male individuals were the most registered among blood donors (62.5%). This observation has been preferentially evoked in several studies [1] [5] [14] [20] [22] [24] [25] [28] [37] [38] . For Batina et al. [26] , blood donors were mainly women. The arguments favoring male predominance take into account the cultural habits and certain physiological predispositions of women to be excluded from the category of blood donors. Indeed, on the one hand to give blood, the donor must feel stronger and fit for that responsibility. In Africa, it is the man who is considered to be the strongest and responsible for any situation that threatens the family: therefore it is better able to give blood than the woman. On the other hand, pregnancy and breastfeeding are contraindications to blood donation, which would reduce women’s chances of donating blood. Some authors also mention menstrual blood loss in women [5] [6] . Blood donors were predominantly family donors (83.2%) [5] [25] . This study demonstrates the persistence of paid and fa- mily donors in our environment. These categories of donors have been associated for years and in several regions of the world with the risk of transmission of infectious agents during blood transfusions [12] [15] [24] [25] [26] [28] [32] [33] [38] [39] [40] [41] [42] . We believe that the trust of family members in family blood donation and the poor public mobilization policy in favor of regular blood donations are the basis of this situation [8] . Health authorities and partners involved in blood safety and management should be involved to resolve this situation as in some parts of the world and the Democratic Republic of Congo [27] [28] [33] [43] . Our safety of the blood recipient must not remain only in the embryonic stage dating back to 2001 (rehabilitation and inauguration of the National Center for Blood Transfusion) [44] . Several awareness campaigns and funding of national blood transfusion program (NBTP) activities for voluntary and regular blood donations are therefore necessary.

In Africa, the prevalence of HBV infection is 0.2% to 20% among blood donors [5] [10] . The cumulative seroprevalence of HBV infection (HBsAg) during the three years of study was 3.9%. It is close to the results encountered by Kabinda [33] 4.2% and Namululi [27] 3.7% in the DRC, and Rakotoniaina [14] in Madagascar with 3.21%.

This prevalence of HBV among blood donors is lower than in some studies: 20% in Tanzania [16] , 14.96% in Burkina Faso [45] , 14.0% in Nigeria [17] , 4.7% in Ethiopia [20] and 8.8 in Uganda [21] . However, it is higher than India’s 1.1% [1] , in Nepal 1.2% [22] , in Canada 0.007% to 0.06% [46] , in Iran 0.15% [47] , China 1.085% [48] , Italy 0.007 [49] and Rwanda 2.8% [21] .

In the Democratic Republic of Congo, this seroprevalence is lower than Kakisingi [25] 8.01% and Michel [6] 6.8% in Lubumbashi, Batina in Kisangani 6.0% [7] , Mbendi in Kinshasa 9.2% [24] ; greater than 1.6% obtained by Kabamba Nzaji [28] in rural Kamina; and close to 3.7% of Namululi [27] and Kabinda [33] 4.2% of volunteer donors in Bukavu. Infectious risk in blood recipients appears to be certain in all provinces of the DRC and viral hepatitis B continues to be the reason for exclusion from donating blood. This risk is more acute in developing countries than in developed countries [47] . The difference between countries and certain environments relative to others is related to socioeconomic status, the level of education of the population, the organization of the health system, the vaccination status of the population and the quality of selection Of candidates for blood donation [47] [50] .

The time-series trend in the evolution of the seroprevalence of HBV infection in our study does not make it possible to give a serious and accurate judgment on the evolution of HBV infection in our environment. The peak was observed in 2015 with 9.4% while 0.3% in 2014 and 0.7% in 2106. It would be necessary to wait for the evolution of this seroprevalence in the following years to make the judgment. However, we believe that on the whole, this fluctuating behavior would be influenced by family donors known as donors at risk of transfusion-transmitted infection (TTIs) [32] [40] [41] [51] .

In our study, the observed seroprevalence of HBV infection in females (4.4%) was higher than that of males (3.6%). The difference observed is not statistically significant (p > 0.05). This was mentioned by Michel [6] in the DRC. Similarly, the prevalence of HBSAg in blood donors aged 18 to 38 (4.2%) and 39 to 58 years (2.7%) was not statistically significant (p > 0.05). Unlike Xie [10] , for who age was associated with the high seroprevalence of HBV infection in Equatorial Guinea. On the other hand, the blood donation category is associated with HBV infection.

Family donors were the only ones affected by HBV in our series and the difference observed was significant (p < 0.05) [6] . It is here that the need for NBTP to organize public awareness campaigns in favor of regular voluntary blood donations in order to achieve the WHO 2020 targets: 100% voluntary donations [52] .

For this study, age and sex are not statistically associated with the occurrence of Hepatitis B infection. Michel [6] and Batina [7] fund the significative association between age and the AgHBSAg in Lubumbashi and Kisangani (DRC). The rural environment has been identified as associated with the risk of transmission of hepatitis B by Kabinda [33] , which requires the strengthening of epidemiological surveillance measures for blood donors.

Apart from the risk of contamination of the blood recipient during the transfusion discussed in this work, it is useful to highlight the limits of our strategy of securing blood donations. Indeed, in addition to the fact that the NBTP recommends the use of a single rapid diagnostic test (RDT) to assess the risk of HBV infection, Determine HBsAg tests are recognized to be less sensitive in some studies [53] [54] [55] . The ELISA chain can be considered as an alternative for confirmation of the results [25] [26] [34] . In Madagascar, in the CHUA-JRA Ampefiloha Immunology laboratory, the results obtained during the evaluation of the rapid tests for the detection of HBsAg showed a sensitivity of 96.1%, a specificity of 93.2%, 93.6% PPV (positive predictive value), 95.8% NPV (negative predictive value) for the Determine HBsAg^® Kit, whereas optimal diagnostic criteria require sensitivity and specificity greater than 98% [55] .

A study conducted in India [56] between 2004 and 2005 revealed that 1027 cases of hepatitis B surface negative antigen were positive in 18% antibody to HBV antibodies and 21% with DNA-HVB. In our study series, no serological results were confirmed, which may limit the scope of our work.

Determine HBsAg^® is a qualitative, in vitro, visual-quality immunoassay for the detection of hepatitis B surface antigen (HBsAg) in human serum, plasma or whole blood [13] [57] [58] . No test can absolutely guarantee that a sample does not contain low concentrations of HBsAg, such as those presented at a very early stage of infection. Therefore, a negative result does not exclude the possibility of exposure to HBsAg or infection with HBsAg [31] [34] [57] [58] .

In order to increase our ability to diagnose and distinguish acute HBV infection from chronic infection in endemic Congolese we recommend: (1) That the NBTP uses two RDTs to diagnose HBsAg (instead of a single test currently performed): we are a low-income country and the cost of HBsAg research by RDTs would be affordable for all Structures; (2) Long-term use of ELISA [23] [34] . In the absence of ELISA, detection of HBsAg may be associated with the patient’s symptoms and other hepatitis B viral serum markers such as anti-HBc, anti-HBc and viral DNA ( There are low cost automata) depending on whether or not they have been vaccinated [24] [57] [59] . Deoxyribonucleic acid (DNA) from HBV can be detected two to three weeks prior to the detection of HBsAg [60] . For Blanco et al. [61] in Argentina, the nucleic acid test contributes greatly in reducing the potential infectious risks of transmission of hepatitis B virus.

Anti-HBc is the first antibody to appear in serum following exposure to HBV, less than one month after the onset of HBsAg. It is not recommended for the detection of hepatitis B but is a useful marker in the context of acute hepatitis B diagnosis in endemic areas [24] [59] . In Malaysia, one thousand HBsAg negative subjects were found to be 87.3% positive for Anti-HBc by ELISA [43] . However in our context, no paraclinic examination is very necessary than the better selection of blood donor candidates (pre-test counseling).

Securing blood donations is a responsibility of the government [50] and its partners who should make better supplies of good quality blood to the Congolese population. This includes regular voluntary donations, good quality pre-test counseling, more effective screening and diagnostic tests, training of blood transfusion personnel and the availability of sufficient blood banks and epidemiological follow-up Seroprevalence in both urban and rural areas.