Hepatitis B Virus Infection among Prison Inmates in Borno State: Determination of Prevalence of Surface Antigen (HBsAg) and Possible Risk Factors of Disease

Research Article

J Hepat Res. 2021; 6(1): 1041.

Hepatitis B Virus Infection among Prison Inmates in Borno State: Determination of Prevalence of Surface Antigen (HBsAg) and Possible Risk Factors of Disease

Lawan S², Gimba SN¹*, Elyuguda AD², Sabo H¹ and Dadile HM¹

¹Department of Basic Nursing, Shehu Sule College of Nursing and Midwifery Damaturu, Nigeria

²Department of Veterinary Microbiology, University of Maiduguri, Faculty of Veterinary Medicine, Nigeria

*Corresponding author: Saleh Nadabo Gimba, Department of Basic Nursing, Shehu Sule College of Nursing and Midwifery Damaturu, Nigeria

Received: April 12, 2021; Accepted: May 03, 2021; Published: May 10, 2021


An epidemiological study on hepatitis B virus infection among prison inmates in Borno state, Nigeria, was carried out using a questionnaire survey to determine the possible risk factors of the disease and serological method [using an Enzyme Linked Immunosorbent Assay (ELISA)] to determine the prevalence of hepatitis B surface antigen (HBsAg) among the inmates. The study was conducted in correctional facilities in Maiduguri, Biu and Bama local government area of Borno State. Out of a total of 300 sera tested, 49 (16.3%) had detectable ELISA antibody to HBsAg. A significant difference (p<0.001) in seroprevalence of HBsAg among inmates of different educational qualifications was observed and those with higher education had the highest prevalence (20.9%). Although there was no significant difference in prevalence of HBsAg among the different age groups, the age group 60-69 years had the highest infection rate (33.3%). Homosexuality and duration of stay in prison are shown to be significantly associated with HBsAg infection (P<0.05) among inmates. A significant gender difference was noted among inmates with the males (16.1%) having higher prevalence when compared with females (20.0%). Analysis of spatial distribution of prevalence of HBsAg showed that Maiduguri prison had (20.5%), followed by Biu prison (12.7%) and Bama prison (6.7%) and there was significant difference (P<0.05) in prevalence between prisons. There was no significant (P>0.05) association of prevalence of HBsAg with marital status or occupation of prison inmates. In conclusion, hepatitis b virus infection was found to be prevalent among prison inmates in Borno state with homosexuality and duration of stay in prison as risk factors.


Hepatitis B infection is an acute infection of liver in which the liver cells are inflamed [1]. Viral hepatitis causes considerable mortality both from acute infection and chronic disease conditions and ranks among the ten top killer diseases world-wide [2]. Hepatitis virus lives in the blood and other body fluids and is transmitted from person to person through unprotected sexual intercourse with an infected person, sharing infected needles, or other sharp objects that break the skin [3]. Hepatitis B Virus (HBV) infection is worldwide and a serious global health problem which accounts for over two billion infected cases and 400 million suffering from chronic infections worldwide [4,5]. It has been reported that hepatitis B related illnesses cause an estimated 1-2 million deaths per year worldwide [2].

The HBV infection varies widely across the world from high (>8 %) in Africa, Asia and the Western Pacific, intermediate (2-7.9 %) in Southern and Eastern Europe to low (<2 %) in Western Europe, North America and Australia [2,6]. Nigeria, a tropical country, is highly endemic for HBV infection and about 75% of its population is likely to have been exposed to the virus at one time or the other in their lives [7]. The prevalence rate of HBV in Nigeria is high and 19 million Nigerians are infected with the virus [8] and have reached hyper-endemic levels with the sero-prevalence of Hepatitis B surface antigen estimated to range from 10 to 40% [5,9]. Hepatitis B virus is a blood borne pathogen, which is efficiently transmitted by percutaneous or per mucosal exposure to infectious blood or other body fluids [10]. Hepatitis B virus is present in the blood, saliva, semen, vaginal secretions, menstrual blood, and to a lesser extent, perspiration, breast milk, tears, and urine of infected individuals [11]. The routes of transmission vary according to the endemicity of the HBV infection. In areas of high endemicity, perinatal transmission is the main route of transmission, whereas in areas of low endemicity, sexual contact amongst high-risk adults is predominant [12].

Unlike in Europe and America, there are limited published data on HBV infections among prison inmates in Nigeria and the rest of Africa despite its tremendous importance in public health policy formulation [13]. There is currently no periodic national survey for HBV in either the Nigerian general population or prison inmates; however, prisoners worldwide are at high risk of contracting HBV, especially those who engage in high-risk behaviours such as intravenous drug use, sharing of nail cutter, clipper and or homosexual activities [13]. Prisoners are therefore potential reservoirs of infection to the uninfected entrants and the general non-incarcerated population upon regaining freedom.

In this study, a cross-sectional survey was carried out in selected correctional facilities in Borno State, Nigeria, to determine, the seroprevalence of hepatitis B surface antigen and possible risk factors associated with this silent and deadly viral infection.

Materials and Methods

Study area

The study was conducted in correctional facilities in Maiduguri, Biu and Bama local government areas of Borno state. Borno state lies between latitude 100N and 130N and longitude 120E and 150E. The state has an area of about 69,436 km² [14]. The state is located in the North eastern part of Nigeria, and has an estimated population of 4.2 million people [15]. Borno state has a hot climate with average peak daily temperature ranging between 34⁰C and 40⁰C especially in April and May. The rainy season lasts from June to September in the North which has a Sahelian vegetation and May to October in the South with Sudan vegetation [16,17].

Study population and sample size determination

Three hundred prison inmates were employed (age ranged 18 to 69 years) comprising 285 males and 15 females for this study from the total number of five hundred and seventy nine(579) inmates , out of which 404 from maximum security prison, 97 from Biu prison and 78 from Bama prison respectively in Borno state. The period of study was conducted between November through January 2012/2013. The previous prevalence used for this study was 11.6% by Harry et al. The sample size was obtained using the formula for Sample Size = n/1-(n/ population size).

Where n=z²pq/d²;

n=number of participants required in the survey,

Z= normal standard deviation at 1.96 (which corresponds to 95% confidence interval, P=prevalence of Hepatitis B surface antigen from previous study;

q = 1-p and d= degree of accuracy/precision expected set at 0.05 [18].

Ethical clearance

The study was approved by the State Ministry of Health Maiduguri, Borno state, in accordance with the code of ethics for biomedical research involving human subjects. Official consent of the State’s highest prison authority, the State Comptroller of prisons, was also obtained.

Questionnaire survey

Structured open ended questionnaires were prepared and administered on the spot to each of the participating inmates (Appendix A). The inmates were asked about their socio-demographic details including prison identification number, sex, age, ethnicity, residence, educational qualification, occupation and marital status. Information was also asked about the mode of imprisonment and jail term and exposure to risk factors associated with blood transfusion, intravenous drug use as well as history of sexual behaviour including sexual orientation, number of sexual partners, homosexuality and history of sexually transmitted diseases and sharing of clippers and sharp objects. Information on vaccination against HBV infection was also obtained from the inmates.

Serum sample

Venous blood samples were collected from three hundred participants using a sterile 5 ml syringe and needle. The samples were collected into sterilised plain vacutainer tubes and conveyed to laboratory for serum separation. The blood samples were kept at room temperature to clot. Serum samples were harvested from the clotted blood by centrifuging at 2,000 revolutions per minutes for 10 minutes. The harvested serum was put into cryotubes and stored at -20⁰C until tested.

Assay of serum samples for HBsAg

The serum samples were analysed for the presence of HBsAg using the sandwich Enzyme Linked Immunosorbent Assay (ELISA) [MonolisaTM HBsAg ULTRA Bio-Rad-F 92430-Marnes la Coquette, LOT 2J0152, France]. The MonolisaTM HBsAg ULTRA has an analytical sensitivity of 0.2 ng/ml; assay sensitivity of 99.98%, and specificity of 100%. The test is based on the principle of the sandwich ELISA using monoclonal antibodies and polyclonal antibodies selected for their ability to bind themselves to the various subtypes of HBsAg in serum, which is a marker of acute HBV infection. The test was conducted following the manufacturer’s instructions and the microtitre plates were read at a wavelength of 450 nm, using ELISA reader (E-max-reader, precision microtitre plate reader MDS –Analytical technique USA).

Principle of sandwich ELISA

Antibodies sandwich ELISA may be most useful in detecting antigen because they are frequently between 2 and 5 times more sensitive than those in which antigen is directly bound to the solid phase. To detect antigen, the wells of microtiter plates are coated with specific (captured) antibody followed by incubation with test solutions containing antigen. Unbound antigen is washed out and an antigen specific antibody conjugated enzyme (i.e. developing reagent) is added, followed by incubation. Enzyme labelled antibody can be produced in the same animal that produced passively adsorbed antibody, or from a different species immunised with the same antigen that is captured. Unbound conjugate is washed out and substrate is added. After incubation, the degree of substrate hydrolysis is measured. The amount of substrate hydrolysed is proportional to the amount of antigen in the test solution.

Procedure of sandwich ELISA (MonolisaTM HBsAg ULTRA)

The procedure of the sandwich ELISA was followed in accordance with the manufacturer’s instruction. Briefly, 100μl of negative control was added into a selected wells and addition of 100μl of positive control into appropriate pre-coated wells with monoclonal antibody. This was followed by the addition of 100μl of the test sera into the remaining wells. Fifty microlitres (50 μl) of conjugate solution consist of (conjugate diluent- bovine immunoglobulin and mouse immunoglobulin, and conjugate-consist of mouse monoclonal anti HBsAg antibodies and goat polyclonal antibodies) was then dispensed into all the wells. The plate was then covered with a new adhesive film and incubated for 1 hour 30 minutes at 37⁰C. After the incubation the plate was emptied by aspiration and washed for a minimum of 5 times. The plate was dried by turning them upside down on absorbent paper. One hundred microlitres (100 μl) of freshly prepared substrate solution consist of (substrate buffer-citric acid and sodium acetate; containing H2O2 and DMSO and chromogen pink coloured solution; containing TMB), was dispensed into all the wells and incubated in the dark for 30 minutes at room temperature (16- 300C). The reaction was stopped by the addition of 100 μl of stopping solution (1N Sulphuric acid).

Data analysis

Data obtained from the study were analysed using Statistical Package for Social Sciences (SPSS) Version 16 software. Chi-square and Fisher’s exact test were used to perform categorical comparison and level of significance at 95% confidence interval. P-value less than or equal to (P≤0.05) was considered statistically significant.


Hundred (100%) response rates were recorded for the questionnaire survey. Results of the seroepidemiological survey for HBsAg among prison inmates in Borno state showed an overall prevalence rate of 49/300 (16.3%) (Table 1) The gender distribution of the HBsAg positive reactors indicated 46/285 (16.1%) males and 3/15 (20.0%) females. No significant difference (p>0.05) was observed in the gender distribution of HBsAg in prison inmates. Gender was therefore not a risk factor in this study. Analysis of the age distribution of seroprevalence of HBsAg infection among the prison inmates revealed that the age groups 53-59 and 60-69 years had the highest prevalence rates of 28.6% and 33.3% respectively, followed by the age groups 18-24 (15.0%), 25-31 (15.4%), 32-38 (19.0%) and 39-45 (18.2%) years and the least was 46-52 years (8.3%) (Table 2). There was no significant difference (p>0.05) in the prevalence of HBV infection between the different age groups. Figure 1 below represents the frequency distribution of ELISA Optical Density (OD) values of the HBsAg positive sera from prison inmates. Majority (85.7%) of the positive samples reacted with low to intermediate OD values (1-1.5, 1.6-2.0, 2.1-2.5) as compared to the 14.3% with high OD values (2.6-3.5). Optical density values that are equal to or greater than 1.0 were considered positive. Significant difference (P<0.05) was noted in the prevalence of HBsAg among the different ethnic groups of prison inmates studied (Table 3). The distribution of the prevalence in decreasing order among the different ethnic groups was as follows: Marghi (32.0%), Hausa (23.9%), Michika and Kanakuru (20.0% each), others (Yoruba, Igbo, Igala, Karekare) (18.2%), Gwoza (16.7%), Shuwa Arab (15.8%), Kanuri (13.0%), Babur-bura (10.2%) and Fulani (6.0%) (Table 3).