CHAPTER ONE

1.0                                                    INTRODUCTION

Hepatitis C virus (HCV) is a small enveloped virus measuring 55-65nm in size. It is a positive sense single stranded RNA virus of the family Flaviviridae and genus Hepacivirus (Kapoor et al., 2011). It is the causative agent of human hepatitis C infection, although it has been found to infect chimpanzees, dogs, horses, and rodents (Rogo, 2011; Burbelo et al., 2012; Kapoor et al., 2013; Quan et al., 2013). Hepatitis C virus particle is made up of an RNA core of genetic material, surrounded by an icosahedral protective protein. This is further encased in a lipid envelope derived from the host. The viral glycoproteins, E1 and

E2 are embedded in the lipid envelope (De-Beeck et al., 2003; Igwe et al., 2010). Hepatitis C virus encodes a single polyprotein of 3010-3011 amino acids which is processed into structural and non-structural proteins (NS). This is made possible with the aid of cell signalases and viral proteases.

Hepatitis C genome consists of a single open reading frame (ORF) that is made up of 9600 nucleotide base long (Kato, 2000). The ORF possess highly conserved nontranslated regions (NTR) in its 5′ and 3′ ends. In the 5′ end, there is an internal ribosome entry site (IRES) which allows the RNA to bind to the ribosomes close to the codon to start codon of the ORF. Based on genetic differences between HCV isolates, the virus is classified into seven genotypes (1-7) (Nakano, 2011). These subtypes are further broken into quasi species based on genetic diversity (Christian, 1996) and high error rate on the part of the virus RNA dependent RNA polymerase. The entry of the virus into the host is as a result of complex interaction between virions and cell surface molecules (Zeisel et al., 2009; Kohaar et al., 2010). The structure and replication of HCV is poorly known due to lack of efficient cell culture system, difficulty to grow or develop in cell culture as well as striking heterogenicity in density (Kawo et al., 2012). The virus replicates mainly in the hepatocytes of the liver, where it is estimated that daily each infected cell produces approximately fifty (50) virions with a calculated total of one trillion virions generated

(Bartenschlager and Lohmann, 2000).

Hepatitis C virus was formally known as non A non B hepatitis (Alter et al., 1990; Brooks et al., 2013). In the 1980s investigators from the Centres for Disease Control and Prevention (CDC) identified the virus. Hepatitis C infection ranges in severity from a mild illness lasting a few weeks to a serious lifelong illness and hepatocellular carcinoma (Alter, 2007; WHO, 2013). This virus is most commonly transmitted through exposure to infected blood. This can occur through contaminated blood transfusion, blood products and organ transplant (WHO, 2013), although the most common route of HCV infection is through injection drug use (IDU) (Afolabi et al., 2012; Suresha et al., 1996). The virus may be sexually transmitted, although this is rare and usually only occurs when sexually transmitted diseases (STD) that causes open sores and bleeding is present (Liu and Wei, 2007). Other risk factors involve parenteral exposures with contaminated equipment, tattooing, body piercing, accidental needle stick injury among health workers and perinatal transmission in infants born to HCV positive women (Prati, 2006; Igwe et al., 2010).

The incubation period for hepatitis C is 2 weeks to 6 months and approximately 80% of people do not exhibit any symptoms following initial infection (Gao, 2011; Kawo et al., 2012; WHO, 2013). The viral infection does not really manifest symptoms in majority of people, the infection becomes chronic in most cases and is typically characterized by a prolonged period of no symptoms.  

Hepatitis B infection is a liver disease that results from infection with a virus called

Hepatitis B virus (CDC, 2013). It is a DNA virus of the family Hepadnaviridae, genus Orthohepadnavirus and species Hepatitis B virus (Pungpapong et al., 2007; Willey et al., 2013). The viral particle consists of an outer lipid envelope and an icosahedral nucleocapsid core which is composed of protein. The outer envelope contains proteins that are involved in viral binding and entry into susceptible cells. The outer surface or envelope contains hepatitis B surface antigen (HBsAg) and surrounds the inner nucleocapsid core that contains hepatitis B core antigen (HBcAg) (Willey et al., 2013).

The viral genome consists of a partially double stranded circular DNA, with up to 30203320 nucleotides and viral isolates share 80-90% nucleotide homology (Brooks et al., 2013; Willey et al., 2013). WHO (2013) posited that people at high risk include prison inmates, IDUs, people who frequently require blood and blood products, mentally ill persons, people with multiple sexual partners and health-care workers. The virus is found in body fluids and blood and it is transmitted from person to person through sex, tattooing, body piercing with unsterilized equipment, sharing of equipment like razor, toothbrush and IDU. Transmission from mother to child during childbirth where equipment are not adequately sterilized can also occur (Ugbebor et al., 2011).

The disease is either acute or chronic (Shepard et al., 2006). The acute disease is a short term illness which occurs within six months after the individual is exposed to the virus and does not always lead to chronic infection (CDC, 2013). The likelihood of developing a chronic infection depends on the age at which a person becomes infected (Shepard et al., 2006). Young children less than six years old are most likely to develop a chronic infection when infected with the virus and infants infected during the first year of life develop chronic infection by 80%-95% (Brooks et al., 2013). Five percent of adults develop chronic infection and 15-25% of adults who become chronically infected during childhood die of liver cirrhosis or cancer related to HBV (CDC, 2013).  

1.2        Statement of the Research Problem

It is estimated that about 200 million people in the world (about 3% of the world population) are infected with HCV (Ugbebor et al., 2011; WHO, 2013). Of the 2 billion people who have been infected with the HBV globally, more than 350 million have chronic infection and over 20 million people are infected annually with this virus (Ugbebor et al.,

2011; Akinsegun et al., 2012). It occurs frequently in Nigeria and about 12% of the Nigerian population is infected with HBV (Akinsegun et al., 2012). 

Hepatitis C virus induces end stage chronic liver disease and it is the leading cause of liver failure (Sheyin et al., 2012) even hepatocellular carcinoma and this is a major growing public health problem (Afolabi et al., 2012). The major problem with HCV infection is that 85% of individuals initially infected with the virus become chronically infected, usually for decades (Gao, 2011; CDC, 2012; WHO, 2013) and the other 15% simply have acute infection which resolves in few weeks or months (CDC, 2012). The infection is often asymptomatic but once established, chronic infection can progress to scarring of the liver (fibrosis) and advanced scarring (cirrhosis) which is generally apparent after many years (Ray and Ryan, 2004) or life threatening oesophageal varices and gastric varices which is responsible for thousands of death each year (Kawo et al., 2012).  Those who develop cirrhosis or liver cancer may require a liver transplant and the virus universally recurs after transplantation (Afolabi et al., 2012).

The Department of Health and Human Services, CDC (2011) posited that hepatitis C is the most common type of hepatitis found in jails and prisons. People with mental illness are likely to be over represented in high-risk categories for infection with pathogens with similar routes of transmission, such as HBV and HCV (Stanley et al., 2001). Occurrence of this virus among inmates in the United States is 10 to 20 times that of the occurrence observed in the general population; this has been attributed to high risk behaviour in prisons such as IDU and tattooing with non sterile equipment (Vescio et al., 2008; Imperial, 2010). It is estimated that nearly half of prison inmates share unsterilized tattooing equipment (Jafari et al., 2010). 

Hepatitis B virus and HCV co-infection is very common because of the shared modes of transmission and subjects with high risk of parenteral infections tend to have this (Chi-Jen and Shou-Dong, 2008). A clinical and laboratory study showed that HBV and HCV coinfection causes severe liver disease than mono infection with either HBV or HCV and it is associated with a higher prevalence of liver cirrhosis and hepatocellular carcinoma as compared with mono infection (Chi-Jen and Shou-Dong, 2008).

Hepatitis C virus is spread by blood -to- blood contact (Gao, 2011; Brooks et al., 2013).

The viral infection is common in prison populations, mostly among those with history of IDU, tattooing and sharing of shaving equipment (Teutsch et al., 2010).  Nearly 50% of conviction of French prisoners is as a result of drug trafficking (Semaille et al., 2013).  Intravenous drug use is the major route of HCV transmission worldwide after the introduction of approved blood screening measures before transfusion in 1992 (Maheshwari et al., 2010; Gravitz, 2011; Afolabi et al., 2012). 

In Nigeria, studies have been carried out on the prevalence of HCV among pregnant women and blood donors. Sheyin et al. (2012) reported a prevalence rate of 4.5% among pregnant women in Kaduna State, Bala (2012) reported a prevalence of 2.5% among pregnant women in Maiduguri. Afolabi et al. (2012) reported 2.7% among blood donors in

Ibadan, and a prevalence of 6.0% among blood donors in Jos was reported by Egah et al. (2004). Pennap et al. (2010) had reported 13.3% prevalence among people of a local community in Keffi while Adoga et al. (2009) carried out a study among inmates in Nasarawa State and had a prevalence of 12.3%.  The prevalence of HCV among mentally ill individuals in Nigeria has been found to be 4.2% (Omoaregbe et al., 2013). 

Many Studies on HCV and HBV have been conducted in Nigeria but among pregnant women and blood donors. However, there is dearth of published work on the prevalence of

HCV among prison inmates and psychiatric patients in Kaduna State.

1.3        Justification

Since there is dearth of published information on the prevalence of HCV and HBV in Kaduna State among inmates and psychiatric patients, this study will provide data on the prevalence of HCV and HBV among these populations. The data generated by this study will serve as baseline information for the prevention and control of these viruses and for further studies among prison inmates and psychiatric patients.

1.4        Aim

This study aimed at determining the prevalence of HCV and HBV infections among prison inmates and psychiatric patients in Kaduna Metropolis, Nigeria.

1.5        Specific Objectives

The specific objectives of this research were to:

1.      Screen for HCV antibodies and HBsAg among prison inmates and psychiatric

patients in       Kaduna Metropolis.

2.      Detect HCV RNA using reverse transcription polymerase chain reaction (RTPCR).

3.      Determine the risk factors that predispose individuals to HCV and HBV infections.

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