The Presence of Hepatitis B Envelope Antibody in Patients Who Have Been Previously Screened for the Surface Antigen
Chapter One
Objectives of study
- To determine the presence of Hepatitis B surface antigen among patients who have previously been screened for the antigen attending some hospitals in Kano Metropolis.
- To determine the effect of some sociodemographic variables on the seropositivity of individuals to Hepatitis B.
- To determine the possible risk factors associated with Hepatitis B infection.
- To determine the percentage of women of childbearing age among the study population who are susceptible to HPVB19.
CHAPTER TWO
LITERATURE REVIEW
Historical Background of Hepatitis B Virus.
The early evolution of the Hepatitis B, like that of all viruses is difficult to establish. The divergence of Orthohepadnavirus and avihepadnavirus occurred approximately 125,000 years ago (van Hemert et al., 2011). Both the Avihepadna and Orthohepadna viruses began to diversity about 25,000 years ago (van Hemert et al., 2011).
Hepatitis is characterized by distortion of the normal hepatic lobular architecture due to varying degree of necrosis of individual liver cells or group of liver cell acute, (co- inflation) or chronic (super inflection) inflammation and Kupffer cell enlargement and proliferation (super infection). There is usually some degree of disruption of normal bile flow, which cause, jaundice. The severity of the disease is highly variable often unpredictable (Taura et al, 2008). The disease has an enormous impact on health and national economy of many countries.
Hepatitis B virus (Fig 2.2) is classified in the family Hepadnaviridae. It occurs as eight distinct genotypes, designated A to H (Kramvis et al., 2005), but it is controversial as to whether the outcome of the infection is influenced by the genotype (Krajden et al., 2005). The genotypes have a distinct geographical distribution and are used in tracing the evolution and transmission of the virus (Kramvis et al., 2005). Differences between genotypes affect the disease severity, course and likelihood of complication, and response to treatment and possibly vaccination (Kramvis et al., 2005). The hepatitis B virus is a blood-borne pathogen approximately 75 – 200 times more infectious than the human immunodeficiency virus (HIV), and hyper-endemic in most parts of sub-Saharan Africa (Bowyer et al., 2011).
Hepatitis B virus causes liver infection that can be life-threatening and often leads to chronic liver disease, liver cirrhosis, and liver cancer. The viral infection is a major global health problem which account for about two billion infected cases and 400 million chronic infections worldwide (Bello et al., 2011). Despite the existence of a safe and effective vaccine HBV is hyperendemic in Asia and sub-Saharan Africa. Nigeria remains a hyperendemic area for Hepatitis B virus infection with an estimated 12% of the total population being chronic carriers (Ugwuja, 2010). Many HBV infections are either asymptomatic or never reported, so the actual number is estimated to be approximately ten-fold higher.
CHAPTER THREE
MATERIALS AND METHODS
Study Area
This study was conducted in Kano State. Kano state occupies part of the North West region of Nigeria. It shares boundaries with Kaduna, Bauchi, Jigawa and Katsina States. The location of Kano state is between 11030 N and 8030 E of the equator and occupies an area of approximately 20,131 square kilometres. The state is divided into three senatorial zones and has 44 Local Government Areas. It has a population of about 9.4million (NPC, 2006). Kano is cosmopolitan in outlook and the urban drift from rural areas within the state, other states in Nigeria and West Africa, has provided a steady stream of migrants adding to the growing population of the state. Kano city is characterised by overcrowding and overburden social amenities.
Study Population
The study population comprised of male and female individuals 0-70 years old from all walks of life who reported at two health care facilities in Kano from January to August 2009. The health care facilities were Aminu Kano Teaching Hospital (AKTH) and Hasiya Bayero Paediatric Hospital (HBPH) (both in Kano State).
CHAPTER FOUR
DATA ANALYSIS AND RESULTS PRESENTATION
Table 4.1: Distribution of Patients by Possible Risk Factors
CHAPTER FIVE
DISCUSSION OF FINDINGS, CONCLUSION AND RECOMMENDATION
Discussion
The prevalence of HPVB19 IgG antibody obtained in this study was 41.5% which suggests that HPVB19 infection is endemic in Kano metropolis. This result is almost similar to the prevalence of 39.5% reported in Jos (Girei et al., 2010) and 39.9% in India but lower than the prevalence of 85.4% reported in Zaria (Ujo et al., 2012). Prevalence ranges of 60-70% have been reported from developed countries such as England (Cohen and Buckley, 1988) and lower prevalence of 16.2% has been reported in Singapore (Matsunag et al., 1994). These discrepancies could be due to differences in the specificity and sensitivity of the assays used. Hepatitis B infection infection has been reported in many countries around the world and the seropositive rate varies by location (Salimi et al., 2008). However the presence obtained in this study is within the range of 35%-70% reported from different serosurveys among the general healthy population in different regions of the world (Kelly et al., 2000).
Several studies in different regions of the world have identified different socio-demographic variables like age, gender, socio-economic status and environmental conditions as risk factors for acquisition of parvovirus B19 infection (Alao et al., 2010). For example, age has been consistently shown to be a major predictor of anti parvovirus B19 IgG seropositivity (Ooi et al., 2002; Mazyar and Abdolvahab, 2007; Alao et al., 2010).
This study showed that seropositivity increased with age. This increasing seropositivity with increasing age is consistent with the work of Girei in Jos (Girei et al., 2010) and those reported in other countries (Ooi et al., 2002; Salimi et al., 2008;
Kishore et al., 2010). For Parvovirus B19, seropositivity implies immunity, because increase in the presence with age means that the proportion of individuals susceptible to parvovirus B19 decreases with age (Gilbert et al., 2005; Salimi et al., 2008).
However, the finding contrasts the result of Ujo and colleagues (2012) who reported that seropostivity did not increase with age. This could be due to the fact their study was carried out in children with sickle cell disease whereas the present study was carried out among the general population aged from 0-70 years.
The prevalence obtained among patients who have previosly been screened for the antigen age group >51 years in this study is similar to 50% found in India (Kishore et al., 2010) and slightly lower than 55% reported in Malaysia (Ooi et al., 2002) for the same age group. This difference could be due to dwindling immune response in the elderly, as a result of natural waning of antibodies with time as the antibodies could have decreased to a level beneath the detection limit of the test used here.
This study however did not demonstrate any association between gender and seropositivity as the prevalence rates were not significantly different between male and female patients. However a higher seropositivity was observed in female patients than in male patients. This is in agreement with the findings previously reported in Malaysia (Ooi et al., 2002), Iran (Salimi et al., 2008) and Nigeria (Girei et al., 2010). The reason for this finding could be because women are always in contact with children.
Marital status did not affect the prevalence of the HPVB19 in this study. No statistically significant difference in the positivity was evident among the married patients and the unmarried individuals. This could be due to the fact that transmission of parvovirus infection is not through sexual route. A study on blood donors in India did not find any association between HPVB19 and marital status (Kishore et al., 2010).
This study determined the effect of occupation, type of residence as well as number of people living in house on seropositivity of the viruses. This study observed a higher positivity among farmers, bike riders and unskilled labourers. This finding conforms to work of Kishore et al. (2010) among blood donors in India where high positivity was observed among unskilled labourers, could be explained by their poor living conditions such as poor housing and low educational levels. Outdoor activities could lead to more exposure and thus contact with infectious agents and could be a reason for higher prevalence among these occupational groups. High positivity observed in this study among full time housewives could also be due to the fact that women are always in contact with children both at home and outside the home. This finding does not conform to the work of Ujo et al. (2012) who did not find any association between occupation and HPVB19 among parents of children in their study (Ujo et al., 2012).
The relationship between socio-economic status and health outcome is well known (Alao et al., 2010). World Health Organization (1989) proposed a definition of standards of living “Income, occupation, standard of housing, sanitation, nutrition and the level of provision of health, educational, recreational, and other services may all be used individually as measures of socioeconomic status and collectively as an index of the standard of living.”(Kishore et al., 2010).
Education is a major factor influencing health status. The world map of literacy closely coincides with the maps of poverty, malnutrition, ill health, and high mortality rates. Studies have indicated that education, to some extent compensates the effects of poverty on health, irrespective of the availability of health facilities (Kishore et al., 2010). In this study the highest prevalence was observed among those without formal education and lowest prevalence was among the highly educated. The finding is consistent with findings of Kishore and colleagues conducted among blood donors and HPVB19 in India who also reported higher prevalence among illiterates, low educated group and lowest among the highly educated group (Kishore et al., 2010).
CONCLUSION
The findings in this study confirmed the presence of Hepatitis B infection infection in Kano State with sero-prevalence comparable to the rates found in various countries in the world. Sero-prevalence of HPVB19 among patients who have previosly been screened for the antigen was low leaving a large proportion (58%) of the population in Kano still susceptible to B19 infection. The study also showed that about 52% of women of childbearing age were still susceptible to HPVB19. This study also showed the effect of formal education, occupation and number of persons living in a house on seropositivity of individuals to HPVB19.
The prevalence of 8.5% obtained for the HBV showed that HBV infection is endemic in Kano and still poses as a public health problem which must be addressed.
It is very important, especially for health providers and policy makers, to recognize the health implication of these viruses in this area and design effective preventive programs.
RECOMMENDATIONS
In view of low prevalence of HPVB19, obtained in this study hence high susceptibility among population coupled with lack of data regarding the presence of HPV B19 among childbearing women in Kano, there is need for awareness on the virus to educate the public on the risk especially when pregnant.
In view of low prevalence of HPVB19 among pregnant women a prospective study is therefore recommended to investigate the prevalence of B19 parvovirus associated non immune hydrops and stillbirths in order to plan a national preventive approach.
There is also need to investigate the presence of HPVB19 among blood donors for probable inclusion as routine screening since Parvovirus B19 can be transmitted through blood products.
There is need for further investigation on the main risk factors associated with HBV infection in Kano state.
This study was hospital based, therefore there is need for a community based study, to detect the presence of current infection by detecting IgM and if possible molecular epidemiology researches as well as in the population in order to find out the persistence of HPVB19 DNA in tissues.
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