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Title: Epidemiology, immunology and genetics of viral hepatitis in Aden City, Yemen
Author: Bawazir, Amin Ahmed
ISNI:       0000 0004 2677 7045
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2009
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Background: Viral hepatitis is a significant public health problem with millions of humans infected worldwide. There are very few studies of hepatitis in Aden, Yemen. Aims: The study aims to determine the prevalence of viral hepatitis (A, B, e and E), their co-infection with Epstein - Barr virus (EBV), cytomegalovirus (eMV) and human herpes virus (HHV6) and the risk factors for HBV infection among individuals attending primary health care facilities. Risk factors for HBV and Hev infection were also identified in patients with chronic liver disease (eLO), multi-transfusions and those undergoing haemodialysis (HO). The genotypes of HBV are studied. The HBV vaccination coverage in children < 5 years in Aden is also described. Methodology: A cross-sectional study of individuals attending primary health care facilities in Aden was conducted to identify the prevalence of the viruses. Participants were recruited stratified by age. A case-control study of hospital patients with eLO, polytransfusion and HO was used to identify risk factors for HBV and Hf'V. Both cases and healthy participants were interviewed and blood samples were analysed using ELISA assays. A community-based survey of children < 5 years was used to identify vaccination coverage and to interview parents. peR sequencing method was used for HBV genotyping. Results: The overall seroprevalence of exposure to HAV (anti-HAV antibodies), HBV (anti-HBc antibodies), HEV (anti-HEV antibodies) and HeV (anti-Hf'V antibodies) were 86.6%, 16.2%, 10.7% and 0.4%, respectively. HBV and Hev had low prevalence in children and no HBV carriage. Perinatal transmission does not seem to be a major route of transmission for HBV. Acupuncture and cupping are risk factors for chronic liver diseases in this setting. The duration of the haemodialysis and a history of malaria were associated with increased rates ofHBV and Hev infections among polytransfusedIHO patients. This is the first report of the prevalence ofEBV, eMV and HHV6 in Yemen. The three viruses had high seroprevalences and co-infections with another herpes virus or hepatitis viruses were common. The Expanded Programme of Immunisations in Aden has achieved HBV vaccination coverage of 63% in children < 5 years old which was lower than its target (85%), but the highest reported in the country. Lack of parental education and access to health care facilities were associated with lack of vaccination. The predominant genotype of hepatitis B was genotype D. Conclusions: Viral hepatitis is a major public health problem in this community. Viruses causing hepatitis varied from hyperendemic (HAV) to low prevalence (HeV); and prevalence varies with age. None of the children < 15 years were HBV carriers or had Hev infection. The detection rates in the study would classify Aden as a low HBV endemic zone. This is the first description of HEV in Yemen revealing it to be a significant problem. Polytransfusion and HO are important risk factors for contracting HBV and Hev. The information yielded in this study on the prevalence and risk factors for HBV and Hev infection on patients with eLO would improve our understanding on the role of these viruses and the application of preventive and control measures in this population.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available