Title:
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Epidemiology, immunology and genetics of viral hepatitis in Aden City, Yemen
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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.
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