Disparate distribution of hepatitis B virus genotypes in four sub-Saharan African countries

Details

• Alternative Title:
  J Clin Virol
• Personal Author:
  Forbi, Joseph C. ; Ben-Ayed, Yousr ; Xia, Guo-liang ; Vaughan, Gilberto ; Drobeniuc, Jan ; Switzer, William M. ; Khudyakov, Yury E.
• Description:
  Background
  
  Hepatitis B virus (HBV) places a substantial health burden on Africa. Here, we investigated genetic diversity of HBV variants circulating in 4 countries of sub-Saharan Africa using archived samples. In total, 1492 plasma samples were tested from HIV-infected individuals and pregnant women, among which 143 (9.6%) were PCR-positive for HBV DNA (Côte d’Ivoire, 70/608 [11.5%]; Ghana, 13/444 [2.9%]; Cameroon, 33/303 [10.9%]; and Uganda, 27/137 [19.7%]).
  
  Study design/results
  
  Phylogenetic analysis of the S-gene sequences identified HBV genotypes E (HBV/E, n = 96) and A (HBV/A, n = 47) distributed as follows: 87% of HBV/E and 13% of HBV/A in Côte d’Ivoire; 100% of HBV/E in Ghana; 67% of HBV/E and 33% of HBV/A in Cameroon; and 100% of HBV/A in Uganda. The average and maximal nucleotide distances among HBV/E sequences were 1.9% and 6.4%, respectively, suggesting a greater genetic diversity for this genotype than previously reported (p < 0.001). HBV/A strains were classified into subgenotypes HBV/A1, HBV/A2 and HBV/A3. In Uganda, 93% of HBV/A strains belonged to HBV/A1 whereas HBV/A3 was the only subgenotype of HBV/A found in Cameroon. In Côte d’Ivoire, HBV/A strains were classified as HBV/A1 (11.1%), HBV/A2 (33.3%) and HBV/A3 (55.6%). Phylogeographic analysis of the sequences available from Africa supported earlier suggestions on the origin of HBV/A1, HBV/A2 and HBV/A3 in East, South and West/Central Africa, respectively. Using predicted amino acid sequences, hepatitis B surface antigen (HBsAg) was classified into serotype ayw4 in 93% of HBV/E strains and adw2 in 68% of HBV/A strains. Also, 7.7% of the sequences carried substitutions in HBsAg associated with immune escape.
  
  Conclusions
  
  The observations of pan-African and global dissemination of HBV/A1 and HBV/A2, and the circulation of HBV/E and HBV/A3 almost exclusively in West and Central Africa suggest a more recent increase in prevalence in Africa of HBV/E and HBV/A3 compared to HBV/A1 and HBV/A2. The broad genetic heterogeneity of HBsAg detected here may impact the efficacy of prevention and control efforts in sub-Saharan Africa.
  
  
• Subjects:
  Cluster Analysis DNA, Viral Female Genetic Variation Genotype Hepatitis B Hepatitis B Surface Antigens Humans Male Molecular Epidemiology Molecular Sequence Data Phylogeography Pregnancy Prevalence Sequence Analysis, DNA

  More +
• Source:
  J Clin Virol. 58(1):59-66
• Pubmed ID:
  23871163
• Pubmed Central ID:
  PMC4591023
• Document Type:
  Journal Article
• Funding:
  CC999999/ImCDC/Intramural CDC HHSUnited States/
• Place as Subject:
  Africa South of the Sahara
• Volume:
  58
• Issue:
  1
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:02446a919ca6c4ef860cfae10a11d7a23185f2036a63736ee32e6b0df7b44164
• Download URL:
  https://stacks.cdc.gov/view/cdc/34650/cdc_34650_DS1.pdf
• File Type:
  [PDF - 677.24 KB ]