Low genetic diversity despite hyperendemicity of hepatitis B virus genotype E throughout West Africa.
Sub-Saharan Africa suffers from an excessively high endemicity of hepatitis B virus (HBV), but little is known about the prevalent genotypes. In this study, we investigated the PreS1/PreS2/S genes of 127 viruses obtained from 12 locations in Mali, Burkina Faso, Togo, Benin, Nigeria, Cameroon, and the Democratic Republic of Congo. Except for those obtained from the Cameroon HIV cohort (18/22 HBV genotype A), 96 of 105 sequences belonged to HBV genotype E (HBV/E), and viral DNA was very similar (1.67% diversity) throughout this vast HBV/E crescent, which spans 6000 km across Africa. The low diversity suggests that HBV/E may have a short evolutionary history. Considering a typical mutation rate of DNA viruses, it would take only 200 years for the strain diversity of HBV/E viruses to develop from a single introductory event. The relatively recent introduction of HBV/E into humans would also explain its conspicuous absence in the Americas, despite the forced immigration of slaves from west Africa, until the early 19th century. Infection during infancy is mostly associated with chronic carrier status, and this combination can account for the explosive spread of virtually identical viruses within a community, but whether other routes of long-range transmissions must be considered becomes an important question.
Mulders
Mick N
MN
Institute of Immunology, National Public Health Laboratory, Luxembourg, Luxembourg.
Venard
Veronique
V
Njayou
Mounjohou
M
Edorh
A Patrick
AP
Bola Oyefolu
Akeeb O
AO
Kehinde
M O
MO
Muyembe Tamfum
Jean-Jacques
JJ
Nebie
Yacouba K
YK
Maiga
Ibrahim
I
Ammerlaan
Wim
W
Fack
Fred
F
Omilabu
Sunday A
SA
Le Faou
Alain
A
Muller
Claude P
CP
D000293:Adolescent; D000328:Adult; D000354:Africa, Western / Q000453:epidemiology; D000368:Aged; D002353:Carrier State / Q000821:virology; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000737:chemistry / Q000302:isolation & purification; D019353:Endemic Diseases; D005260:Female; D005814:Genes, Viral; D014644:Genetic Variation; D005838:Genotype; D006509:Hepatitis B / Q000453:epidemiology* / Q000635:transmission / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000235:genetics; D006515:Hepatitis B virus / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D011498:Protein Precursors / Q000235:genetics; D017422:Sequence Analysis, DNA
D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D011498:Protein Precursors; C050806:presurface protein 1, hepatitis B surface antigen; C050807:presurface protein 2, hepatitis B surface antigen