Globally, hepatitis C Virus
(HCV) infection is responsible for a large proportion of persons with liver
disease, including cancer. The infection is highly prevalent in sub-Saharan
Africa. West Africa was identified as a geographic origin of two HCV genotypes.
However, little is known about the genetic composition of HCV populations in
many countries of the region.
Using conventional and next-generation sequencing
(NGS), we identified and genetically characterized 65 HCV strains circulating
among HCV-positive blood donors in Kumasi, Ghana. Phylogenetic analysis using
consensus sequences derived from 3 genomic regions of the HCV genome,
5'-untranslated region, hypervariable region 1 (HVR1) and NS5B gene,
consistently classified the HCV variants (n = 65) into genotypes 1 (HCV-1, 15%)
and genotype 2 (HCV-2, 85%).
The Ghanaian and West African HCV-2 NS5B sequences
were found completely intermixed in the phylogenetic tree, indicating a
substantial genetic heterogeneity of HCV-2 in Ghana. Analysis of HVR1 sequences
from intra-host HCV variants obtained by NGS showed that three donors were
infected with >1 HCV strain, including infections with 2 genotypes. Two
other donors share an HCV strain, indicating HCV transmission between them. The
HCV-2 strain sampled from one donor was replaced with another HCV-2 strain
after only 2 months of observation, indicating rapid strain switching.
Bayesian
analysis estimated that the HCV-2 strains in Ghana were expanding since the 16th century. The blood donors in Kumasi, Ghana, are
infected with a very heterogeneous HCV population of HCV-1 and HCV-2, with
HCV-2 being prevalent. The detection of three cases of co- or super-infections
and transmission linkage between 2 cases suggests frequent opportunities for
HCV exposure among the blood donors and is consistent with the reported high
HCV prevalence.
The conditions for effective HCV-2 transmission existed for ~
3–4 centuries, indicating a long epidemic history of HCV-2 in Ghana.
Below: PFnet of all
sequences present in two patients at different time points. Each time
point is shown with a different color. Sequences found on the first time point
are shown in red and the second time point in blue. Each node represents a
single sequence variant. The size of the node reflects frequency of the
corresponding variant in the population. This network includes all of the links
in any minimum spanning tree. The time interval between each time point is ~2
months.
Below: Bayesian skyline
plot, showing the epidemic history of HCV genotype 2. The thick black
line in the middle represents the estimated mean effective number of infections
through time in years. The two grey lines represent the 95% highest posterior
density of this estimate.
Full article at: http://goo.gl/rfcb1c
By:
Joseph C. Forbi, Guo-liang Xia, David S. Campo, Michael A.
Purdy, Zoya E. Dimitrova, Lili T. Punkova, Pavel Skums, Gilberto Vaughan,
Hajung Roh, Yury E. Khudyakov
Molecular Epidemiology and Bioinformatics Laboratory,
Division of Viral Hepatitis, Centers for Disease Control and Prevention,
Atlanta, Georgia, United States of America
Jennifer E. Layden, Nallely Mora, Richard S. Cooper
Department of Public Health Sciences, Loyola University
Chicago, Maywood, Illinois, United States of America
Jennifer E. Layden
Department of Medicine, Loyola University Chicago, Stritch
School of Medicine, Maywood, IL, United States of America
Richard O. Phillips, Dorcas O. Owusu, Shirley Owusu-Ofori,
Fred Stephen Sarfo, Ohene K. Opare-Sem
Komfo Anokye Teaching Hospital, Kumasi, Ghana, West Africa
Richard O. Phillips, Fred Stephen Sarfo
Kwame Nkrumah University of Science and Technology, Kumasi,
Ghana, West Africa
More at: https://twitter.com/hiv_insight
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