Phylogeography, Risk Factors and Genetic History of Hepatitis C Virus in Gabon, Central Africa

Abstract

BackgroundThe epidemiological and molecular characteristics of hepatitis C virus (HCV) infection in the general population have been poorly investigated in Africa. The aim of this study was to determine the prevalence, genotype distribution and epidemic history of HCV in the Gabonese general population.Methods/Principal FindingsA total of 4042 sera collected from adults in 220 villages in all nine administrative areas of the country were screened for antibodies to HCV. HCV NS5B region sequencing was performed for molecular characterization and population genetic analyses. Of 4042 tested sera, 455 (11.2%) were positive. The seroprevalence of HCV varied significantly by administrative area, with the highest rate in Ogooué-Lolo province (20.4%) and the lowest in Ogooué-Maritine province (3.7%). History of parenteral injections, past hospital admission and age over 55 years were independent risk factors for HCV infection (p<0.0001). Phylogenetic analyses showed that 91.9% of the strains were genotype 4 (HCV-4), 5.7% genotype 1 and 2.2% genotype 2. HCV-4 strains were highly heterogeneous, with more than eight subtypes; subtype 4e predominated (57.3%). Coalescence analyses indicated that subtype 4e was the oldest, with an estimated most recent common ancestor of 1702 [95% CI, 1418–1884]. The epidemic profile indicated that it spread exponentially during the first part of the 20th century, probably by iatrogenic transmission.Conclusions/SignificanceThese results confirm the endemicity of HCV subtype 4e in Gabon and show that its spread is due to a cohort effect, with previous, possibly iatrogenic events. More extensive epidemiological studies are needed to better characterize the route of transmission and the dissemination of HCV in Gabon.

Polymorphisms of Toll-like receptors 2 and 4 in chronically infected hepatitis C patients from north-east Croatia

“…In our study, the highest HCV prevalence was in 31-to 40-and 51-to 60-year-old individuals. This is similar to reports from Italy, central Africa, Japan and China, in which the highest rate of HCV infection was found in patients older than 50 [4,29]. Contrary to our study, the highest HCV prevalence in western Croatia was found in 21-to 30-yearold symptomatic individuals (44%, n = 76).…”

Conservation in China of a novel group of HCV variants dating to six centuries ago

“…In contrast, the endemic subtypes of HCV genotypes 1, 2, and 4 have been found mainly in populations in geographically restricted areas in the sub-Saharan Africa or among African descendants in other geographic regions, but showing persistence for fewer centuries than that we here estimated for those novel Hainan variants [26–29]. The best example of such can be seen in a recent report that has shown the existence of multiple HCV-2 “migrant clusters” moved at some point in the past from West Africa to the other parts of the world.…”

Do differences exist between chronic hepatitis C genotypes 2 and 3?

“…Genotype 3a is the second most common genotype in Europe after genotype 1 4,6 . Genotype 4 is prevalent in the Middle East [12][13][14] and in Central Africa [15][16][17] , while genotype 5 is common in South Africa 1,18 , and genotype 6 is found mainly in South Asia [19][20][21] . Genotype 7 has been found in Vietnamese patients with chronic hepatitis C, although some authors have advocated that it should be reclassifi ed as a subtype of genotype 6 22 .…”