title: Evolutionary dynamics of HBV-D7 subgenotype in Tunisia.
abstract: Hepatitis B virus (HBV) is the main cause of diseases liver related infecting more than 200 milion persons worldwide. HBV infection shows high level of prevalence in South-East Europe and in Mediterranean basin. In Tunisia, a country with an intermediate level endemicity, HbsAg prevalence ranges from 2 to 5%. Most of the HBV isolates from Tunisia were classified as subgenotype D7 whose circulation is restricted to a specific area of North Africa including Maghreb region. In this paper, the phylogeny of HBV-D7 isolated from 38 Tunisian patients was investigated by analyzing the S gene region of HBV. A Bayesian coalescent-based framework was used to estimate the origin of the HBV-D7 in the country. The Tunisian D7 isolates were found to share a common ancestor whose origin was traced back to 1958. Population dynamics indicated that HBV-D7 epidemic in Tunisia grew exponentially from 1960s to 1990s. After that, the curve reached a plateau around the years 2000 likely due to the implementation of the infant vaccination program in 1996. Epidemiological data suggested that the exponential growth phase was likely sustained by intra-familial transmission events occurring during infancy. Further characterization of HBV-D7 isolates should be performed to evaluate, in the post-vaccination era, the emergence of new transmission routes, and to monitor the efficacy of the vaccination program. J. Med. Virol. 89:469-475, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.|University Hospital Campus Bio-Medico, Rome, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Ciccozzi
authors.affiliation: Department of Infectious Diseases, Viral Hepatitis Research Unit (UR12SP35), University Hospital Farhat Hached, Sousse, Tunisia.|Faculty of Pharmacy, Laboratory of Infectious Diseases and Biological Agents, University of Monastir, Monastir, Tunisia.
authors.forename: Houda
authors.initials: H
authors.lastname: Chaouch
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Lo Presti
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Viral Hepatitis Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Taffon
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Viral Hepatitis Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Umbertina
authors.initials: U
authors.lastname: Villano
authors.affiliation: Department of Cell Biology and Neurosciences, Clinical Diagnostics and Therapy of Degenerative Diseases of the Central Nervous System Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Equestre
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Viral Hepatitis Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Bruni
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Viral Hepatitis Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Marcantonio
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Viral Hepatitis Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Tritarelli
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.|Public Health and Infectious Diseases, Sapienza University, Rome, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Cella
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.|University Hospital Campus Bio-Medico, Rome, Italy.
authors.forename: Aletheia
authors.initials: A
authors.lastname: Blasi
authors.affiliation: Faculty of Pharmacy, Laboratory of Infectious Diseases and Biological Agents, University of Monastir, Monastir, Tunisia.
authors.forename: Mahjoub
authors.initials: M
authors.lastname: Aouni
authors.affiliation: Department of Infectious Diseases, Viral Hepatitis Research Unit (UR12SP35), University Hospital Farhat Hached, Sousse, Tunisia.
authors.forename: Amel
authors.initials: A
authors.lastname: Letaief
authors.affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Viral Hepatitis Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Ciccaglione
mesh_terms: D000328:Adult; D016000:Cluster Analysis; D019143:Evolution, Molecular; D005260:Female; D005838:Genotype; D006509:Hepatitis B / Q000453:epidemiology / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000235:genetics; D006515:Hepatitis B virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014416:Tunisia / Q000453:epidemiology; D055815:Young Adult
chemical_list: D006514:Hepatitis B Surface Antigens
keywords: epidemiology; evolution; hepatitis B virus