New insights into the hepatitis E virus genotype 3 phylodynamics and evolutionary history.
Hepatitis E virus (HEV) is an emergent hepatotropic virus endemic mainly in Asia and other developing areas. However, in the last decade it has been increasingly reported in high-income countries. Human infecting HEV strains are currently classified into four genotypes (1-4). Genotype 3 (HEV-3) is the prevalent virus genotype and the mostly associated with autochthonous and sporadic cases of HEV in developed areas. The evolutionary history of HEV worldwide remains largely unknown. In this study we reconstructed the spatiotemporal and population dynamics of HEV-3 at global scale, but with particular emphasis in South America, where case reports have increased dramatically in the last years. To achieve this, we applied a Bayesian coalescent-based approach to a comprehensive data set comprising 97 GenBank HEV-3 sequences for which the location and sampling date was documented. Our phylogenetic analyses suggest that the worldwide genetic diversity of HEV-3 can be grouped into two main Clades (I and II) with a Ƭmrca dated in approximately 320years ago (95% HPD: 420-236years) and that a unique independent introduction of HEV-3 seems to have occurred in Uruguay, where most of the human HEV cases in South America have been described. The phylodynamic inference indicates that the population size of this virus suffered substantial temporal variations after the second half of the 20th century. In this sense and conversely to what is postulated to date, we suggest that the worldwide effective population size of HEV-3 is not decreasing and that frequently sources of error in its estimates stem from assumptions that the analyzed sequences are derived from a single panmictic population. Novel insights on the global population dynamics of HEV are given. Additionally, this work constitutes an attempt to further describe in a Bayesian coalescent framework, the phylodynamics and evolutionary history of HEV-3 in the South American region.
Sección Virología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
Santiago
S
Mirazo
Laboratorio de AIDS & Imunologia Molecular, Instituto Oswaldo Cruz. Av. Brasil 4365, 21045900 Rio de Janeiro, Brazil.
Daiana
D
Mir
Laboratorio de AIDS & Imunologia Molecular, Instituto Oswaldo Cruz. Av. Brasil 4365, 21045900 Rio de Janeiro, Brazil.
Gonzalo
G
Bello
Sección Virología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
Natalia
N
Ramos
Laboratorio de Organización y Evolución del Genoma, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400. Montevideo, Uruguay.
Héctor
H
Musto
Sección Virología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay. Electronic address: jarbiza@fcien.edu.uy.
Juan
J
Arbiza
D001499:Bayes Theorem; D005075:Biological Evolution; D014644:Genetic Variation; D005838:Genotype; D016751:Hepatitis E / Q000453:epidemiology* / Q000821:virology; D016752:Hepatitis E virus / Q000145:classification / Q000235:genetics*; D006801:Humans; D009010:Monte Carlo Method; D010802:Phylogeny; D058974:Phylogeography; D011157:Population Dynamics; D013020:South America / Q000453:epidemiology; D013997:Time Factors
Evolutionary history; Hepatitis E virus genotype 3 phylodynamics; South America