Phylogenetic Analysis of Human Immunodeficiency Virus Type 2 Group B.
BACKGROUND
Human immunodeficiency virus type 2 (HIV-2) infections are mainly restricted to West Africa; however, in the recent years, the prevalence of HIV-2 is a growing concern in some European countries and the Southwestern region of India. Despite the presence of different HIV-2 groups, only A and B Groups have established human-to-human transmission chains.


OBJECTIVE
This work aimed to evaluate the phylogeographic inference of HIV-2 Group B worldwide to estimate their data of origin and the population dynamics.


METHODS
The evolutionary rates, the demographic history for HIV-2 Group B dataset, and the phylogeographic analysis were estimated using a Bayesian approach. The viral gene flow analysis was used to count viral gene out/in flow among different locations.


RESULTS
The root of the Bayesian maximum clade credibility tree of HIV-2 Group B dated back to 1957. The demographic history of HIV-2 Group B showed that the epidemic remained constant up to 1970 when started an exponential growth. From 1985 to early 2000s, the epidemic reached a plateau, and then it was characterized by two bottlenecks and a new plateau at the end of 2000s. Phylogeographic reconstruction showed that the most probable location for the root of the tree was Ghana. Regarding the viral gene flow of HIV-2 Group B, the only observed viral gene flow was from Africa to France, Belgium, and Luxembourg.


CONCLUSIONS
The study gives insights into the origin, history, and phylogeography of HIV-2 Group B epidemic. The growing number of infections of HIV-2 worldwide indicates the need for strengthening surveillance.
Department of Infectious, Parasitic and Immunomediated Diseases, National Institute of Health, Rome, Italy; Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
Eleonora
E
Cella
Department of Infectious, Parasitic and Immunomediated Diseases, National Institute of Health, Rome, Italy.
Alessandra
A
Lo Presti
Department of Infectious, Parasitic and Immunomediated Diseases, National Institute of Health, Rome, Italy; Department of Biology, General Pathology Laboratory, University of Rome Tor Vergata, Rome, Italy.
Marta
M
Giovanetti
Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Milan, Italy.
Carla
C
Veo
Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Milan, Italy.
Alessia
A
Lai
Clinical Pathology and Microbiology Laboratory, University Hospital Campus Bio-Medico of Rome, Rome, Italy.
Giordano
G
Dicuonzo
Clinical Pathology and Microbiology Laboratory, University Hospital Campus Bio-Medico of Rome, Rome, Italy.
Silvia
S
Angeletti
Laboratory of Molecular Virology, Tor Vergata Foundation Hospital, Rome, Italy.
Marco
M
Ciotti
Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Milan, Italy.
Gianguglielmo
G
Zehender
Department of Infectious, Parasitic and Immunomediated Diseases, National Institute of Health, Rome, Italy; Clinical Pathology and Microbiology Laboratory, University Hospital Campus Bio-Medico, Rome, Italy.
Massimo
M
Ciccozzi
Evolution; Group B; human immunodeficiency virus type 2; phylogeny; phylogeographic analysis