Increasing prevalence of HIV-1 subtype A in Greece: estimating epidemic history and origin.
BACKGROUND
In North America and Europe, human immunodeficiency virus (HIV)-1 infection has typically been dominated by subtype B transmission. More recently, however, non-B subtypes have been increasingly reported in Europe.


METHODS
We analyzed 1158 HIV-1-infected individuals in Greece by DNA sequencing and phylogenetic analyses of protease and partial reverse-transcriptase regions.


RESULTS
We found that the prevalence of non-B subtypes has increased over time and that this significant trend can be mainly attributed to subtype A, which eventually surpassed subtype B in prevalence in 2004 (42% and 33%, respectively). Multivariate analysis revealed that the year of HIV diagnosis was independently associated with subtype A infection (odds ratio for being infected with subtype A for a 10-year increase in the time period of diagnosis, 2.09 [95% confidence interval, 1.36-3.24]; P<.001). Phylogenetic analysis revealed that the subtype A epidemic in Greece is the result of a single founder event. The date of the most recent common ancestor of the subtype A in Greece was estimated to be 1977.9 (95% highest posterior density interval, 1973.7-1981.9).


CONCLUSIONS
Subtype A circulates among the long-term residents of Greece. This is in contrast to the situation in most European countries, in which infection with non-B genetic forms is associated either with being an immigrant or heterosexual or with intravenous drug use.
Paraskevis
Dimitrios
D
Department of Hygiene and Epidemiology, National Retrovirus Reference Center, Athens, Greece.
Magiorkinis
Emmanouil
E
Magiorkinis
Gkikas
G
Sypsa
Vana
V
Paparizos
Vassilios
V
Lazanas
Marios
M
Gargalianos
Panagiotis
P
Antoniadou
Anastasia
A
Panos
Georgios
G
Chrysos
Georgios
G
Sambatakou
Helen
H
Karafoulidou
Anastasia
A
Skoutelis
Athanasios
A
Kordossis
Theodoros
T
Koratzanis
Georgios
G
Theodoridou
Maria
M
Daikos
Georgios L
GL
Nikolopoulos
Georgios
G
Pybus
Oliver G
OG
Hatzakis
Angelos
A
D000328:Adult; D005260:Female; D014644:Genetic Variation; D006115:Greece / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology / Q000235:genetics*; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D015995:Prevalence
D054303:HIV Reverse Transcriptase; D016333:HIV Protease