Origin and Population Dynamics of a Novel HIV-1 Subtype G Clade Circulating in Cape Verde and Portugal

Abstract

The human immunodeficiency virus type 1 (HIV-1) subtype G is the most prevalent and second most prevalent HIV-1 clade in Cape Verde and Portugal, respectively; but there is no information about the origin and spatiotemporal dispersal pattern of this HIV-1 clade circulating in those countries. To this end, we used Maximum Likelihood and Bayesian coalescent-based methods to analyze a collection of 578 HIV-1 subtype G pol sequences sampled throughout Portugal, Cape Verde and 11 other countries from West and Central Africa over a period of 22 years (1992 to 2013). Our analyses indicate that most subtype G sequences from Cape Verde (80%) and Portugal (95%) branched together in a distinct monophyletic cluster (here called GCV-PT). The GCV-PT clade probably emerged after a single migration of the virus out of Central Africa into Cape Verde between the late 1970s and the middle 1980s, followed by a rapid dissemination to Portugal a couple of years later. Reconstruction of the demographic history of the GCV-PT clade circulating in Cape Verde and Portugal indicates that this viral clade displayed an initial phase of exponential growth during the 1980s and 1990s, followed by a decline in growth rate since the early 2000s. Our data also indicate that during the exponential growth phase the GCV-PT clade recombined with a preexisting subtype B viral strain circulating in Portugal, originating the CRF14_BG clade that was later disseminated to Spain and Cape Verde. Historical and recent human population movements between Angola, Cape Verde and Portugal probably played a key role in the origin and dispersal of the GCV-PT and CRF14_BG clades.

Genetic Characterization of a New HIV-1 Sub-Subtype A in Cabo Verde, Denominated A8

“…The high diversity of HIV-1 described in Cabo Verde may be related to its proximity and relationships with West Africa and European countries. Studies already conducted show strong similarity to the HIV-1 subtype G between sequences from Portugal and Cabo Verde and propose that historical and recent movements between Angola, Cabo Verde, and Portugal may have played a key role in the origin and dispersion of certain viral clades [24]. Due to its geographical location and investment in tourism, Cabo Verde receives thousands of tourists from all continents, especially Europe.…”

Molecular Epidemiology of HIV-1 Subtype G in the Russian Federation

“…According to an analysis on the spread of the HIV-1 from Africa to Europe, a centre of infection has emerged in the south of Europe and includes Spain and Portugal [12,34]. The clustering of 8 Russian recombinant genomes with those from Spain and Portugal can date back to 1984 [95% HPD: 1971–1992] and neighbours adjacent to this branch from Cuba can date back to 1988 [95% HPD: 1977–1993].…”

“…However, worldwide, subtype G is the sixth most prevalent HIV-1 clade and accounts for nearly 5% of all global infections. This subtype reaches its highest prevalence in some African countries, comprising 5–50% of HIV-1 infections [12]. Some subtype G strains have also disseminated out of the African continent.…”

“…Some subtype G strains have also disseminated out of the African continent. The most remarkable example is Portugal, where subtype G is the second most prevalent HIV-1 clade (>10%), after subtype B (>40%) [12,13,14]. In addition to Portugal, Spain has experienced an enormous spread of HIV; their epidemics are characterized by substantial viral diversity and distinct molecular properties compared to other European countries [15,16,17].…”