Human Immunodeficiency Virus Type 1 (HIV-1) Subtype B Epidemic in Panama Is Mainly Driven by Dissemination of Country-Specific Clades

Abstract

The Human immunodeficiency virus type-1 (HIV-1) subtype B is the most predominant clade in Central America; but information about the evolutionary history of this virus in this geographic region is scarce. In this study, we reconstructed the spatiotemporal and population dynamics of the HIV-1 subtype B epidemic in Panama. A total of 761 HIV-1 subtype B pol sequences obtained in Panama between 2004 and 2013 were combined with subtype B pol sequences from the Americas and Europe. Maximum Likelihood phylogenetic analyses revealed that HIV-1 subtype B infections in Panama derived from the dissemination of multiple founder viruses. Most Panamanian subtype B viruses (94.5%) belong to the pandemic viral strain proposed as originated in the US, whereas others (5.5%) were intermixed among non-pandemic Caribbean strains. The bulk (76.6%) of subtype B sequences from Panama grouped within 12 country-specific clades that were not detected in other Central American countries. Bayesian coalescent-based analyses suggest that most Panamanian clades probably originated between the early 1970s and the early 1980s. The root location of major Panamanian clades was traced to the most densely populated districts of Panama province. Major Panamanian clades appear to have experienced one or two periods of exponential growth of variable duration between the 1970s and the 2000s, with median growth rates from 0.2 to 0.4 year− 1. Thus, the HIV-1 subtype B epidemic in Panama is driven by the expansion of local viral strains that were introduced from the Caribbean and other American countries at an early stage of the AIDS pandemic.

Spatiotemporal Dynamics of Dissemination of Non-Pandemic HIV-1 Subtype B Clades in the Caribbean Region

“…This reconstructed demographic pattern fully agrees with the epidemiological profile of the Caribbean region, where the number of people living with HIV has remained relatively stable since the late 1990s [1], [6], and resemble the patterns previously described for subtype B epidemics in other American countries including Brazil [74] the US [75] and Panama [25]. Interestingly, the mean growth rates estimated for the B CAR clades from Hispaniola, Jamaica and Trinidad and Tobago (0.35–0.45 year −1 ) were similar to those estimated for B PANDEMIC clades mainly circulating among heterosexual populations from Panama (0.20–0.40 year −1 ) [25]; but lower than those estimated for B PANDEMIC clades mainly transmitted among MSM populations from Cuba, Italy, Hong Kong and the United Kingdom (0.5–1.6 year −1 ) [24], [38], [39], [40]. This suggests that ecological factors, rather than viral lineage characteristics, are the major determinants of the HIV-1 subtype B epidemic growth rate across different countries.…”

Identification of major routes of HIV transmission throughout Mesoamerica

“…Interestingly, even with this increase in immigration, the main spread of the Panamanian epidemic seems to remain national with Panama not representing a significant source of seeding of other regional epidemics. This is consistent with recently published work suggesting a recent intra-national spread of Panamanian clades with little overlap with other Central American countries (48, 49), although it is important to acknowledge that most of the Panamanian sequences included in this study were obtained from individuals residing in the central districts, which could limit detection of other possible connections.…”

“…Spread of HIV between nations was then in part shaped by patterns of travel and economic migration that have occurred in the region. Eventually, after seeding at-risk populations across the region, our data and that from others (48, 49) suggest that these epidemics then evolved regionally, with limited mixing across nations, and risk groups.…”

“…In Panama, the epidemic is known to be concentrated along the economic corridor of the Panama Canal, including the central districts of San Miguelito and Panama (which includes Panama City) (48). As an internationally important economic zone, an increase in migration of workers, businessmen and executives, mainly from Guatemala and Mexico to Panama for business reasons has been reported during recent years (48, 56). In addition to tourism, this could explain the inclusion of Guatemalan and Panamanian MSM in many international clusters observed in this study.…”

Molecular epidemiology of HIV-1 in Iceland: Early introductions, transmission dynamics and recent outbreaks among injection drug users

“…The molecular epidemiology of HIV-1 has been studied extensively both globally, (Faria et al, 2014;Wertheim et al, 2014) and in limited geographic settings, (Aldous et al, 2012;Bruhn et al, 2014;Ciccozzi et al, 2013;Esbjornsson et al, 2016;Kouyos et al, 2010;Mendoza et al, 2014;Paraskevis et al, 2015) to increase the understanding of the drivers of HIV-1 transmission and to increase the focus of preventive strategies (Brenner et al, 2013).…”