Resumen
Central America has some of the highest HIV infection rates in the hemisphere. The association between transportation corridors, trade, migration and HIV transmission has been well-documented in other settings. Here, using molecular epidemiologic techniques, we inferred putative clustering of HIV infected individuals sampled from across Mesoamerica, and estimated patterns of viral migration. 6,092 HIV-1 subtype B partial pol sequences sampled from unique individuals from Mexico (40.7%), Guatemala (24.4%), Honduras (19%), Panama (8.2%), Nicaragua (5.5%), Belize (1.4%) and El Salvador (0.7%) between 2011-2016 were included. Phylogenetic and genetic network analyses were performed to infer putative relationships between HIV sequences. The demographic and geographic associations with clustering were analyzed and plotted using ArcGIS v.10.1 (ESRI, Redlands, CA). Viral migration patterns were inferred using the Slatkin-Maddison approach on 100 iterations of random subsets of equal number of sequences per location. Time to the most common recent ancestor (tMRCA) of the largest clusters were inferred with a Bayesian approach using the BEAST software package. A total of 1,959/6,092 (22.2%) of sequences demonstrated putative linkage with at least one other sequence, forming 682 transmission clusters, [range: 2-89 individuals]. Clustering individuals were significantly more likely to be younger (median age 30 vs 33 years, p<0.01) and men who have sex with men (38.7% vs 30.4%, p<0.01). Sequences from Guatemala (p<0.01) and Nicaragua (p=0.02) were significantly more likely to cluster. Of the 682 clusters, 34 (5%) included sequences from multiple countries with commonly observed linkages between Mexican and Honduran sequences (Fig.1). Eight of the 682 clusters included more than 10 individuals. These included two clusters with individuals exclusively from Guatemala, comprised of 52 and 89 individuals with a tMRCA of 1993 and 2004 respectively. Viral migration analyses showed that the Central and Southern regions of Mexico and Belize were the major source of HIV throughout the region (p<0.01). We also found evidence of significant major routes of viral migration between regions within Mexico. International clusters were infrequent, suggesting moderate intermix between HIV epidemics of the different Mesoamerican countries. Nevertheless, we observed important sources of transnational HIV spread in the region, including Southern and Central Mexico, and Belize.