engleski

The global spread of HIV-1 CRF01_AE epidemics: a phylogeographic analysis

Background: HIV-1 CRF01_AE originated in West-Central Africa and then migrated to Thailand where it established a major epidemic. Currently CRF01_AE is present mainly in South-East and East Asia and at lower frequencies in Europe and North America Methods: We assembled a global dataset of 2, 736 CRF01_AE sequences by pooling sequences from online database repositories, and from patient-cohort studies. We estimated viral dispersal patterns using statistical phylogeography run over a set of bootstrap trees estimated by the maximum likelihood (ML) method. Results: Phylogeographic analysis showed that Thai sequences are highly dispersed across the global tree, whereas viral sequences from China and Vietnam form large monophyletic clusters. Indeed, Thailand was the source of viral dispersal to most areas worldwide including 17 out of 20 sampled countries in Europe, North America and Asia. In turn Thailand imported the CRF01_AE from Africa only. Japan also contributes significantly to the global viral mobility but to a lesser extent than Thailand. Singapore, Vietnam and other Asian countries play a minor role in viral dissemination as they interact with a small number of countries mainly in Asia and Europe. On the other hand, China and Taiwan are viral migration targets, importing infections from neighboring Asian countries, North America and Africa. Within Europe, Sweden exported viral strains to the Netherlands, Norway, Russia and Finland. Notably, 29.7% and 11.6% of patients in Europe reported to have a Thai and Vietnamese origin, respectively. Notably, 70.7% of those infected with CRF01_AE in Europe were heterosexuals. Conclusions: Global spread of CRF01_AE epidemic has followed a very distinctive pattern in comparison with subtype B, where Thailand has played a central role. This might be explained first by the fact that Thailand is an attractive touristic destination for Europeans and Americans and, second by substantial Thai emigration to Western world.

HIV-1; CRF01_AE

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