HIV-1 non-B infections have been increasing in Europe for several years. In Germany, subtype A belongs to the most abundant non-B subtypes showing an increasing prevalence of 8.3% among new infections in 2016. Here we trace the origin and examine the current spread of the German HIV-1 subtype A epidemic. Bayesian coalescence and birth-death analyses were performed with 180 German HIV-1 pol sequences and 528 related and publicly available sequences to reconstruct the population dynamics and fluctuations for each of the transmission groups. Our reconstructions indicate two distinct sources of the German subtype A epidemic, with an Eastern European and an Eastern African lineage both cocirculating in the country. A total of 13 German-origin clusters were identified; among these, 6 clusters showed recent activity. Introductions leading to further countrywide spread originated predominantly from Eastern Africa when introduced before 2005. Since 2005, however, spreading introductions have occurred exclusively within the Eastern European clade. Moreover, we observed changes in the main route of subtype A transmission. The beginning of the German epidemic (1985 to 1995) was dominated by heterosexual transmission of the Eastern African lineage. Since 2005, transmissions among German men who have sex with men (MSM) have been increasing and have been associated with the Eastern European lineage. Infections among people who inject drugs dominated between 1998 and 2005. Our findings on HIV-1 subtype A infections provide new insights into the spread of this virus and extend the understanding of the HIV epidemic in Germany.IMPORTANCE HIV-1 subtype A is the second most prevalent subtype worldwide, with a high prevalence in Eastern Africa and Eastern Europe. However, an increase of non-B infections, including subtype A infections, has been observed in Germany and other European countries. There has simultaneously been an increased flow of refugees into Europe and especially into Germany, raising the question of whether the surge in non-B infections resulted from this increased immigration or whether German transmission chains are mainly involved. This study is the first comprehensive subtype A study from a western European country analyzing in detail its phylogenetic origin, the impact of various transmission routes, and its current spread. The results and conclusions presented provide new and substantial insights for virologists, epidemiologists, and the general public health sector. In this regard, they should be useful to those authorities responsible for developing public health intervention strategies to combat the further spread of HIV/AIDS.

中文翻译：

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在德国重建遗传史和目前HIV-1亚型的传播。

在欧洲，HIV-1非B型感染已增加了几年。在德国，A型亚型属于最丰富的非B型亚型，在2016年的新感染中患病率上升8.3％。在这里，我们追踪起源并检查了德国HIV-1 A型亚型流行病的当前传播情况。用180条德国HIV-1 pol序列和528条相关的和公开可用的序列进行贝叶斯合并和出生死亡分析，以重构每个传播群体的种群动态和波动。我们的重建工作表明，德国A型流行病有两个不同的来源，东欧和东部非洲血统在该国共同流行。总共发现了13个德国起源的集群；其中，有6个集群显示近期活动。导致进一步全国范围传播的引种主要是在2005年之前从东部非洲起源的。然而，自2005年以来，传播引种只发生在东欧进化枝内。此外，我们观察到了亚型传播的主要途径的变化。德国流行病的开始（1985年至1995年）主要是东非血统的异性传播。自2005年以来，与男性发生性关系（MSM）的德国男性之间的传播一直在增加，并与东欧血统相关。在1998年至2005年期间，注射吸毒者中的感染占主导地位。我们对HIV-1 A型亚型感染的发现提供了对该病毒传播的新见解，并扩展了人们对德国HIV流行的认识。重要信息HIV-1 A亚型是全球第二流行的亚型，在东部非洲和东欧的患病率很高。但是，在德国和其他欧洲国家，非B型感染（包括A型亚型）的感染有所增加。同时，有越来越多的难民涌入欧洲，尤其是流向德国，这引发了这样一个问题：非B感染的激增是由于移民的增加所导致，还是主要涉及德国的传播链。这项研究是西欧国家进行的第一项全面的A型亚型研究，详细分析了其系统发生起源，各种传播途径的影响及其当前传播。提出的结果和结论为病毒学家，流行病学家，以及一般公共卫生部门。在这方面，它们应对负责制定公共卫生干预策略以对抗艾滋病毒/艾滋病进一步蔓延的那些机构有用。