Assessment of Overlap of Phylogenetic Transmission Clusters and Communities in Simple Sexual Contact Networks: Applications to HIV-1

• Published in: PloS one Vol. 11; no. 2; p. e0148459
• Main Authors: Villandre, Luc, Stephens, David A., Labbe, Aurelie, Günthard, Huldrych F., Kouyos, Roger, Stadler, Tanja
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.02.2016; Public Library of Science (PLoS)
• Subjects: Acquired immune deficiency syndrome; Adult; AIDS; Algorithms; Bioinformatics; Biology and Life Sciences; Care and treatment; Cluster Analysis; Clusters; Communities; Community Networks - statistics & numerical data; Computer and Information Sciences; Computer Simulation; Development and progression; Disease transmission; Epidemics; Epidemics - prevention & control; Epidemiology; Genotype; Graphs; Health aspects; HIV; HIV Infections - epidemiology; HIV Infections - psychology; HIV Infections - transmission; HIV Infections - virology; HIV-1 - classification; HIV-1 - genetics; Homosexuality, Male; Hospitals; Human immunodeficiency virus; Humans; Incidence; Infections; Infectious diseases; Islands; Male; Medicine and health sciences; Middle Aged; Models, Statistical; Networks; Occupational health; Phylogenetics; Phylogeny; Research and Analysis Methods; Residence Characteristics - statistics & numerical data; Risk factors; Sexual Partners; Sexually transmitted diseases; STD; Switzerland - epidemiology; Virology; Switzerland; United States
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0148459

Transmission patterns of sexually-transmitted infections (STIs) could relate to the structure of the underlying sexual contact network, whose features are therefore of interest to clinicians. Conventionally, we represent sexual contacts in a population with a graph, that can reveal the existence of communities. Phylogenetic methods help infer the history of an epidemic and incidentally, may help detecting communities. In particular, phylogenetic analyses of HIV-1 epidemics among men who have sex with men (MSM) have revealed the existence of large transmission clusters, possibly resulting from within-community transmissions. Past studies have explored the association between contact networks and phylogenies, including transmission clusters, producing conflicting conclusions about whether network features significantly affect observed transmission history. As far as we know however, none of them thoroughly investigated the role of communities, defined with respect to the network graph, in the observation of clusters. The present study investigates, through simulations, community detection from phylogenies. We simulate a large number of epidemics over both unweighted and weighted, undirected random interconnected-islands networks, with islands corresponding to communities. We use weighting to modulate distance between islands. We translate each epidemic into a phylogeny, that lets us partition our samples of infected subjects into transmission clusters, based on several common definitions from the literature. We measure similarity between subjects' island membership indices and transmission cluster membership indices with the adjusted Rand index. Analyses reveal modest mean correspondence between communities in graphs and phylogenetic transmission clusters. We conclude that common methods often have limited success in detecting contact network communities from phylogenies. The rarely-fulfilled requirement that network communities correspond to clades in the phylogeny is their main drawback. Understanding the link between transmission clusters and communities in sexual contact networks could help inform policymaking to curb HIV incidence in MSMs.