A connectivity model for assessment of HIV transmission risk in injection drug users (IDUs).

The purpose of this study was to produce models composed of mapping of connectivity networks of HIV transmission risk in injection drug users (IDUs). This methodology provided a novel approach and diagnostic tool for understanding HIV infection transmission risk and drug use in the typical niche of IDUs, i.e., a "shooting gallery" (a gathering site for injection drug activity). Furthermore, component IDUs may have memberships in multiple "shooting galleries" revealing subsequent interconnectivities. Charting of IDU connectivity diagrams illustrated the relationships of peripheral sites to the critical central core of high HIV transmission risk. Members of this highly interlinked and infectious central core of IDUs had high HIV transmission risk and severe drug use-producing high morbidity and mortality that resulted in great public health concern. In addition, connectivity diagrams reveal very high HIV transmission risk in component IDUs in "dual memberships", i.e., membership in more than one central core (with the highest number of partners). Therefore, IDUs with "dual memberships" were the most infectious members of the "shooting gallery". In summation, network mapping of HIV transmission risk in IDUs allows for subsequent socio-behavioral analysis and the development of focused individual and programmatic interventions.