Responds to the articles by Grassley, et al, Lowndes et al, and Saidel et al (see records 2003-02937-004, 2003-02937-005, 2003-02937-006) which examine the transmission of HIV from injecting drug users (IDUs) to non-injecting sexual partners and its influence on larger scale epidemics. The current author discusses the role mathematical modeling can play in describing and understanding complex patterns of HIV infection and in providing insights into the role of IDU and other vulnerable populations in enhancing and potentially sustaining a more generalised epidemic. The article highlights the importance of effective interventions aimed at reducing simultaneously reducing injecting and sexual risk among IDUs and sex workers at all points of a general epidemic so that the potential for the bridging of HIV infections is reduced. (PsycINFO Database Record (c) 2003 APA, all rights reserved)
