A cave small world network model for HIV transmission among drug users sharing syringe

Injecting drug users (IDU) sharing syringe is a major mode of Human Immunodeficiency Virus (HIV) transmission. Intervention Measures such as voluntary counseling and HIV testing, free syringe exchange programs and free antiretroviral treatment (ART) play important role in IDU HIV transmission dynamics and success of prevention. This paper presents a Cave Small World agent network model for simulating the interaction and evolution of IDU individual behaviors, IDU networks and HIV prevention interventions. A Cave Small World agent network is a social network with community structure. This network is composed of many small IDU subgroups, and agents in the same group are strongly connected while the connections between different subgroups are weak. The model can well reproduce the main characteristics of IDU network. Each individual agent on network has his own specified information and rules to react to HIV prevention interventions. Exploratory simulation results are consistent with empirical studies demonstrating that the effectiveness of a combination of interventions, including voluntary counseling and HIV testing, free syringe exchange programs and ART. Our model can be used to identify potential collective benefits of combination prevention interventions for IDU HIV transmission.