Ph.D. Proposal Defense: “Complex Multi-Agent Simulation of MSM HIV Transmission For Examining Concurrency”, Robert Puckett

Robert Puckett will be presenting his dissertation proposal on Friday, December 13, at 12noon in POST 318B (note the room is not the usual conference room).

Complex Multi-Agent Simulation of MSM HIV Transmission For Examining Concurrency

Abstract: The Human Immunodeficiency Virus (HIV) is a complex virus with a high rate of death, several modes of transmission, and long asymptomatic incubation period. Over time the virus weakens the host’s immune system leading to Acquired Immune Deficiency Syndrome (AIDS). Once progressed to AIDS, a body becomes susceptible to a range of opportunistic infections and cancers. In developed countries, HIV disproportionately affects men who have sex with men (MSM), primarily due to the practice of unprotected anal receptive (UAR) sex. Epidemic modeling helps researchers in developing hypotheses on the driving forces, testing intervention strategies, and predicting the course of the HIV epidemic. Although many models for HIV have been developed, HIV remains a difficult subject to model owing to complex transmission modes, limitations in data collection, and variability in human behavior. Instead of studying populations in aggregate, microsimulation techniques allow for the study of individuals over time. A multi-agent system (MAS) can be used to implement a microsimulation of HIV transmission among individual people existing within a complex network of sexual partners. Through simple rules governing agent interactions, complex behavior can emerge from the society of agents.

Of particular interest for study, the role of concurrent relationships as a driving force of epidemics has become a hotly debated topic in recent years. To reduce conflicting definitions in research and data collection, UNAIDS has formally defined concurrency as “overlapping sexual partnerships where sexual intercourse with one partner occurs between two acts of intercourse with another partner.” In 1998, Morris and Kretzschmar concluded from stochastic simulations that concurrent partnerships “dramatically increase the speed and pervasiveness of the epidemic spread.” Numerous subsequent publications by various authors have argued for and against the degree of impact for concurrency in HIV epidemics around the world. Thus, the role of concurrency is far from a settled subject.

In our research, we build and examine a multi-agent simulation of HIV transmission via concurrent relationships in a MSM community. Our simulation will illuminate some of the behavioral factors and sexual network characteristics that contribute to the spread of HIV. Principally, we believe that we will observe a profound impact from the acute HIV infection phase interacting with concurrent relationships to produce significantly larger epidemics. Insights gained from our simulation will aid policy makers in developing more useful HIV surveillance methods and intervention strategies.

Dissertation committee: Nancy Reed (chair), Tim Brown, JB Nation, Luz Quiroga, and Dennis Streveler