Title: The Use of Social Network Analysis to Quantify the Importance of Social Venues in an Infectious Syphilis Outbreak in Calgary, Alberta: A pilot study
Objective: Places where people meet sex partners may play an important role in the transmission of sexually transmitted infections. The primary research objective of this network survey study was to explore the use of social network analysis as an epidemiological tool to determine the relative importance of venues where people meet sex partners to the transmission of infectious syphilis.
Methods: During routine public health measures of infectious disease control, cases and named contacts of infectious syphilis, aged 18-75 years were identified and enrolled at an Alberta Sexually Transmitted Disease clinic, between April-August, 2009. In addition to standard contact tracing information, participants were asked to list all venues attended in the last six months where sexual partnering occurred. Sexual affiliation networks were constructed by linking individuals to sex partner meeting venues. Graph-theoretic algebraic calculations of network position and permutation statistical methods were used to determine what type of venue connected the most individuals infected with syphilis.
Results: A total of 154 network members comprised of 46 cases of infectious syphilis and 108 named sexual contacts were identified in the sexual affiliation networks. A densely connected network of 94 gay men linked together by 21 venues was identified. In this sexual affiliation network, Internet venues had significantly higher degree centrality than non-internet venues (p<0.05). The three most central Internet venues, connected two thirds of all infectious syphilis cases in the network.
Conclusion: Network analysis identified key venues that connected individuals who were infected with syphilis. These venues could provide public health officials with an epidemiologic target for prevention and intervention strategies to prevent further dissemination of disease.
