Combining social and genetic networks to study HIV transmission in mixing risk groups

Reconstruction of HIV transmission networks is important
for understanding and preventing the spread of the virus and drug resistant
variants. Mixing risk groups is important in network analysis
of HIV in order to assess the role of transmission between risk groups
in the HIV epidemic. Most of the research focuses on the transmission
within HIV risk groups, while transmission between different risk
groups has been less studied.We use a proposed filter-reduction method
to infer hypothetical transmission networks of HIV by combining data
from social and genetic scales.We modified the filtering process in order
to include mixing risk groups in the model. For this, we use the information
on phylogenetic clusters obtained through phylogenetic analysis. A
probability matrix is also defined to specify contact rates between individuals
form the same and different risk groups. The method converts
the data form each scale into network forms and combines them by
overlaying and computing their intersection. We apply this method to
reconstruct networks of HIV infected patients in central Italy, including
mixing between risk groups. Our results suggests that bisexual behavior
among Italian MSM and IDU partnership are relatively important
in heterosexual transmission of HIV in central Italy.