You forgot another primary vector....bi-sexual men and prostitutes.     Many of whom are found near gambling locations.  

I once did a Request for Proposals for DHS to seek ways to reduce HIV.  One of the proposals I got was to get a $50,000 grant to teach prostitutes how to put condoms on their customers.  They proposed to instruct 250 Portland area prostitutes.  That would have been $200.00 per prostitute.  

We gave the grant to someone else.