As the Brazilian economic crisis got worse in the 1980s thousands of people started to collect waste from the streets and disposal areas and sold it to recycling mills. In Brazil it is estimated that the number of recyclable waste collectors increased from 150000 in 1999 to 500000 in 2004. An important aspect characterizing this vulnerable group is the fact that most preventive policies related to sexually transmitted infections are aimed at groups and populations more exposed to them but excluding the marginal group of street dwellers like the great majority of waste collectors. This work follows a long line of research dealing with HIV transmission dynamics in socially vulnerable communities of Brazil. (excerpt)