Fig. 1.

The densely populated urban slum dwellers of Pau da Lima in Salvador, Brazil, reside in a heterogeneous landscape demarcated by steep slopes and valleys (panel 1A). Track plates were placed near the valley floor where open sewers (1B), poorly constructed houses and limited sanitation services provide abundant resources for Norway rats (1C). Rat signs, including paw prints, tail slides and scratching are readily visible on a track plate (1D) and were scored for activity/abundance metrics