In the past year, public health authorities in Ciudad Sandino, Nicaragua have begun using dump trucks and megaphones to stop the spread of dengue fever. In targeted campaigns, doctors, garbage collectors, and community members exhort homeowners to discard the piles of garbage in their homes. They warn that dengue-carrying mosquitoes breed in the pools of rainwater that form in these piles, adding that there is neither a cure nor an effective vaccine for dengue. The anti-dengue campaigns have brought waste and the urban landscape to the forefront of local health discourse. But although they were conceived by local people, the campaigns have not created a consensus among the residents about how to stop dengue from spreading. Instead, they have aggravated social divisions among health workers, city garbage collectors, and the garbage scavengers who survive by collecting items in streets and neighborhood dumps and selling them to recycling companies. These divisions have arisen not over how to define disease, but over how to foster community participation in public health, how to manage space, and how to balance resources and hazards on the landscape. In short, they are about the human role in disease ecology. Halting the spread of infectious diseases is now a major international health priority, but there exist few studies of how people in marginalized urban communities exchange and deploy knowledge about these diseases. My study of waste management in Ciudad Sandino will ask how actors explain disease ecology by drawing not only on biomedical categories but also on everyday experiences with dengue in the landscape. This research will provide a practice-based study of how citizens blend biomedical and experiential knowledge into historically and politically situated disease ecologies.