CNH2-S: Impacts of Urban Rats and Rodent Control on Public Health and Urban Wildlife Conservation

Lincoln Park Zoo, Chicago IL

Investigators

Abstract

Human societies have lived in conflict with rats for thousands of years. Brown rats (Rattus norvegicus) can carry several diseases shared with humans, known as rat-associated zoonoses, such as leptospirosis, Seoul hantavirus, and bubonic plague. Rats also cause billions of dollars in property damage annually. In addition to physical health risks, chronic exposure to rats and their associated property damage can act as a mental health stressor for residents. A better understanding of what processes increase the risk of disease and mental health impacts from living with rats will help improve public health in cities around the world. While little is known about urban rats, the risks associated with rat infestations are often disproportionately high for low-income communities, likely due to fewer resources to maintain infrastructure and control rodent populations. Income disparities between neighborhoods is especially pervasive in Chicago, Illinois, the city with the most rat complaints per capita in the United States. This combination of high rat encounter rates and income disparities in Chicago likely creates further inequities in resident exposure to rats and disease risk. Frequent negative experiences with rats may also influence resident attitudes toward other species of urban wildlife. For example, strong negative attitudes about rats may be associated with negative attitudes about similar native species such as squirrels. Understanding the relationships between human attitudes about rats and other wildlife will help to mitigate any eroding effects of wildlife pests on public support for urban nature conservation. The aim of this award is to understand how to mitigate public health risks from rats and advance urban conservation by studying the interactions between urban residents and brown rats (Rattus norvegicus). The specific project goals are to: 1) quantify the impacts of rat infestations on the physical and mental health, attitudes, and approaches to pest control of socioeconomically diverse urban residents; and 2) quantify the impacts of pest control initiatives on rat population dynamics, rat disease ecology, and urban predator health. To achieve these objectives, the research will integrate data on rats, predators (i.e. cats), and residents in Chicago neighborhoods that vary in household income. Interviews and surveys will be used to collect data on resident experiences with rats, mental and physical health, and attitudes about rats and other urban wildlife species. In the same blocks, citizen scientists will trap rats and collect fecal samples from free-living cats. This data will be used to relate local rat abundance and rates of infection with corresponding resident experiences and attitudes about rats. Local rates of rat infection will be evaluated with respect to resident experiences with zoonotic pathways such as being exposed to rat feces or urine. Predictive models will be developed to identify the socio-ecological contexts in which risk from rats is highest. To simultaneously quantify the impacts of rodent control activities on wildlife population health, the research will test whether rodent control through chemical rodenticides is associated with changes in the genetic diversity of rats and higher infection risk for Escherichia coli in both rats and free-living cats. The proposed project will be the first to quantify the feedbacks between humans and rodent pests and will advance ecological and public health knowledge applicable to cities around the world. Further, the project will provide societal benefits by improving public health, social justice, and support for urban nature conservation while providing special education and training opportunities in field research for urban and minority students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.