Inequality in Exposure and Knowledge Drives Vulnerability to Rat-Associated Leptospirosis

To predict and prevent public health risks from urban rats, studies often examine zoonotic pathogen prevalence in rats in different urban environments. However, human exposure to rats and their awareness of the associated risks are poorly understood. In this study, we aimed to identify factors associated with two aspects of vulnerability to leptospirosis as a model rat-associated disease: (1) exposure to rat urine in the home and (2) lack of awareness that rats carry leptospirosis. To collect data on residents' experiences and knowledge about rats, we mailed a survey to randomly selected households along an income gradient in Chicago. Of 432 complete cases, 36% had observed rat urine in the home and 73% were unaware that rats carry leptospirosis. Using logistic regression, we found that non-white respondents had over three times higher odds of observing rat urine in the home than white respondents. Dog owners and respondents who sought out information about rats, regardless of source, were more likely to be aware that rats carry leptospirosis. When we examined both aspects of vulnerability simultaneously using multinomial regression, we found that residents most vulnerable to leptospirosis (who had been exposed to urine and were not aware that rats carry leptospirosis) were significantly less likely to be white and less likely to be dog owners. Our results suggest that more public education is needed about rat-associated diseases spread through feces and urine and that exposure to rats should be considered another environmental health burden that is disproportionately persistent in underserved communities of color.