Collaborative mapping: Perceived environmental risk of leptospirosis in Urban communities in Salvador, Brazil

Environmental risks disproportionately affect socially vulnerable populations, yet most studies on urban leptospirosis have not captured residents' perceptions of these risks. We conducted a cross-sectional study between August 2018 and March 2019 across four communities in Salvador, Brazil (Marechal Rondon, Alto do Cabrito, Nova Constituinte, and Rio Sena) using a collaborative mapping approach to explore residents' perceptions of environmental health risks. The majority of participants identified sewage as the primary health risk (26-39% across communities), followed by garbage (22-28%), while leptospirosis itself was perceived as a high-risk problem by very few participants (0-4%). We found no spatial concordance between areas perceived as high risk for leptospirosis and households testing positive for the disease, nor between areas perceived as high rat risk and the locations of positive rat traps and track plates. However, a higher density of rubbish piles was observed in areas residents identified as high rubbish risk, suggesting that perceptions do reflect some on-the-ground realities. Collaborative mapping proved an effective method for capturing individual perceptions of environmental health risks and promoting community participation in generating locally relevant information. The disconnect between perceived and actual transmission risk may reflect that residents are more attuned to the broader social and environmental determinants of leptospirosis, such as sanitation and waste, than to the disease itself, a distinction that warrants further investigation to better integrate community knowledge into disease prevention and control strategies.