Fig 1.
Map of the four study areas in the city of Salvador: a) showing the location of the communities within the city, annual income distribution in the city, b) altitude gradient within each community.
Fig 2.
Final Structural equation model linking socioeconomic, environmental, exposure and demographic factors to leptospirosis sero-positivity, while accounting for the relationships among these factors.
There are 31 measured variables (in boxes) in the model (including sero-positivity), 23 of those representing 4 latent variables (in circles). Unless otherwise specified, the questions had binary responses with reference as “no”. Sanitation and peri-domestic quality score: E1 = Access to household is paved, E2 = Household floods after rain, E3 = Sewer floods, E4 = Presence of open sewer within 10 meters of the household. Socioeconomic status score: S1 = Owns a car, S2 = Owns a computer, S3 = Owns a washing machine, S4 = Food runs out before resident can afford to restock. S5 = Household ownership (reference: owned, rented), S6 = Education level (>5 years, 5–9 years, 9–12 years, >12 years of education). S7 = Maximum income in the household (in Brazilian Reais, continuous), S8 = Household has unplastered walls. Exposure score: In the past 12 months, the resident had Ex1 = Contact with sewage water, Ex2 = Contact with floodwater, Ex3 = Cleaned a sewer, Ex4 = Contact with mud. Protective measures: In the household P1 = Prevent trash accumulation, P2 = Wear shoes, P3 = Kill rats, Outside the household P4 = Clean peri-domestic area, P5 = Wear boots or gloves, P6 = Kill rats, P7 = Restructure sewer flow. One-sided arrows represents a causal influence originating from the variable at the base of the arrow, with the width of the arrow representing the strength of the relationship. Double-sided arrows represent a correlation. The small double-sided arrows and numbers next to each variable represent the error variance.
Table 1.
Key variables measured in the four communities.
Table 2.
Summary of generalized linear mixed effects model with sero-status of residents as binary response variable.
The predictor variables were those maintained in the final structural equation model, but also controls for community and household (random effect) effects.
Fig 3.
Model predicted relationships of three generalized linear mixed effect models illustrating the relationship between inadequate sanitation, poor socioeconomic conditions, and leptospirosis risk.
The panels show predicted marginal probability of a) sero-positivity in relation to contact with sewer water, b) perceived vulnerability to leptospirosis in relation to contact with sewer water, and c) contact with sewer water as a function of socioeconomic status (score).