TY - JOUR

T1 - Effect of Sewerage on the Contamination of Soil with Pathogenic Leptospira in Urban Slums

AU - Casanovas-Massana, Arnau

AU - Neves Souza, Fabio

AU - Curry, Melanie

AU - de Oliveira, Daiana

AU - de Oliveira, Anderson S.

AU - Eyre, Max T.

AU - Santiago, Diogo

AU - Aguiar Santos, Maísa

AU - Serra, Rafael M. R.

AU - Lopes, Evelyn

AU - Xavier, Barbara IA

AU - Diggle, Peter J.

AU - Wunder, Elsio A.

AU - Reis, Mitermayer G.

AU - Ko, Albert I.

AU - Costa, Federico

N1 - This document is the Accepted Manuscript version of a Published Work that appeared in final form in Environmental Science and Technology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.est.1c04916

PY - 2021/12/7

Y1 - 2021/12/7

N2 - Leptospirosis is an environmentally transmitted zoonotic disease caused by pathogenic Leptospira spp. that affects poor communities worldwide. In urban slums, leptospirosis is associated with deficient sanitary infrastructure. Yet, the role of sewerage in the reduction of the environmental contamination with pathogenic Leptospira has not been explored. Here, we conducted a survey of the pathogen in soils surrounding open and closed sewer sections in six urban slums in Brazil. We found that soils surrounding conventionally closed sewers (governmental interventions) were 3 times less likely to contain pathogenic Leptospira (inverse OR 3.44, 95% CI = 1.66–8.33; p < 0.001) and contained a 6 times lower load of the pathogen (0.82 log10 units difference, p < 0.01) when compared to their open counterparts. However, no differences were observed in community-closed sewers (poor-quality closings performed by the slum dwellers). Human fecal markers (BacHum) were positively associated with pathogenic Leptospira even in closed sewers, and rat presence was not predictive of the presence of the pathogen in soils, suggesting that site-specific rodent control may not be sufficient to reduce the environmental contamination with Leptospira. Overall, our results indicate that sewerage expansion to urban slums may help reduce the environmental contamination with the pathogen and therefore reduce the risk of human leptospirosis.

AB - Leptospirosis is an environmentally transmitted zoonotic disease caused by pathogenic Leptospira spp. that affects poor communities worldwide. In urban slums, leptospirosis is associated with deficient sanitary infrastructure. Yet, the role of sewerage in the reduction of the environmental contamination with pathogenic Leptospira has not been explored. Here, we conducted a survey of the pathogen in soils surrounding open and closed sewer sections in six urban slums in Brazil. We found that soils surrounding conventionally closed sewers (governmental interventions) were 3 times less likely to contain pathogenic Leptospira (inverse OR 3.44, 95% CI = 1.66–8.33; p < 0.001) and contained a 6 times lower load of the pathogen (0.82 log10 units difference, p < 0.01) when compared to their open counterparts. However, no differences were observed in community-closed sewers (poor-quality closings performed by the slum dwellers). Human fecal markers (BacHum) were positively associated with pathogenic Leptospira even in closed sewers, and rat presence was not predictive of the presence of the pathogen in soils, suggesting that site-specific rodent control may not be sufficient to reduce the environmental contamination with Leptospira. Overall, our results indicate that sewerage expansion to urban slums may help reduce the environmental contamination with the pathogen and therefore reduce the risk of human leptospirosis.

KW - Environmental Chemistry

KW - General Chemistry

U2 - 10.1021/acs.est.1c04916

DO - 10.1021/acs.est.1c04916

M3 - Journal article

VL - 55

SP - 15882

EP - 15890

JO - Environmental Science and Technology

JF - Environmental Science and Technology

SN - 0013-936X

IS - 23

ER -