Relationship between Physicochemical Characteristics and Pathogenic Leptospira in Urban Slum Waters

Abstract

Leptospirosis, a zoonosis caused by pathogenic Leptospira, primarily affects tropical, developing regions, especially communities without adequate sanitation. Outbreaks of leptospirosis have been linked with the presence of pathogenic Leptospira in water. In this study, we measured the physicochemical characteristics (temperature, pH, salinity, turbidity, electrical conductivity, and total dissolved solids (TDS)) of surface waters from an urban slum in Salvador, Brazil, and analyzed their associations with the presence and concentration of pathogenic Leptospira reported previously. We built logistic and linear regression models to determine the strength of association between physicochemical parameters and the presence and concentration of Leptospira. We found that salinity, TDS, pH, and type of water were strongly associated with the presence of Leptospira. In contrast, only pH was associated with the concentration of the pathogen in water. The study of physico-chemical markers can contribute to a better understanding of the occurrence of Leptospira in water and to the identification of sources of risk in urban slum environments.

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

“…This indicates that besides the adjacent sewers, there are other sources of fecal pollution and pathogenic Leptospira . Previous studies hypothesized that intense rainfall events may mobilize pathogenic Leptospira and human pollution markers occurring in soils in higher elevated areas and transport them with the storm runoff to lower areas, ,, where sewers are located. Notably, the construction of conventional sewers does not canalize stormwater, and thus, runoff may still contribute to the contamination observed in conventionally closed sewer sections.…”

Leptospirosis and the Environment: A Review and Future Directions

“…For example, Leptospira , both pathogenic and not, appear capable of surviving long periods under both low and high temperature ranges [ 8 , 69 , 70 , 71 ]. They also appear to survive in a range of pH levels, dependent on the strain and the presence of other microbiota, such as bacteria and fungi [ 8 , 69 , 70 , 71 , 72 , 73 , 74 ]. Additionally, pathogenic Leptospira seem capable of surviving in waters with low nutrients, which indicates that they are likely present in streams and waterways across a far greater range of physiographic and hydrologic conditions than previously expected [ 8 , 69 , 70 ].…”

Presence of Leptospira spp. in a Mosaic of Wetlands Used for Livestock Raising under Differing Hydroclimatic Conditions

“…Several studies postulated the persistence of Leptospira spp. in different types of aquatic systems with slightly alkaline pH, high oxygen, low concentrations of heterotrophic bacteria, and low salt concentrations ( 2 , 6 , 15 , 20 , 21 ). However, no studies on the environmental factors and determinants that affect the presence of Leptospira in wetland systems have been reported.…”