Fecal Contamination and Diarrheal Pathogens on Surfaces and in Soils among Tanzanian Households with and without Improved Sanitation

Abstract

Little is known about the extent or pattern of environmental fecal contamination among households using low-cost, on-site sanitation facilities, or what role environmental contamination plays in the transmission of diarrheal disease. A microbial survey of fecal contamination and selected diarrheal pathogens in soil (n = 200), surface (n = 120), and produce samples (n = 24) was conducted in peri-urban Bagamoyo, Tanzania, among 20 households using private pit latrines. All samples were analyzed for E. coli and enterococci. A subset was analyzed for enterovirus, rotavirus, norovirus GI, norovirus GII, diarrheagenic E. coli, and general and human-specific Bacteroidales fecal markers using molecular methods. Soil collected from the house floor had significantly higher concentrations of E. coli and enterococci than soil collected from the latrine floor. There was no significant difference in fecal indicator bacteria levels between households using pit latrines with a concrete slab (improved sanitation) versus those without a slab. These findings imply that the presence of a concrete slab does not affect the level of fecal contamination in the household environment in this setting. Human Bacteroidales, pathogenic E. coli, enterovirus, and rotavirus genes were detected in soil samples, suggesting that soil should be given more attention as a transmission pathway of diarrheal illness in low-income countries.

Geophagy is Associated with Environmental Enteropathy and Stunting in Children in Rural Bangladesh

“…This finding is consistent with those of Pickering and others who found diarrheagenic E. coli in the soil of household compounds in rural Tanzania. 42 We suspect this fecal contamination was from domestic animals that were present in household compounds and from improper disposal of feces from child defecation events. In a nested sub-study, we found that only 14% of feces from study children was disposed of in the toilet and that the majority (74%) was disposed of in a nearby field or waste ditch (Christine Marie George, personal communication).…”

“…[23][24][25][26]42 However, despite this growing evidence base, interventions to intervene upon this exposure route for pediatric populations are nonexistent. Furthermore, we found that in our study population that caregivers do little to prevent children from putting soil in their mouth.…”

Fecal Indicator Bacteria Contamination of Fomites and Household Demand for Surface Disinfection Products: A Case Study from Peru

“…[2][3][4] High concentrations of fecal indicator bacteria (FIB) and pathogens can be in food, water, soil, and on hands and surfaces. 3,5 Elevated levels of fecal contamination in the environment are attributed to inadequate sanitation, a leading cause of child morbidity and mortality from diarrheal diseases, malnutrition, and stunting. 6 In addition, fecal contamination on surfaces is linked to increased risk of diarrheal disease, as highlighted by a study at a child care center in the United States.…”

“…Surface decontamination may be important, as, for example, one study from Tanzania showed dinner plates were readily contaminated with FIB and gastrointestinal pathogen markers in peri-urban households. 3 In this study, we examined household cleaning practices and the prevalence of FIB (e.g., total coliform, enterococci, and Escherichia coli) on dinner plates as indicators of the need for improved cleaning practices (e.g., surface disinfection using bleach) in four peri-urban communities near Iquitos, Peru. We also estimated the rate of new household demand for bleach for domestic disinfection using the conceptual model of adoption stages and behavioral indicators of a new demand for sanitation developed by Jenkins and Scott (2007).…”

“…3,4,8,[16][17][18] The FIB was observed on plates even though survey respondents reportedly cleaned tableware frequently, with most (80%) reporting use of soap when cleaning. These findings suggest one or more of the following: reported cleaning methods do not reflect methods used to clean the sampled plate, cleaning methods do not effectively disinfect tableware, surfaces may be rapidly recontaminated after cleaning or disinfection, or survey responses were biased to over report bleach use.…”